WO2015100075A1 - Solid binary copper-silicon material catalysts for emissions control - Google Patents

Solid binary copper-silicon material catalysts for emissions control Download PDF

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Publication number
WO2015100075A1
WO2015100075A1 PCT/US2014/070659 US2014070659W WO2015100075A1 WO 2015100075 A1 WO2015100075 A1 WO 2015100075A1 US 2014070659 W US2014070659 W US 2014070659W WO 2015100075 A1 WO2015100075 A1 WO 2015100075A1
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Prior art keywords
copper
surface area
porous high
gas
silicon
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PCT/US2014/070659
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French (fr)
Inventor
Vasgen A. Shamamian
Robert Thomas Larsen
Michael WEBERSKI, Jr.
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Dow Corning Corporation
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Publication of WO2015100075A1 publication Critical patent/WO2015100075A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
    • B01D53/945—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC] characterised by a specific catalyst
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/02—Boron or aluminium; Oxides or hydroxides thereof
    • B01J21/04—Alumina
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
    • B01J21/08—Silica
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/72—Copper
    • B01J35/30—
    • B01J35/612—
    • B01J35/615—
    • B01J35/633—
    • B01J35/635—
    • B01J35/647—
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/03—Precipitation; Co-precipitation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/207—Transition metals
    • B01D2255/20761—Copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/30—Silica
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/01—Engine exhaust gases
    • B01D2258/014—Stoichiometric gasoline engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2510/00—Surface coverings
    • F01N2510/06—Surface coverings for exhaust purification, e.g. catalytic reaction
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • Combustion engines may emit pollutants including CO, NO x , and hydrocarbons.
  • pollutants including CO, NO x , and hydrocarbons.
  • the present patent application relates to catalytically converting pollutants of an exhaust gas using solid binary copper-silicon materials.
  • the solid binary copper-silicon materials may facilitate catalytically converting one or more of CO, NO x , plain hydrocarbons, and oxygenated hydrocarbons, as defined below.
  • Such solid binary copper- silicon materials may thus find use in an emissions control device, such as a mobile emissions control device or a stationary emissions control device, as defined below.
  • a method may include combusting a substance (10), thereby producing an exhaust gas having a pollutant therein (e.g., at least one of CO, NO x and hydrocarbons (e.g. plain hydrocarbons and/or oxygenated hydrocarbons, as defined below)).
  • the method may further comprise contacting the exhaust gas with a solid binary copper-silicon material (20) and, concomitantly, catalytically converting (30) at least a portion of the pollutant into a product via the solid binary copper-silicon material.
  • catalytically convert and the like means to chemically react at least some amount of a pollutant via a catalyst.
  • catalyst and the like means a material that lowers the activation energy of a chemical reaction without being consumed by the reaction.
  • the solid binary copper-silicon catalyst materials described herein are not consumed during their participation in converting the pollutants.
  • the solid binary copper-silicon materials are a heterogeneous catalyst.
  • heterogeneous catalyst means a catalyst that is a different phase of matter than the pollutant.
  • the temperature of the solid binary copper-silicon material catalysts may play a role in the relative efficiency of the solid binary copper-silicon material catalysts. For example, low temperatures may result in lower conversion rates of a pollutant to a non- pollutant.
  • the solid binary copper-silicon materials may realize a light- off temperature for a given pollutant.
  • "light-off temperature” and the like means the temperature of a solid binary copper-silicon material catalyst at which at least 50 molar % of a particular pollutant is catalytically converted to a non-pollutant.
  • a solid binary copper-silicon material catalyst may realize different light-off temperatures for different pollutants.
  • the solid binary copper-silicon materials may realize low light-off temperatures (e.g., below a normal operating exhaust gas temperature of an automobile, such as 400 °C to 600°C).
  • the solid binary copper-silicon materials may realize a light-off temperature for CO of about 170°C when the residence time of the pollutant is about 300 ms (milliseconds) and the specific surface area of the solid binary copper-silicon materials is about 0.11 m /g and the mass of the solid binary copper-silicon materials is about 0.89 g.
  • the solid binary copper-silicon materials may realize a light-off temperature for NO of about 140°C and at the above conditions (e.g., the residence time, specific surface area and mass of solid binary copper-silicon materials noted above).
  • the solid binary copper-silicon materials may realize a light-off temperature for propane of about 300°C and at the above conditions.
  • solid binary copper-silicon materials located on a high-surface area support may realize a light-off temperature for NO as low as ambient temperature (e.g., about 25°C) and at the above conditions (e.g., the residence time and mass of solid binary copper-silicon materials noted above).
  • the solid binary copper-silicon materials may catalytically convert at least some of at least one pollutant at temperatures other than the light-off temperature(s) (e.g. at temperatures lower than a light-off temperature).
  • a pollutant is CO
  • the solid binary copper-silicon materials may convert at least 1 molar % of the CO to C0 2 at a temperature of from about 50°C to about 200°C when the residence time of the pollutant is about 300 ms (milliseconds) and the specific surface area of the solid binary copper-silicon materials is about 0.11 m /g and the mass of the solid binary copper- silicon materials is about 0.89 g.
  • the solid binary copper-silicon materials may convert at least 10 molar % of the CO to C0 2 at a temperature of not greater than 190°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the CO to C0 2 at a temperature of not greater than 180°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the CO to C0 2 at a temperature of not greater than 170°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the CO to C0 2 at a temperature of not greater than 160°C and at the above conditions.
  • the solid binary copper-silicon materials may convert at least 10 molar % of the CO to C0 2 at a temperature of not greater than 150°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the CO to C0 2 at a temperature of not greater than 140°C and at the above conditions. In some embodiments, the solid binary copper- silicon materials may convert at least 20 molar % of the CO to C0 2 . In some embodiments, the solid binary copper-silicon materials may convert at least 30 molar % of the CO to C0 2 . In some embodiments, the solid binary copper-silicon materials may convert at least 40 molar % of the CO to C0 2 .
  • the solid binary copper-silicon materials may convert at least 50 molar % of the CO to C0 2 . In some embodiments, the solid binary copper-silicon materials may convert at least 75 molar % of the CO to C0 2 . In some embodiments, the solid binary copper-silicon materials may convert at least 85 molar % of the CO to C0 2 . In some embodiments, the solid binary copper-silicon materials may convert at least 95 molar % of the CO to C0 2 . In some embodiments, the solid binary copper- silicon materials may convert at least 98 molar % of the CO to C0 2 .
  • the solid binary copper-silicon materials may convert at least 1 molar % of the NO x to N 2 at a temperature of from about 50°C to about 200°C when the residence time of the pollutant is about 300 ms and the specific surface area of the solid binary copper-silicon materials is about 0.11 m /g and the mass of the solid binary copper-silicon materials is about 0.89 g.
  • the solid binary copper-silicon materials may convert at least 10 molar % of the NO x to N 2 at a temperature of not greater than 180°C and at the above conditions.
  • the solid binary copper-silicon materials may convert at least 10 molar % of the NO x to N 2 at a temperature of not greater than 160°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the NO x to N 2 at a temperature of not greater than 140°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the NO x to N 2 at a temperature of not greater than 120°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the NO x to N 2 at a temperature of not greater than 110°C and at the above conditions.
  • the solid binary copper-silicon materials may convert at least 10 molar % of the NO x to N 2 at a temperature of not greater than 100°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the NO x to N 2 at a temperature of not greater than 90°C and at the above conditions. In some embodiments, the solid binary copper-silicon materials may convert at least 20 molar % of the NO x to N 2 . In some embodiments, the solid binary copper-silicon materials may convert at least 30 molar % of the NO x to N 2 .
  • the solid binary copper-silicon materials may convert at least 40 molar % of the NO x to N 2 . In some embodiments, the solid binary copper- silicon materials may convert at least 50 molar % of the NO x to N 2 . In some embodiments, the solid binary copper-silicon materials may convert at least 75 molar % of the NO x to N 2 . In some embodiments, the solid binary copper-silicon materials may convert at least 85 molar % of the NO x to N 2 .
  • the solid-binary copper-silicon materials are utilized with a high-surface area support, as described below, the solid-binary copper-silicon materials are utilized with a high- surface area support may realize any of the above described NOx molar conversion amounts at from 50° to 200°C and at the above conditions (i.e., when the residence time of the pollutant is about 300 ms and the mass of the solid binary copper- silicon materials is about 0.89 g).
  • the conversion of NO x to N2 may be completed at lower temperatures and/or with higher conversion rates.
  • solid binary copper-silicon materials located on a high-surface area support may convert at least 10 molar % of the NO x to N 2 at a temperature of not greater than 80°C at the above conditions. In one embodiment, solid binary copper-silicon materials located on a high-surface area support may convert at least 10 molar % of the NO x to N 2 at a temperature of not greater than 70°C at the above conditions. In one embodiment, solid binary copper-silicon materials located on a high-surface area support may convert at least 10 molar % of the NO x to N 2 at a temperature of not greater than 60°C at the above conditions.
  • solid binary copper- silicon materials located on a high-surface area support may convert at least 10 molar % of the NO x to N 2 at a temperature of not greater than 50°C at the above conditions. In one embodiment, solid binary copper-silicon materials located on a high-surface area support may convert at least 10 molar % of the NO x to N 2 at a temperature of not greater than 40°C at the above conditions. In one embodiment, solid binary copper-silicon materials located on a high-surface area support may convert at least 10 molar % of the NO x to N 2 at a temperature of not greater than 30°C at the above conditions.
  • solid binary copper- silicon materials located on a high-surface area support may convert at least 10 molar % of the NO x to N 2 at at about ambient temperature at the above conditions. In some embodiments, solid binary copper-silicon materials located on a high-surface area support may convert at least 20 molar % of the NO x to N 2 . In some embodiments, solid binary copper-silicon materials located on a high- surface area support may convert at least 30 molar % of the NO x to N 2 . In some embodiments, solid binary copper- silicon materials located on a high-surface area support may convert at least 40 molar % of the NO x to N 2 .
  • solid binary copper-silicon materials located on a high-surface area support may convert at least 50 molar % of the NO x to N 2 . In some embodiments, solid binary copper-silicon materials located on a high-surface area support may convert at least 60 molar % of the NO x to N 2 . In some embodiments, solid binary copper- silicon materials located on a high-surface area support may convert at least 70 molar % of the NO x to N 2 . In some embodiments, solid binary copper-silicon materials located on a high-surface area support may convert at least 80 molar % of the NO x to N 2 .
  • solid binary copper-silicon materials located on a high-surface area support may convert at least 90 molar % of the NO x to N 2 .
  • solid binary copper- silicon materials located on a high-surface area support may convert at least 95 molar % of the NO x to N 2 .
  • solid binary copper-silicon materials located on a high-surface area support may convert at least 99 molar % of the NO x to N 2 .
  • solid binary copper-silicon materials located on a high-surface area support may convert at least 99.99 molar % of the NO x to N 2 .
  • the solid binary copper-silicon materials may convert at least 1 molar % of the plain hydrocarbon to water and/or C0 2 at a temperature of from about 200°C to about 350°C when the residence time of the pollutant is about 300 ms and the specific surface area of the solid binary copper- silicon materials is about 0.11 m /g and the mass of the solid binary copper-silicon materials is about 1.11 g.
  • the solid binary copper-silicon materials may convert at least 10 molar % of the plain hydrocarbon to water and/or C0 2 at a temperature of not greater than 325°C and at the above conditions.
  • the solid binary copper-silicon materials may convert at least 10 molar % of the plain hydrocarbon to water and/or C0 2 at a temperature of not greater than 300°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the plain hydrocarbon to water and/or C0 2 at a temperature of not greater than 275°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the plain hydrocarbon to water and/or C0 2 at a temperature of not greater than 250°C and at the above conditions.
  • the solid binary copper-silicon materials may convert at least 20 molar % of the plain hydrocarbon to water and/or C0 2 . In some embodiments, the solid binary copper-silicon materials may convert at least 30 molar % of the plain hydrocarbon to water and/or C0 2 . In some embodiments, the solid binary copper-silicon materials may convert at least 40 molar % of the plain hydrocarbon to water and/or C0 2 . In some embodiments, the solid binary copper-silicon materials may convert at least 50 molar % of the plain hydrocarbon to water and/or C0 2 . In some embodiments, the solid binary copper-silicon materials may convert at least 75 molar % of the plain hydrocarbon to water and/or C0 2 .
  • the solid binary copper-silicon materials may convert at least 95 molar % of the plain hydrocarbon to water and/or C0 2 .
  • the solid-binary copper-silicon materials are utilized with a high-surface area support, as described below, the solid-binary copper-silicon materials are utilized with a high-surface area support may realize any of the above described plain hydrocarbon molar conversion amounts at from 200° to 350°C and at the above conditions.
  • the solid binary copper-silicon materials may also catalytically convert pollutants of an exhaust gas at higher temperatures.
  • the exhaust gas is from an internal combustion engine.
  • the internal combustion engine is a gasoline-fueled internal combustion engine.
  • the solid binary copper-silicon materials catalytically convert pollutants at normal operating exhaust gas temperatures of the gasoline-fueled internal combustion engine, such as from about 400°C to about 600°C.
  • the internal combustion engine is a diesel-fueled internal combustion engine.
  • the solid binary copper-silicon materials may catalytically convert pollutants at normal operating exhaust gas temperatures of the diesel-fueled internal combustion engine, such as from about 200°C to about 400°C.
  • the solid binary copper-silicon materials may catalytically convert pollutants of an exhaust gas at high operating temperatures of an engine.
  • the solid binary copper-silicon materials may catalytically convert pollutants of an exhaust gas at a temperature from about 50°C to about 1100°C.
  • the solid binary copper-silicon materials may catalytically convert pollutants of an exhaust gas at a temperature from about 80°C to about 900°C.
  • the solid binary copper-silicon materials may catalytically convert pollutants of an exhaust gas at a temperature from about 100°C to about 600°C.
  • the solid binary copper-silicon materials may catalytically convert pollutants of an exhaust gas at a temperature from about 300°C to about 600°C. In other embodiments, the solid binary copper-silicon materials may catalytically convert pollutants of an exhaust gas at a temperature from about 600°C to about 1100°C.
  • the pollutants may be catalytically converted via the solid binary copper- silicon materials.
  • the catalytically converting may include catalytically oxidizing the CO into C0 2 (e.g., CO + 0 2 C0 2 ).
  • the catalytically converting may include catalytically reducing the NO x into N 2 (e.g., NO + CO -» N 2 + C0 2 and/or 2NO -» N 2 + 0 2 ).
  • the catalytically converting may include catalytically oxidizing the plain hydrocarbons into at least one of C0 2 and H 2 0 (e.g., C 3 H 8 + 5 0 2 3 C0 2 + 4 H 2 0).
  • the catalytically converting may include catalytically oxidizing the oxygenated hydrocarbons into at least one of C0 2 and H 2 0 (e.g., C 2 H 6 0 + 3 0 2 -> 2 C0 2 + 3 H 2 0).
  • the method may include combusting (10) the substance, thereby producing the exhaust gas.
  • the method may further comprise flowing (14) the exhaust gas from the internal combustion engine to an emission control device that includes the solid binary copper- silicon material (with or without a high- surface area support).
  • combustion and the like means burning a substance in the presence of oxygen.
  • exhaust gas and the like means a gas that is produced as a result of burning a substance in the presence of oxygen, i.e., combusting.
  • An exhaust gas may include gaseous forms of at least one pollutant, such as, for example, CO, NO x , plain hydrocarbons, and/or oxygenated hydrocarbons.
  • An exhaust gas may also include gaseous forms of H 2 , H 2 0, C0 2 , and 0 2 , among others.
  • An exhaust gas may also include some amount of entrained particulate matter (e.g., soot) and/or some amount of entrained liquid (e.g., water droplets), among others.
  • Sources of exhaust gas(es) include internal combustion engines (e.g., gasoline and/or diesel engines), external combustion engines (e.g., coal or gas fired power plants; steam engines), and/or chemical processing facilities (e.g., oil refineries).
  • solid binary copper-silicon material and the like means a solid (i.e, not a liquid or a gas) material that includes at least one of (a) a binary copper silicide and (b) a copper-silicon solid solution.
  • binary copper silicide and the like means an intermetallic compound of the formula Cu x Si y , where X is a positive real number, where Y is a positive real number, and where the ratio of X to Y is such that a silicide may be formed. Typically, the ratio of "X" to "Y” is from about 3: 1 to about 9: 1.
  • copper-silicon solid solution and the like means a solid solution comprised of (and sometimes consisting essentially of) copper and at least some silicon, where the solid solution comprises not greater than 12 at% silicon.
  • the solid binary copper silicide material includes at least some Cu 5 Si (also known as "Cuo. 83 Sio.17”).
  • the solid binary copper silicide material includes at least some Cu 3 Si.
  • the solid binary copper silicide material includes at least some and Cui 5 Si 4 (also known as "Cu 3 . 72 Si”).
  • the solid binary copper silicide material includes at least some Cu 4 Si.
  • the solid binary copper silicide material includes at least some Cu 7 Si.
  • the solid binary copper silicide material includes at least some CU0. S10.1. In some embodiments, the solid binary copper silicide material includes a combination of two or more of Cu 5 Si, Cu 3 Si, CU15S14, Cu 4 Si, Cu 7 Si, CU0.9S10.1 and a copper-silicon solid solution.
  • the solid binary copper-silicon material may be in particulate form and can be used as is.
  • the size distribution of the particulate, and hence the specific surface area i.e., surface area per unit mass of solid binary copper-silicon material
  • the solid binary copper-silicon material may be deposited on the surface of a monolith and/or a honeycomb material (see, for instance, U.S. Patent No. 4,987,112).
  • particulate binary copper-silicon material may be introduced into an aqueous coating solution, thereby creating a slurry.
  • the monolith and/or honeycomb material may be coated with the slurry, thereby depositing the solid binary copper-silicon material on the surface of the monolith and/or honeycomb material, thereby creating a high- surface area material loaded with binary copper-silicon material.
  • Other methods of producing high-surface area support materials loaded with binary copper-silicon material are described below.
  • the catalytically converting comprises catalytically converting pollutants of an exhaust gas.
  • pollutants include CO (i.e. carbon monoxide), NO x , plain hydrocarbons, oxygenated hydrocarbons, and combinations thereof.
  • the exhaust gas includes from 0.01 to 20 vol. % of the CO.
  • the exhaust gas includes not greater than 10 vol. % of the CO.
  • the exhaust gas includes not greater than 5 vol. % of the CO.
  • the exhaust gas includes not greater than 1 vol. % of the CO.
  • the exhaust gas includes at least 0.05 vol. % of the CO.
  • the exhaust gas includes at least 0.1 vol. % of the CO.
  • the pollutant may include NO x .
  • NO x means NO, N0 2 , N 2 0, N 2 0 4 , N 2 0 5 , and combinations thereof.
  • the exhaust gas includes from 1 to 100,000 ppmv (parts per million by volume) of the NO x .
  • the exhaust gas includes not greater than 50,000 ppmv of the NO x .
  • the exhaust gas includes not greater than 25,000 ppmv of the NO x .
  • the exhaust gas includes not greater than 10,000 ppmv of the NO x .
  • the exhaust gas includes not greater than 5,000 ppmv of the NO x .
  • the exhaust gas includes not greater than 2,000 ppmv of the NO x . In yet another embodiment, the exhaust gas includes at least 5 ppmv of the NO x . In another embodiment, the exhaust gas includes at least 10 ppmv of the NO x . In yet another embodiment, the exhaust gas includes at least 50 ppmv of the NO x . In another embodiment, the exhaust gas includes at least 100 ppmv of the NO x .
  • the pollutant may include plain hydrocarbons and/or oxygenated hydrocarbons.
  • plain hydrocarbon and/or the like means a compound consisting only of carbon and hydrogen.
  • the plain hydrocarbons may comprise propane and/or larger plain hydrocarbons such as butane, octane and the like.
  • the plain hydrocarbons comprise ethane and/or methane.
  • oxygenated hydrocarbon and the like means a compound comprising carbon, hydrogen, and at least one oxygen atom.
  • the exhaust gas includes at least 1 ppmv of at least one of the plain hydrocarbons and the oxygenated hydrocarbons.
  • the exhaust gas includes at least 10 ppmv of at least one of the plain hydrocarbons and the oxygenated hydrocarbons. In yet another embodiment, the exhaust gas includes at least 50 ppmv of at least one of the plain hydrocarbons and the oxygenated hydrocarbons. In another embodiment, the exhaust gas includes at least 100 ppmv of at least one of the plain hydrocarbons and the oxygenated hydrocarbons.
  • an emission control device uses the solid binary copper- silicon material (with or without a high-surface area support) to catalytically convert an exhaust gas.
  • a combustion apparatus e.g., an exhaust gas source such as a mobile exhaust gas source or a stationary exhaust gas source
  • the exhaust gas (150) then flows to an emission control device (200).
  • the emission control device (200) comprises a housing.
  • the housing has a waste gas inlet (210) for receiving the exhaust gas (150).
  • the exhaust gas (150) includes a pollutant when it enters the waste gas inlet (210).
  • the pollutant comprises a first amount of at least one of CO, NO x , plain hydrocarbons and oxygenated hydrocarbons.
  • the housing includes a solid binary copper-silicon material (250) (with or without a high-surface area support) disposed therein and configured to communicate with the exhaust gas (150).
  • the housing also has a treated gas outlet (230) for discharging the exhaust gas as a treated exhaust gas (170). Due to the solid binary copper-silicon material (250), the treated exhaust gas (170) may include a second (e.g., decreased) amount of at least one of the CO, the NO x , the plain hydrocarbons and the oxygenated hydrocarbons.
  • emission(s) control device and the like means a device having at least some solid binary copper-silicon material therein and configured to receive an exhaust gas having a pollutant.
  • An emissions control device may be a stationary emissions control device or a mobile emissions control device.
  • a stationary emissions control device is an emissions control device that receives an exhaust gas from a stationary source. Examples of stationary emissions control devices include emissions control devices that receive exhaust gas(es) from such stationary sources as coal-fired power plants, natural gas fired power plants, oil refineries, incinerators, wood stoves, and generators, among others.
  • a mobile emissions control device is an emissions control device that receives an exhaust gas from a mobile source. Examples of mobile emissions control devices include emissions control devices that receive exhaust gas(es) from such mobile sources as gasoline powered automobiles, diesel powered automobiles, ships, airplanes, and lawnmowers, among others.
  • an emissions control device of an automobile may be configured to realize a normal operating residence time of from about 25 ms to about 500 ms. In one embodiment, an emissions control device of an automobile may be configured to realize a residence time of from about 50 ms to about 300 ms.
  • "residence time” and the like means the time for an appropriate volume of an exhaust gas to flow through an amount of solid binary copper-silicon material. For example, for an exhaust gas stream flowing through a cylindrical tube packed with an amount of solid binary copper-silicon particles, the residence time equals the bulk volume of the amount of solid binary copper- silicon particles divided by the flow rate of the exhaust gas stream.
  • bulk volume of an amount of particles equals the volume of the particles plus the volume of the interparticle void spaces (i.e., spaces between the particles) plus the volume of the pores of the particles (if any).
  • the present patent application also relates to methods of producing binary copper- silicon materials located on a high-surface area support material.
  • FIG. 3 one embodiment of a method for producing solid binary copper-silicon materials located on a high-surface area porous support material is illustrated.
  • the method comprises (a) forming copper metal particles on surfaces of a porous support material (100), and (b) converting the copper metal particles to solid binary copper-silicon materials (200).
  • the converting step may include recovering (FIG. 7) a final product having the solid binary copper-silicon material located within the pores of the porous high-surface area material.
  • the final product may be utilized in catalytic applications, such as in any of the catalytic applications described above.
  • copper metal particles means particles consisting essentially of elemental copper (Cu). Copper metals particles are generally substantially free of oxygen and other materials that would prevent the copper reacting with silicon to form copper silicide.
  • the copper metal particles generally have a bulk particle size (Do.os to D0.95) of from 3 nanometer (nm) to 100 microns ( ⁇ ).
  • the copper metal particles have a mean particle size (D0.5) of from 4 nanometers to 1 micron.
  • the copper metal particles have a mean particle size of from 5 nanometers to 500 nanometers.
  • the copper metal particles have a mean particle size of from 5 nanometers to 100 nanometers.
  • the copper metal particles have a mean particle size of from 5 nanometers to 50 nanometers.
  • porous high-surface area material means a material having a plurality of pores, and an initial BET surface area of from 0.1 m 2 /gram to 2000 m 2 /gram.
  • initial BET surface area means a BET surface area of the material prior to forming the copper metal particles on surfaces of the porous high-surface area material.
  • porous high-surface area materials examples include aluminas (e.g., ⁇ - ⁇ 1 2 0 3 ), silicas, aluminosilicates, silicon carbides, silicon nitrides, activated carbon, zeolites, titania, zirconia, ceria, and mixtures thereof, and all of which may be doped or undoped.
  • the porous high-surface area material is an alumina.
  • the porous high-surface area material is a silica.
  • the porous high- surface area material is an aluminosilicate.
  • the porous high-surface area material is a silicon carbide.
  • the porous high-surface area material is a silicon nitride. In another embodiment, the porous high-surface area material is an activated carbon. In yet another embodiment, the porous high-surface area material is a zeolite. In another embodiment, the porous high-surface area material is a titania. In yet another embodiment, the porous high-surface area material is a zirconia. In another embodiment, the porous high-surface area material is a ceria. Known BET Surface Areas for these materials are provided below.
  • the porous high-surface area material BET has an initial surface area of at least 1 m /gram. In another embodiment, the porous high-surface area material BET has an initial surface area of at least 5 m /gram. In yet another embodiment, the porous high-surface area material BET has an initial surface area of at least 10 m /gram. In another embodiment, the porous high-surface area material BET has an initial surface area of at least 20 m /gram.
  • "initial pore volume” means a pore volume of the material prior to forming the copper metal particles on surfaces of the porous high-surface area material.
  • the porous high-surface area material realizes an initial pore volume of at least 0.1 cm /gram. In another embodiment, the porous high-surface area material realizes an initial pore volume of at least 0.25 cm /gram.
  • the porous high-surface area material realizes an initial pore volume of at least 0.5 cm /gram. In another embodiment, the porous high- surface area material realizes an initial pore volume of at least 0.75 cm /gram. In yet another embodiment, the porous high-surface area material realizes an initial pore volume of at least
  • the porous high-surface area material may be in any suitable form, including powders, granules, beads (e.g., spheres), structured materials (e.g. monoliths, honeycomb, rods, needles, cylinders, etc.).
  • high temperature applications e.g., where the final product is exposed to temperatures above about 300°C
  • high silicon aluminosilicates e.g. 60-40 AI 2 O 3 -S1O 2
  • silica silicon carbide
  • silicon nitride porous high-surface area materials may be preferred.
  • the copper metal particles are located on the high-surface area support material.
  • the copper metal particles may be located on outer surfaces of the high-surface area support material and/or within pores of the high-surface area support material.
  • the copper metal particles may be partially located within the pores (e.g., a particle may partially located within a pore and partially located on an outer surface; a particle may be partially located within a pore and partially embedded within the high-surface area support material, among other scenarios) or fully located within the pores (e.g., fully within a pore without being embedded in the high- surface area support material).
  • the same principles apply to copper oxide particles, described below, and to the binary copper-silicon materials produced from the copper metal particles or produced from the copper oxide particles.
  • the copper metal particles may be formed (100) via any suitable method.
  • the forming step (100) may include precipitating the copper metal particles in a bath (400).
  • the precipitating step (400) comprises co-precipitating the copper metal particles and the porous high-surface area material in a bath.
  • both the copper metal particles and the porous high-surface area support are precipitated (produced) in the same bath.
  • copper nanoparticles can be prepared directly by addition of 1 mL of 0.01 M copper (II) acetate in ethanol to 5 mL water (all materials degassed of oxygen and held under inert nitrogen conditions).
  • PVP polyvinylpyrrolidone
  • TEOS Tetraethylorthosilicate
  • the sol may be aged at 50 - 100°C.
  • the pH of the solution can be adjusted as appropriate to further facilitate interaction of the sol gel with the copper nanoparticles.
  • the slurry mixture can then be filtered and dried (e.g., at 100 - 150°C) while maintaining an inert atmosphere.
  • the powder can then be heated (e.g., to 450-500°C) under reducing (e.g., H 2 ) or inert (e.g., N 2 /Ar) conditions to drive off additional moisture and remove any capping agent, after which the reducing step (460), described below, may be accomplished.
  • reducing e.g., H 2
  • inert e.g., N 2 /Ar
  • the precipitating step (400) comprises precipitating the copper metal particles in a bath comprising the porous high-surface area material.
  • the porous high-surface area material may be pre-existing in the bath, and the copper metal particles may be precipitated, such as via a change in pH of the bath.
  • the precipitated copper metal particles are located on surfaces of the porous high-surface area material.
  • a method may include maintaining the precipitated copper metal particles in a non-oxidizing environment (420) until the conversion step (200).
  • the copper metal particles may be maintained in a liquid or gaseous environment that prevents / restricts oxidation of the copper metal of the copper metal particles at least until initiation of the converting step (200).
  • Exposing the copper metal particles to an oxidizing environment may result in the formation of a native oxide layer on the surface of the copper metal particles.
  • the presence of oxygen, such as with a native oxide layer may, inhibit / prevent proper conversion of the copper metal particles to binary copper-silicon materials.
  • a method may include exposing the metal particles to an oxidizing environment (440). For instance, it may be difficult or impractical to maintain the copper metal particles in a non-oxidizing environment after precipitation. As one example, it may be efficient to dry the copper metal particles and corresponding porous high-surface area material in air for transportation or other purposes.
  • a method may comprise exposing the copper metal particles to a reducing environment (460) so as to, for example, remove any oxides from the copper metal particles (e.g., native oxide layers on surface of the copper metal particles).
  • the exposing the copper metal particles to a reducing environment step (460) may include, for example, exposing the copper metal particles and corresponding porous high-surface area material to a reducing agent.
  • a "reducing agent” means any material that reduces a copper precursor or a copper oxide to copper metal at elevated temperatures.
  • the reducing agent comprises one of ammonia and a hydrogen-containing gas (e.g., H 2 gas).
  • the reducing agent consists essentially of hydrogen gas.
  • the exposing step (460) may include maintaining an oxygen-free atmosphere.
  • an "oxygen-free atmosphere means a gaseous environment that contains less than 1000 ppm, or less than 100 ppm, or less than 10 ppm oxygen (0 2 ).
  • copper oxide particles may also or alternatively be precipitated via the precipitating step (400).
  • the copper oxide particles may be subsequently reduced as per step (460), described above, and/or as per the reducing step (560) described relative to FIG. 5, below.
  • the following preparation method for copper nanoparticles on a porous silica support can be used. Add a 4 M NaOH solution dropwise at a constant rate to a vigorously stirred 0.5 M Cu(N0 3 ) 2 solution to produce copper oxide nanoparticles. Tetraethylorthosilicate (TEOS) can then be added in the proper proportion to achieve the desired wt. % of Cu vs.
  • TEOS Tetraethylorthosilicate
  • the pH of the slurry mixture can be varied as appropriate to facilitate interaction of the copper oxide nanoparticles with the silica sol.
  • the slurry mixture can then be filtered and rinsed with DI water, dried at 100 - 150°C, calcined in air for 3-5 hours at 450°C, reduced in 1% hydrogen in argon at 500°C (1 hr), and finally reduced in 100% hydrogen at 500°C (1 hr).
  • the forming step (100) may also or alternatively include infiltrating pores of the porous high- surface area material with a copper precursor (500).
  • a "copper precursor” is a copper salt (e.g., copper nitrate) or copper organo- metallic compound (e.g., Cu(acac), i.e., copper acetyl acetonate) that is capable of forming copper metal particles upon appropriate subsequent reduction and/or oxidation of the copper precursor.
  • a copper precursor is dissolved in a copper precursor solution.
  • a "copper precursor solution” is a solution, aqueous or organic, comprising a copper precursor.
  • the infiltrating step (500) may include one or more of wet impregnation (502), spray drying (504), and incipient wetness impregnation (506), as illustrated in FIG. 6.
  • the method may include the steps of reducing the copper precursor to copper metal particles (520).
  • the copper precursor and corresponding porous high-surface area material may be dried (510), such as in an oxygen- free atmosphere.
  • the copper precursor may then be reduced (520) via a reducing agent to form copper metal particles.
  • the reducing agent is a hydrogen-containing gas.
  • the copper metal particles may be maintained in a reducing environment (530), after which the converting step (200) is completed.
  • the copper metal particles may be exposed to an oxidizing environment (560) (e.g., exposed to air for transportation purposes).
  • the copper metal particles may be exposed to a reducing environment (570), so as to, for example, remove any oxides from the copper metal particles (e.g., native oxide layers on surface of the copper metal particles).
  • the exposing step (570) may include maintaining an oxygen-free atmosphere.
  • the exposing the copper metal particles to a reducing environment step (570) may include, for example, exposing the copper metal particles and corresponding porous high-surface area material to a reducing agent.
  • the reducing agent comprises one of ammonia and a hydrogen- containing gas (e.g., H 2 gas).
  • the reducing agent is a hydrogen- containing gas consisting of hydrogen gas (H 2 ) and an inert gas.
  • an "inert gas” is one or more of a noble gas and nitrogen.
  • the reducing agent consists essentially of hydrogen gas (H 2 ).
  • the reducing step (570) includes first exposing the copper particles and corresponding porous high-surface area material to a first reducing gas having a first concentration of a reducing agent, and then second exposing the copper particles and the corresponding porous high-surface area material to a second reducing gas having a second concentration of a reducing agent, wherein the second concentration is larger than the first concentration.
  • the first concentration of the first reducing gas is at least two times less than the second concentration.
  • the first concentration is at least five times less than the second concentration.
  • the first concentration is 0.1 to 2% H 2 by volume
  • the second concentration is larger than the first concentration, but not greater than 10% H 2 by volume.
  • the reducing step may (570) include third exposing the copper particles and the corresponding porous high-surface area material to a third reducing gas having a third concentration of a reducing agent, wherein the third concentration is larger than the second concentration.
  • the third concentration is at least five times larger than the second concentration.
  • the third concentration is at least ten times larger than the second concentration.
  • the third concentration is at least twenty times larger than the second concentration.
  • the third reducing gas is consists essentially of the reducing agent (e.g., consists essentially of hydrogen gas (3 ⁇ 4)).
  • the method may include oxidizing the copper precursor to copper oxide particles (540).
  • the copper precursor and corresponding porous high-surface area material may be dried (510), such as in air.
  • the copper precursor may then be oxidized (540) to form copper oxide particles.
  • the oxidizing step (540) comprises heating the copper precursor and the corresponding porous high-surface area material to a temperature sufficient to facilitate the oxidation of the copper precursor to copper oxide particles.
  • the copper precursor and the porous high-surface area material is heated to a temperature of at least 300°C but below a temperature where appreciable sintering of the copper oxide particles occurs.
  • the copper precursor and the porous high-surface area material is heated to a temperature of at least 350°C. In one embodiment, the copper precursor and the porous high-surface area material is heated to a temperature of at least 400°C. In one embodiment, the copper precursor and the porous high-surface area material is heated to a temperature of at least 450°C. In one embodiment, the copper precursor and the porous high-surface area material is heated to a temperature of at least 500°C. In any of these embodiments, the copper precursor and the porous high-surface area material may heated to a temperature of not greater than 800°C. In any of these embodiments, the copper precursor and the porous high-surface area material may heated to a temperature of not greater than 750°C.
  • the copper precursor and the porous high-surface area material may heated to a temperature of not greater than 700°C. In any of these embodiments, the copper precursor and the porous high-surface area material may heated to a temperature of not greater than 650°C. In any of these embodiments, the copper precursor and the porous high-surface area material may heated to a temperature of not greater than 600°C. In any of these embodiments, the copper precursor and the porous high-surface area material may heated to a temperature of not greater than 550°C.
  • the method may include exposing the copper oxide particles to a reducing environment (570), as described above.
  • the reducing step (570) may include exposing the copper oxide particles to a single reducing agent or multiple reducing agents, and optionally with varying concentrations, as described above.
  • the converting step (200) may include the steps of regulating the temperature to an appropriate silanation temperature (210), contacting the copper metal particles with silane materials (220), reacting the copper metal particles with the silane materials (230), and recovering a final product having binary copper- silicon materials within pores of the porous high-surface area material (240).
  • the method may include maintaining (225) the appropriate silanation temperature during the contacting step (220) and the reacting step (230).
  • the regulating step (210) is optional and may be completed when the copper particles and corresponding porous high-surface area material are outside of the appropriate silanation temperature, described below.
  • the regulating step (210) may be completed in any appropriate fashion, such as via contacting the copper particles with a fluid of appropriate temperature.
  • the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 100°C to 350°C.
  • the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 125°C to 350°C.
  • the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 150°C to 350°C.
  • the regulating step comprises bringing the copper particles and corresponding porous high- surface area material to a temperature of from 150°C to 325°C. In yet another embodiment, the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 150°C to 300°C. In another embodiment, the regulating step comprises bringing the copper particles and corresponding porous high- surface area material to a temperature of from 150°C to 275°C. In yet another embodiment, the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 150°C to 250°C.
  • the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 175°C to 250°C. In yet another embodiment, the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 175°C to 225°C. In one embodiment, the regulating step (210) comprises flowing a hydrogen- containing gas through a chamber comprising the copper particles and corresponding porous high-surface area material, wherein the hydrogen-containing gas has a temperature of from 100°C to 350°C, such as any of the above-described regulating temperature ranges. In one embodiment, the hydrogen-containing gas consists of hydrogen gas (H 2 ).
  • the contacting step (220) is generally completed, and comprises contacting the copper particles and corresponding porous high- surface area material with a silane material.
  • a "silane material” is a material having silicon and hydrogen, optionally with carbon, where the silicon of the silane material may react with the copper metal particles to form binary copper-silicon materials.
  • silane materials examples include monosilane (SiH 4 ), disilane (Si 2 3 ⁇ 4), tetramethyl-silane ((CH3) 4 Si), hexamethyldisilane ((CH 3 ) 6 Si 2 ), and chlorosilanes (e.g., H x SiCl (4 _ x), where x is from 0-3; methylchlorosilanes), among others.
  • the silane material is in the form of a silane-containing gas.
  • the silane-containing gas comprises monosilane gas (SiH 4 ).
  • the silane-containing gas comprises a mixture of monosilane gas and hydrogen (H 2 ) gas.
  • the silane-containing gas consists essentially of a mixture of monosilane gas and hydrogen gas.
  • the silane-containing gas is a dilute silane-containing gas, and contains a dilute amount of silane materials.
  • a dilute silane-containing gas is a gas having a sufficient amount of silane material to facilitate reaction of the silicon with the copper metal particles, but also having not so much silane material such that excessive silicon would form on the outer surface and/or within the pores of a porous support material.
  • a dilute silane-containing gas includes from 0.10 vol. % to 10 vol. % of a silane material (e.g., monosilane).
  • a dilute silane-containing gas includes from 0.25 vol. % to 8 vol. % of a silane material.
  • a dilute silane- containing gas includes from 0.50 vol. % to 6 vol. % of a silane material. In another embodiment, a dilute silane-containing gas includes from 0.50 vol. % to 5 vol. % of a silane material. In yet another embodiment, a dilute silane-containing gas includes from 0.50 vol. % to 4 vol. % of a silane material. In another embodiment, a dilute silane-containing gas includes from 0.5 vol. % to 3 vol. % of a silane material. In yet another embodiment, a dilute silane-containing gas includes from 0.75 vol. % to 3 vol. % of a silane material.
  • a dilute silane-containing gas includes from 0.75 vol. % to 2.5 vol. % of a silane material. In yet another embodiment, a dilute silane-containing gas includes from 0.75 vol. % to 2.0 vol. % of a silane material. In another embodiment, a dilute silane-containing gas includes from 1.0 vol. % to 2.0 vol. % of a silane material.
  • the reacting step (230) generally occurs concomitant to the contacting step (220), and includes reacting at least some of the copper metal with at least some of the silicon of the silane -material, thereby forming binary copper-silicon material.
  • the produced binary-copper silicon materials may be any of the binary copper-silicon materials described above.
  • the contacting step (220) and reacting step (230) may involve short residence time and/or dilute silane-containing materials to produce copper-rich copper silicides (e.g., Cu 5 Si) and/or copper-silicon solid solutions.
  • the contacting step (220) and reacting step (230) may involve longer residence times to produce silicon-rich copper silicides (e.g., Cu 3 Si).
  • the method may optionally include maintaining (225) the porous high-surface area material at a temperature of from 100°C to 350°C during the contacting (220) and reacting (230) steps (e.g., to control the reaction conditions and facilitate production of binary copper-silicon materials with limited by-products, such as excess silicon on the outer surfaces and/or within the pores of the porous high-surface area support).
  • the method comprises maintaining the porous high-surface area material at a temperature of from 100°C to 325°C during the contacting (220) and reacting (230) steps.
  • the method comprises maintaining the porous high-surface area material at a temperature of from 100°C to 300°C during the contacting (220) and reacting (230) steps.
  • the method comprises maintaining the porous high-surface area material at a temperature of from 100°C to 275°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 100°C to 250°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 100°C to 225°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 125°C to 250°C during the contacting (220) and reacting (230) steps.
  • the method comprises maintaining the porous high-surface area material at a temperature of from 150°C to 250°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 175°C to 250°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 175°C to 250°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 190°C to 210°C during the contacting (220) and reacting (230) steps.
  • the recovering step (240) generally comprises recovering a final product having binary copper-silicon material within the pores of the porous high-surface area material.
  • the final product generally includes from 0.01 to 80 wt. % Cu, and the final product generally realizes a final BET surface area that is from 1% to 99% of the initial BET surface area.
  • the final product comprises from 0.01 to 60 wt. % Cu.
  • the final product comprises from 0.01 to 40 wt. % Cu.
  • the final product comprises from 0.01 to 30 wt. % Cu.
  • the final product comprises from 0.01 to 20 wt. % Cu.
  • the final product comprises from 0.01 to 10 wt. % Cu.
  • the final product may comprise at least 0.05 wt. % Cu. In any of these embodiments, the final product may comprise at least 0.25 wt. % Cu. In any of these embodiments, the final product may comprise at least 0.50 wt. % Cu. In any of these embodiments, the final product may comprise at least 0.75 wt. % Cu. In any of these embodiments, the final product may comprise at least 1.0 wt. % Cu.
  • the final product generally comprises a final BET surface area that is from 1% to 99% of the initial BET surface area.
  • the final product comprises a final BET surface area that is at least 5% of the initial BET surface area.
  • the final product comprises a final BET surface area that is at least 10% of the initial BET surface area.
  • the final product comprises a final BET surface area that is at least 15% of the initial BET surface area.
  • the final product comprises a final BET surface area that is at least 20% of the initial BET surface area.
  • the final product comprises a final BET surface area that is at least 25% of the initial BET surface area.
  • the final product comprises a final BET surface area that is at least 30% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 35% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 40% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 45% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 50% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 55% of the initial BET surface area.
  • the final product comprises a final BET surface area that is at least 60% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 65% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 70% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 75% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 80% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 85% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 90% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 95% of the initial BET surface area.
  • FIG. 1 is a schematic illustration of one embodiment of a method for catalytically converting pollutants of an exhaust gas using a solid binary copper-silicon material.
  • FIG. 2 is a schematic illustration of one embodiment of a system for catalytically converting pollutants of an exhaust gas using a solid binary copper-silicon material.
  • FIG. 3 is a flow chart illustrating one embodiment of a method for producing solid binary copper- silicon materials located on surfaces of porous high-surface area materials.
  • FIG. 4 is a flow chart illustrating one embodiment of a method forming copper metal particles in pores of porous high-surface area materials.
  • FIG. 5 is a flow chart illustrating another embodiment of a method forming copper metal particles in pores of porous high-surface area materials.
  • FIG. 6 is a diagram illustrating various methods of infiltrating pores of porous high-surface area materials with copper precursor.
  • FIG. 7 is a flow chart illustrating one embodiment of a method of concerting copper metal particles to binary copper-silicon materials located within pores of porous high- surface area materials.
  • the gases used were 0 2 (Airgas) and a gas mix (hereafter referred to as EPA mix) comprising 12.26 vol.%> C0 2 , 0.7653 vol.%> CO, 397.4 ppmv (parts per million by volume) NO, 360.7 ppmv propane, and the balance N 2 (Airgas).
  • Reaction conversions were measured for CO oxidation (CO + 0 2 C0 2 ) and NO reduction (NO + CO -> N 2 + C0 2 and/or 2NO -> N 2 + 0 2 ) via GC-TCD (Gas Chromatography Thermal Conductivity Detection).
  • a 20 of sample of the reactor effluent gas was injected via 6-way valve into an Agilent 7890 Gas Chromatograph (GC) having a thermal conductivity detector (TCD). Separation of gasses in the GC was achieved via injection onto a ShinCarbon ST packed column (Restek, 4 m long, 2 mm i.d., 80-100 mesh carbon particle size).
  • the temperature program for the column to achieve separation of 0 2 , N 2 , NO and CO was: 70°C (3 minute hold) ramp to 200°C (ramped over 4 minutes) for a total runtime of 7 minutes.
  • the TCD peak area (Peak Area) of the CO peak and the NO peak were compared to their respective peak areas at room temperature (where no conversion occurs) (Ref. Peak Area). Given that the TCD detector has a linear response to each component in these concentration ranges, the conversion for each component can be calculated from (1- Peak Area/Ref. Peak Area) xl00%. At each new temperature the catalyst was allowed to reach steady state for at least 1 hour before data was collected. When changing gas flow rates at a given temperature, the catalyst was allowed to reach steady state for at least 10 minutes between measurements.
  • Cu 5 Si chunks (Alfa Aesar) were purchased and subsequently ball milled into a powder in a tungsten carbide vial with tungsten carbide balls in a 10: 1 weight ratio of balls to Cu 5 Si. The duration of milling was 1 hour. 0.89 g of the Cu 5 Si powder was loaded into a 1 ⁇ 4" o.d. quartz glass tube insert with a quartz glass wool plug (to retain the powder in the reactor, Chemglass) and loaded into the reactor as described in Example 1. The Cu 5 Si powder was
  • the reactor was configured to realize a gas residence time of 300 ms ⁇ 60 ms.
  • the catalyst was first conditioned at 500°C under a combination of 1 seem 0 2 flow and 10 seem EPA mix flow, and allowed to cool under N 2 flow to room temperature. The measurements taken at various gas flows and temperatures are shown in Table 2 and were carried out using the procedures described in Example 1.
  • Example 3 - Testing Of Conventional Pd Catalyst 0.43 g of as purchased 0.5 wt.% Pd on 3.2 mm alumina pellets (Alfa Aesar, batch number of B16Y031) were loaded into a 1 ⁇ 4" o.d. quartz glass tube insert that was then slid into the steel tube of a flow reactor for testing. The reactor was then purged with N 2 and heated to 500°C under a combined flow of 1 seem (standard cubic centimeters per minute) 0 2 (Airgas) and 10 seem EPA mix gas using a Lindberg/Blue 1" tube furnace.
  • the EPA mix gas consisted of 12.26 vol.% C0 2 , 0.7653 vol.% CO, 397.4 ppmv (parts per million by volume) NO, 360.7 ppmv propane, and the balance N 2 (Airgas). All gas flows to the reactor were controlled using Brooks mass flow controllers. After heating, the catalyst was allowed to cool to room temperature under 10 seem of N 2 flow. After cooling, the catalyst was exposed to 10 seem of EPA gas mix and 1 seem of 0 2 at various temperatures, as shown in Table 1. Reaction conversions were measured for propane oxidation (C 3 3 ⁇ 4 + 5 0 2 3 C0 2 + 4 H 2 0) via GC-TCD (Gas Chromatography Thermal Conductivity Detection).
  • a 20 of sample of the reactor effluent gas was injected via 6-way valve into an Agilent 7890 Gas Chromatograph (GC) having a thermal conductivity detector (TCD). Separation of gasses in the GC was achieved via injection onto a ShinCarbon ST packed column (Restek, 4 m long, 2 mm i.d., 80-100 mesh carbon particle size).
  • the temperature program for the column to achieve separation of 0 2 , N 2 , NO, CO, C0 2 and C 3 3 ⁇ 4 was: 70°C (2.15 minute hold) ramp to 280°C (ramped over 1.75 minutes), hold at 280°C for a 18.6 minutes for total runtime of 22.5 minutes.
  • the TCD peak area (Peak Area) of the propane peak was compared to the propane peak area at room temperature (where no conversion occurs) (Ref. Peak Area). Given that the TCD detector has a linear response to propane over the range of concentrations tested, the conversion for each component can be calculated from (1- Peak Area/Ref. Peak Area) xl00%. At each new temperature the catalyst was allowed to reach steady state for at least 30 minutes before data was collected.
  • Cu 5 Si chunks (Alfa Aesar) were purchased and subsequently ball milled into a powder in a tungsten carbide vial with tungsten carbide balls in a 10: 1 weight ratio of balls to Cu 5 Si. The duration of milling was 1 hour. 1.11 g of the Cu 5 Si powder was loaded into a 1 ⁇ 4" o.d. quartz glass tube insert with a quartz glass wool plug (to retain the powder in the reactor, Chemglass) and loaded into the reactor as described in Example 1. The Cu 5 Si powder was
  • the reactor was configured to realize a gas residence time of 300 ms ⁇ 60 ms.
  • the catalyst was first conditioned at 500°C under a combination of 1 seem 0 2 flow and 10 seem EPA mix flow, and allowed to cool under N 2 flow to room temperature as described in Example 1. The measurements taken at various temperatures are shown in Table 4 and were carried out using the procedures described in Example 1.
  • Cu powder (99%, ⁇ 75 ⁇ ; Sigma- Aldrich) and Si powder (at least 99.999%; Hemlock Semiconductor) were purchased.
  • An agate mortar and pestle was used to grind 3.5184 g (55.364 mmole) of the Cu powder together with 0.5072 g (18.06 mmole) of the Si powder thereby forming a Cu/Si powder mixture.
  • This mixture was then loaded into a graph- foil lined graphite punch and die set (40mm x 20mm graphite die with 20mm x 30mm graphite punches). The punch and die set was then loaded into the Spark Plasma Sintering (SPS) chamber of a Pulsed Electric Current Sintering system (Thermal Technology, LLC, Model 10-4).
  • SPS Spark Plasma Sintering
  • the SPS chamber was evacuated to a pressure ⁇ 2E-3 torr. Next, a uniaxial pressure of 1 MPa was applied to the mixture via the SPS chamber. The mixture in the SPS chamber was then heated at 200 °C » min-l to 300 °C and held for five minutes. The temperature of the SPS die was monitored using a thermocouple positioned directly under the sample. The pressure in the SPS chamber was then increased to 60 MPa at 20MPa » min-l . The temperature in the SPS chamber was then increased to 700 °C at 200 °C » min-l and held for 2h. The contents of the SPS chamber were then cooled as quickly as possible to room temperature. Thus, an essentially phase-pure Cu 3 Si solid binary copper silicide catalyst material was formed.
  • the Cu 3 Si solid binary copper silicide catalyst material was prepared for catalysis via ball milling for 4h using three WC spheres, thereby forming an essentially phase-pure Cu 3 Si solid binary copper silicide catalyst powder.
  • Powder X-ray diffraction (XRD) results show the Cu 3 Si powder comprises essentially phase-pure Cu 3 Si.
  • the powder X-ray diffraction patterns were collected in Bragg-Brentano geometry from 10 to 80° 2 ⁇ in 0.02° increments at 0.4 second per step with a Cu anode operating at 40 kV and 44 mA.
  • An open height limiting slit, 0.6 mm divergence slit, 22.92 mm scattering slit, 37.77 mm receiving slit were used, and intensity data were collected with a high speed detector.
  • Example 5 Details of Example 5 - NO And CO Conversion Using Essentially Phase-Pure
  • Cu wire (99.999%, 2.0mm diameter; Sigma-Aldrich) and Si pieces (at leatst 99.99%, -lOmm pieces; Hemlock Semiconductor) were purchased.
  • a cooled copper crucible was then loaded with 4.57 g (71.9 mmole) of the Cu wire and 0.40 g (72 mmole) of the Si pieces.
  • the loaded copper crucible was placed into the chamber of an arc melter (MRF model SA200). The chamber was then purged with Argon gas.
  • the Cu wire and Si pieces in the copper crucible were then melted together for -60s using an arc generated from a ceriated-tungsten electrode.
  • the catalyst was then re-melted an additional three times using the same procedure, thereby forming an essentially phase-pure Cu 5 Si solid binary copper silicide catalyst material.
  • the Cu 5 Si solid binary copper silicide catalyst material was prepared for catalysis via ball milling for 4h using three WC spheres, thereby forming an essentially phase-pure Cu 5 Si solid binary copper silicide catalyst powder.
  • Powder X-ray diffraction (XRD) results show the Cu 5 Si powder comprises essentially phase-pure Cu 5 Si.
  • the powder X-ray diffraction patterns were collected using the procedures described in Example 5.
  • Cu powder (99%, ⁇ 75 ⁇ ; Sigma-Aldrich) and Si powder (at least 99.999%; Hemlock Semiconductor) were purchased.
  • a WC-lined steel milling vial was charged with three WC spheres, 4.8384 g (76.135 mmole) of the Cu powder, and 0.1662 g (5.917 mmole) of the Si powder.
  • the Cu and Si powders were milled together for 60min thereby forming a Cu/Si powder mixture.
  • This mixture was then Spark Plasma Sintered in a graph-foil lined graphite punch and die set using the procedures described in Example 5, thereby forming an essentially phase-pure Cu-Si solid solution catalyst material.
  • the Cu-Si solid solution catalyst material was prepared for catalysis by ball milling for lh using three WC spheres, thereby forming a Cu-Si solid solution catalyst powder.
  • Powder XRD results show a slight shift in 2 ⁇ that is indicative of Si substitution into the Cu lattice.
  • the powder X-ray diffraction patterns were collected using the procedures described in Example 5.
  • Example 8 Preparation of Binary Copper-Silicon Materials on High- Surface Area Porous Support Materials
  • Cu 3 Si impregnated ⁇ - ⁇ 1 2 0 3 (Cu 3 Si/y-Al 2 0 3 ) samples were prepared via 1) H 2 reduction and 2) SiH 4 silicidation of CuO impregnated ⁇ - ⁇ 1 2 0 3 (CuO/y-Al 2 0 3 ).
  • CuO/y-Al 2 0 3 samples were prepared using conventional wet impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of ⁇ - ⁇ 1 2 0 3 were dried in air at 550 °C for 4 h.
  • Cu 3 Si/Y-Al 2 0 3 samples were prepared by loading 3.9990 g CUO/Y-A1 2 0 3 (10.7 wt% Cu) into a 1 ⁇ 2" o.d. stainless steel flow reactor. The reactor was then evacuated with a roughing pump to a pressure ⁇ 50 mtorr. The reactor was then filled with Ar and heated to 500 °C (10 °C/min ramp) under 100 standard cubic centimeters per minute (seem) Ar gas flow using a Lindberg/Blue 1" tube furnace. All gas flows were controlled using MKS mass flow controllers. The reactor effluent was monitored using an RGA.
  • the CuO/y-Al 2 0 3 was reduced in 1% H 2 in Ar (5 seem H 2 , 500 seem Ar) for 55 min, then 5% H 2 in Ar (5 seem H 2 , 95 seem Ar) for 15 min, then 50 seem H 2 for 10 min.
  • the reactor was cooled under 50 seem H 2 flow to 200 °C.
  • the H 2 was turned off and 100 seem 1% SiH 4 in H 2 was flowed for 20.25 h.
  • 1% SiH 4 in H 2 was turned off, and the reactor was cooled to room temperature under 50 seem H 2 . An amount of 4.0391 g product was isolated.
  • Powder XRD analysis shows the crystalline composition of this material consists of Cu 3 Si and (Al 2 0 3 )5. 3333 .
  • the gases used were 0 2 (Airgas) and a gas mix (hereafter referred to as EPA mix) comprising 12.26 vol.% C0 2 , 0.7653 vol.% CO, 397.4 ppmv (parts per million by volume) NO, 360.7 ppmv propane, and the balance N 2 (Airgas).
  • Reaction conversions were measured for CO oxidation (CO + 0 2 C0 2 ) and NO reduction (NO + CO -> N 2 + C0 2 and/or 2NO -> N 2 + 0 2 ) via GC-TCD (Gas Chromatography Thermal Conductivity Detection).
  • a 20 of sample of the reactor effluent gas was injected via 6-way valve into an Agilent 7890 Gas Chromatograph (GC) having a thermal conductivity detector (TCD). Separation of gasses in the GC was achieved via injection onto a ShinCarbon ST packed column (Restek, 4 m long, 2 mm i.d., 80-100 mesh carbon particle size).
  • the temperature program for the column to achieve separation of 0 2 , N 2 , NO and CO was: 70°C (3 minute hold) ramp to 200°C (ramped over 4 minutes) for a total runtime of 7 minutes.
  • the TCD peak area (Peak Area) of the CO peak and the NO peak were compared to their respective peak areas when flowing through a bypass line that did not pass the gas mixture over the catalyst, but instead passed it through a blank glass tube at room temperature (where no conversion occurs) (Ref. Peak Area).
  • the conversion for each component can be calculated from (1- Peak Area/Ref. Peak Area) xl00%.
  • the catalyst was allowed to reach steady state for at least 30 minutes before data was collected.
  • the catalyst was allowed to reach steady state for at least 10 minutes between measurements. The results of this test are shown in Table 8.
  • the CU3S1/AI2O3 catalyst shows a lower conversion of NO and CO (i.e., the catalyst deactivates and requires a higher temperature to achieve a given conversion).
  • the 100% NO conversion temperature reaches a steady state level after 3 - 4 days and is achieved at 150 - 180 °C.
  • the 100% CO conversion temperature reaches a steady state level after 3 - 4 days and is achieved at 120 - 150 °C.
  • the catalyst can be regenerated to full activity by raising the catalyst temperature for a brief period (1 hour) to 500 °C. After cooling to the reaction temperature, the catalyst demonstrates the same level of conversion as fresh catalyst shown in Table 8.
  • Reaction conversions for the as prepared CU3S1 on AI2O3 catalyst were measured for propane oxidation (C3H8 + 5 O2 3 CO2 + 4 3 ⁇ 40) via GC-TCD (Gas Chromatography Thermal Conductivity Detection).
  • GC-TCD Gas Chromatography Thermal Conductivity Detection
  • a 20 of sample of the reactor effluent gas was injected via 6-way valve into an Agilent 7890 Gas Chromatograph (GC) having a thermal conductivity detector (TCD). Separation of gasses in the GC was achieved via injection onto a ShinCarbon ST packed column (Restek, 4 m long, 2 mm i.d., 80-100 mesh carbon particle size).
  • the temperature program for the column to achieve separation of 0 2 , N 2 , NO, CO, C0 2 and C 3 3 ⁇ 4 was: 70°C (2.15 minute hold) ramp to 280°C (ramped over 1.75 minutes), hold at 280°C for a 18.6 minutes for total runtime of 22.5 minutes.
  • the TCD peak area (Peak Area) of the propane peak was compared to the propane peak area at room temperature (where no conversion occurs) (Ref. Peak Area). Given that the TCD detector has a linear response to propane over the range of concentrations tested, the conversion for each component can be calculated from (1- Peak Area/Ref. Peak Area) xl00%. At each new temperature the catalyst was allowed to reach steady state for at least 30 minutes before data was collected. The results of this test are shown in Table 9.
  • the propane conversion is stable over time.
  • the catalyst does not demonstrate any deactivation for this reaction.
  • a quartz glass sample tube that is sealed at one end was filled with a small amount (0.2917 g) of the as-prepared Cu 3 Si on A1 2 0 3 catalyst sample.
  • the tube was then evacuated on a Schlenk line to 50 miUitorr.
  • the sample was then taken through a cycle of backfilling with argon, and evacuating to 50 miUitorr a total of 3 times.
  • the glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon.
  • the sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed.
  • XRD analysis indicated the presence of crystalline Cu and A1 2 0 3 and CuO (from oxidation of Cu after exposure to air on opening the vial), indicating that the Si had diffused out of the Cu 3 Si and into the A1 2 0 3 support at high temperatures.
  • Cu 3 Si was impregnated into lanthana doped ⁇ - ⁇ 1 2 0 3 support (Cu 3 Si/La- A1 2 0 3 ) via H 2 reduction and subsequent SiH 4 silicidation of CuO impregnated La-Al 2 0 3 .
  • the samples were prepared by conventional incipient wetness impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of support were dried in air at 550 °C for 4 h. 15.50 mL of a 2.16 M aqueous solution of Cu(N0 3 ) 2 '3H 2 0 was added dropwise while stirring to 19.99 g of dried La-Al 2 0 3 powder.
  • the catalyst After several days of flowing EPA gas over the catalyst, the catalyst shows a lower conversion of NO and CO (i.e., the catalyst deactivates and requires a higher temperature to achieve a given conversion).
  • the 100% NO conversion temperature reaches a steady state level after 5 - 6 days and is achieved at 170 - 190 C.
  • the 100% CO conversion temperature reaches a steady state level after 6 - 7 days and is achieved at 140 - 170 C.
  • the catalyst can be regenerated to full activity by raising the catalyst temperature for a brief period (1 hour) to 500°C. After cooling to the reaction temperature, the catalyst demonstrates the same level of conversion as fresh catalyst.
  • a quartz glass sample tube that is sealed at one end was filled with a small amount (0.1089 g) of the as-prepared Cu 3 Si on La-Al 2 0 3 sample.
  • the tube was then evacuated on a Schlenk line to 50 millitorr.
  • the sample was then taken through a cycle of backfilling with argon, and evacuating to 50 millitorr a total of 3 times.
  • the glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon.
  • the sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed. XRD analysis indicated the presence of Cu and no copper silicides could be detected, indicating that the Si had diffused out of the Cu 3 Si and into the La-Al 2 0 3 support.
  • Cu 3 Si was impregnated into SIRALOX 10 support (Cu 3 Si/S-10) via H 2 reduction and subsequent SiH 4 silicidation of CuO impregnated SIRALOX 10.
  • the samples were prepared by conventional incipient wetness impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of support were dried in air at 550 °C for 4 h. 14.58 mL of a 2.31 M aqueous solution of Cu(N0 3 ) 2 3H 2 0 was added dropwise while stirring to 20.10 g of dried SIRALOX 10 powder. The mixture was then placed in a vacuum oven (75 torr) and dried overnight at 120 °C.
  • a quartz glass sample tube that is sealed at one end was filled with a small amount (0.2016 g) of the as-prepared Cu 3 Si on SIRALOX 10 support sample.
  • the tube was then evacuated on a Schlenk line to 50 millitorr.
  • the sample was then taken through a cycle of backfilling with argon, and evacuating to 50 millitorr a total of 3 times.
  • the glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon.
  • the sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed. XRD analysis indicated the presence of Cu and no copper silicides could be detected, indicating that the Si had diffused out of the Cu 3 Si and into the SIRALOX 10 support.
  • Cu 3 Si was impregnated into SIRALOX 40 support (Cu 3 Si/S-40) via H 2 reduction and subsequent S1H 4 silicidation of CuO impregnated SIRALOX 40.
  • the samples were prepared by conventional wet impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of support were dried in air at 550 °C for 4 h. An amount of 20.035 g of dried SIRALOX 40 powder was immersed in 21.50 mL of a 1.92 M aqueous solution of Cu(N0 3 ) 2 -3H 2 0. The mixture was then placed in a vacuum oven (75 torr) and dried overnight at 120 °C.
  • a quartz glass sample tube that is sealed at one end was filled with a small amount (0.2054 g) of the as-prepared Cu 3 Si on SIRALOX 40 sample.
  • the tube was then evacuated on a Schlenk line to 50 millitorr.
  • the sample was then taken through a cycle of backfilling with argon, and evacuating to 50 millitorr a total of 3 times.
  • the glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon.
  • the sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed. XRD analysis indicated the presence of crystalline, Cu 7 Si and a small amount of CU0. S10.1, indicating that the Si remains associated with the copper on this support when exposed to high temperatures.
  • Cu 3 Si was impregnated into SiC support (Cu 3 Si/SiC) via H 2 reduction and subsequent SiH 4 silicidation of CuO impregnated SiC.
  • the samples were prepared by conventional wet impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of support were dried in air at 550 °C for 4 h. An amount of 20.022 g of dried SiC powder was immersed in 40 mL of a 0.874 M aqueous solution of Cu(N0 3 ) 2 -3H 2 0. The mixture was then placed in a vacuum chamber (75 torr) for 15 min to accelerate the impregnation.
  • the impregnated support was isolated via vacuum filtration, and dried overnight at 120 °C in a vacuum oven (75 torr). After drying, Cu loading was determined gravimetrically to be 10.0 wt% Cu.
  • 3.997 g of sample was loaded into a 1 ⁇ 2" o.d. glass tube flow reactor and heated at 10 °C/min ramp under 50 seem air flow to 450 °C, where it was held and calcined for 5 hours. All gas flows were controlled with MKS mass flow controllers and the furnace used was a Lindberg/Blue 1" tube furnace. The reactor was then purged under argon flow at 495 seem and ramped at 10 °C/min to 500 °C.
  • a quartz glass sample tube that is sealed at one end was filled with a small amount (0.3010 g) of the as-prepared Cu 3 Si on SiC sample.
  • the tube was then evacuated on a Schlenk line to 50 millitorr.
  • the sample was then taken through a cycle of backfilling with argon, and evacuating to 50 millitorr a total of 3 times.
  • the glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon.
  • the sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed.
  • XRD analysis indicated the presence of crystalline Cu 3 Si and Cu 5 Si, indicating that the Si remains associated with the copper on this support.
  • a further test with 0.3007 g of the as-prepared Cu 3 Si on SiC sample sealed in a glass tube as described above and placed in a muffle furnace at 500°C for 168 hours, showed no further change.
  • XRD also indicated the presence of Cu 3 Si and Cu 5 Si, so this SiC support appears to be able to support copper silicides with high temperature stability.
  • a third test was undertaken with 0.2928 g of the as- prepared Cu 3 Si on SiC sample sealed in a glass tube as described above and placed in a muffle furnace at 1000°C for 87 hours.
  • XRD indicated the presence of Cu 3 Si and Cu 5 Si, demonstrating stability at very high temperatures.
  • Cu 3 Si was impregnated into Si 3 N 4 support (Cu 3 Si/Si 3 N 4 ) via H 2 reduction and subsequent SiH 4 silicidation of CuO impregnated Si 3 N 4 .
  • the samples were prepared by conventional incipient wetness impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of support were dried in air at 550 °C for 4 h. 11.50 mL of a 0.813 M aqueous solution of ⁇ ( ⁇ 0 3 ) 2 ⁇ 3 ⁇ 2 0 was added dropwise while stirring to 5.873 g of dried Si 3 N 4 powder. The mixture was then placed in a vacuum oven (75 torr) and dried overnight at 120 °C.
  • a quartz glass sample tube that is sealed at one end was filled with a small amount (0.1980 g) of the as-prepared Cu 3 Si and Si 3 N 4 sample.
  • the tube was then evacuated on a Schlenk line to 50 millitorr.
  • the sample was then taken through a cycle of backfilling with argon, and evacuating to 50 millitorr a total of 3 times.
  • the glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon.
  • the sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed. XRD analysis indicated the presence of crystalline Cu 3 Si and Cu 4 Si, indicating that the Si remains associated with the copper on this support when exposed to high temperatures.
  • Cu 3 Si was impregnated into Davisil silica support (Cu 3 Si/Si0 2 ) via H 2 reduction and subsequent SiH 4 silicidation of CuO impregnated Si0 2 .
  • the samples were prepared by conventional incipient wetness impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of support were dried in air at 550 °C for 4 h. 14.84 mL of a 2.16 M aqueous solution of Cu(N0 3 )2-3H 2 0 was added dropwise while stirring to 20.10 g of dried Si0 2 powder. The mixture was then placed in a vacuum oven (75 torr) and dried overnight at 120 °C.
  • a quartz glass sample tube that is sealed at one end was filled with a small amount (0.1991 g) of the as-prepared Cu 3 Si on Si0 2 sample.
  • the tube was then evacuated on a Schlenk line to 50 millitorr.
  • the sample was then taken through a cycle of backfilling with argon, and evacuating to 50 millitorr a total of 3 times.
  • the glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon.
  • the sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed. XRD analysis indicated the presence of crystalline, Cu 3 Si and Cu 5 Si, indicating that the Si remains associated with the copper on this support when exposed to high temperatures.
  • a portion of the sample (a bead) was analyzed by SEM/EDS and found to have a silicon shell and a copper/alumina core.
  • the silane had decomposed to Si and blocked the pores of the support, forming a shell and making the copper in the core inaccessible for further reaction.

Abstract

New solid binary copper-silicon material catalysts for emissions control and methods of making and using the same are disclosed. The methods may include combusting a substance, thereby producing an exhaust gas having a pollutant therein. The pollutant may comprise at least one of CO, NOx, plain hydrocarbons and oxygenated hydrocarbons. The exhaust gas may be contacted with a solid binary copper-silicon material, thereby catalytically converting at least a portion of the pollutant into a product. The methods may include methods of producing binary copper-silicon materials loaded on a porous high-surface area material.

Description

SOLID BINARY COPPER- SILICON MATERIAL CATALYSTS FOR EMISSIONS
CONTROL
BACKGROUND
[001] Combustion engines, including those of passenger cars, may emit pollutants including CO, NOx, and hydrocarbons. The United States Environmental Protection Agency ("EPA") estimates that on an annual basis the average passenger car emits 248.46 lb. of CO, 18.32 lb. of NOx, and 28.47 lb. of total hydrocarbons ("Average Annual Emissions and Fuel Consumption for Gasoline -Fueled Passenger Cars and Light Trucks" (EPA420-F-08-024)).
SUMMARY OF THE DISCLOSURE
[002] Broadly, the present patent application relates to catalytically converting pollutants of an exhaust gas using solid binary copper-silicon materials. The solid binary copper-silicon materials may facilitate catalytically converting one or more of CO, NOx, plain hydrocarbons, and oxygenated hydrocarbons, as defined below. Such solid binary copper- silicon materials may thus find use in an emissions control device, such as a mobile emissions control device or a stationary emissions control device, as defined below.
[003] For instance, and with reference now to FIG. 1, a method may include combusting a substance (10), thereby producing an exhaust gas having a pollutant therein (e.g., at least one of CO, NOx and hydrocarbons (e.g. plain hydrocarbons and/or oxygenated hydrocarbons, as defined below)). The method may further comprise contacting the exhaust gas with a solid binary copper-silicon material (20) and, concomitantly, catalytically converting (30) at least a portion of the pollutant into a product via the solid binary copper-silicon material.
I. Binary Copper-Silicon Materials and Catalytic Conversion
[004] As used herein, "catalytically convert" and the like means to chemically react at least some amount of a pollutant via a catalyst. As used herein, "catalyst" and the like means a material that lowers the activation energy of a chemical reaction without being consumed by the reaction. Thus, the solid binary copper-silicon catalyst materials described herein are not consumed during their participation in converting the pollutants. Also, since the solid binary copper-silicon materials catalytically convert gas phase materials, the solid binary copper-silicon materials are a heterogeneous catalyst. As used herein, "heterogeneous catalyst" means a catalyst that is a different phase of matter than the pollutant.
[005] The temperature of the solid binary copper- silicon material catalysts may play a role in the relative efficiency of the solid binary copper-silicon material catalysts. For example, low temperatures may result in lower conversion rates of a pollutant to a non- pollutant. In one embodiment, the solid binary copper-silicon materials may realize a light- off temperature for a given pollutant. As used herein, "light-off temperature" and the like means the temperature of a solid binary copper-silicon material catalyst at which at least 50 molar % of a particular pollutant is catalytically converted to a non-pollutant. A solid binary copper-silicon material catalyst may realize different light-off temperatures for different pollutants.
[006] The solid binary copper-silicon materials may realize low light-off temperatures (e.g., below a normal operating exhaust gas temperature of an automobile, such as 400 °C to 600°C). For example, the solid binary copper-silicon materials may realize a light-off temperature for CO of about 170°C when the residence time of the pollutant is about 300 ms (milliseconds) and the specific surface area of the solid binary copper-silicon materials is about 0.11 m /g and the mass of the solid binary copper-silicon materials is about 0.89 g. As another example, the solid binary copper-silicon materials may realize a light-off temperature for NO of about 140°C and at the above conditions (e.g., the residence time, specific surface area and mass of solid binary copper-silicon materials noted above). As yet another example, the solid binary copper-silicon materials may realize a light-off temperature for propane of about 300°C and at the above conditions. When the solid-binary copper-silicon materials are utilized with a high-surface area support, as described below, even lower light-off temperatures may be realized. For instance, solid binary copper-silicon materials located on a high-surface area support may realize a light-off temperature for NO as low as ambient temperature (e.g., about 25°C) and at the above conditions (e.g., the residence time and mass of solid binary copper-silicon materials noted above).
[007] In another approach, the solid binary copper-silicon materials may catalytically convert at least some of at least one pollutant at temperatures other than the light-off temperature(s) (e.g. at temperatures lower than a light-off temperature). In one embodiment, when a pollutant is CO, the solid binary copper-silicon materials may convert at least 1 molar % of the CO to C02 at a temperature of from about 50°C to about 200°C when the residence time of the pollutant is about 300 ms (milliseconds) and the specific surface area of the solid binary copper-silicon materials is about 0.11 m /g and the mass of the solid binary copper- silicon materials is about 0.89 g. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the CO to C02 at a temperature of not greater than 190°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the CO to C02 at a temperature of not greater than 180°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the CO to C02 at a temperature of not greater than 170°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the CO to C02 at a temperature of not greater than 160°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the CO to C02 at a temperature of not greater than 150°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the CO to C02 at a temperature of not greater than 140°C and at the above conditions. In some embodiments, the solid binary copper- silicon materials may convert at least 20 molar % of the CO to C02. In some embodiments, the solid binary copper-silicon materials may convert at least 30 molar % of the CO to C02. In some embodiments, the solid binary copper-silicon materials may convert at least 40 molar % of the CO to C02. In some embodiments, the solid binary copper-silicon materials may convert at least 50 molar % of the CO to C02. In some embodiments, the solid binary copper-silicon materials may convert at least 75 molar % of the CO to C02. In some embodiments, the solid binary copper-silicon materials may convert at least 85 molar % of the CO to C02. In some embodiments, the solid binary copper-silicon materials may convert at least 95 molar % of the CO to C02. In some embodiments, the solid binary copper- silicon materials may convert at least 98 molar % of the CO to C02. When solid-binary copper- silicon materials are utilized with a high-surface area support, as described below, the solid- binary copper-silicon materials are utilized with a high-surface area support may realize any of the above described CO molar conversion amounts at from 50° to 200°C and at the above conditions.
[008] As another example, when a pollutant is NOx, the solid binary copper-silicon materials may convert at least 1 molar % of the NOx to N2 at a temperature of from about 50°C to about 200°C when the residence time of the pollutant is about 300 ms and the specific surface area of the solid binary copper-silicon materials is about 0.11 m /g and the mass of the solid binary copper-silicon materials is about 0.89 g. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the NOx to N2 at a temperature of not greater than 180°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the NOx to N2 at a temperature of not greater than 160°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the NOx to N2 at a temperature of not greater than 140°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the NOx to N2 at a temperature of not greater than 120°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the NOx to N2 at a temperature of not greater than 110°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the NOx to N2 at a temperature of not greater than 100°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the NOx to N2 at a temperature of not greater than 90°C and at the above conditions. In some embodiments, the solid binary copper-silicon materials may convert at least 20 molar % of the NOx to N2. In some embodiments, the solid binary copper-silicon materials may convert at least 30 molar % of the NOx to N2. In some embodiments, the solid binary copper-silicon materials may convert at least 40 molar % of the NOx to N2. In some embodiments, the solid binary copper- silicon materials may convert at least 50 molar % of the NOx to N2. In some embodiments, the solid binary copper-silicon materials may convert at least 75 molar % of the NOx to N2. In some embodiments, the solid binary copper-silicon materials may convert at least 85 molar % of the NOx to N2.
[009] When solid-binary copper-silicon materials are utilized with a high-surface area support, as described below, the solid-binary copper-silicon materials are utilized with a high- surface area support may realize any of the above described NOx molar conversion amounts at from 50° to 200°C and at the above conditions (i.e., when the residence time of the pollutant is about 300 ms and the mass of the solid binary copper- silicon materials is about 0.89 g). In fact, when the solid-binary copper-silicon materials are utilized with a high- surface area support, as described below, the conversion of NOx to N2 may be completed at lower temperatures and/or with higher conversion rates. In one embodiment, solid binary copper-silicon materials located on a high-surface area support may convert at least 10 molar % of the NOx to N2 at a temperature of not greater than 80°C at the above conditions. In one embodiment, solid binary copper-silicon materials located on a high-surface area support may convert at least 10 molar % of the NOx to N2 at a temperature of not greater than 70°C at the above conditions. In one embodiment, solid binary copper-silicon materials located on a high-surface area support may convert at least 10 molar % of the NOx to N2 at a temperature of not greater than 60°C at the above conditions. In one embodiment, solid binary copper- silicon materials located on a high-surface area support may convert at least 10 molar % of the NOx to N2 at a temperature of not greater than 50°C at the above conditions. In one embodiment, solid binary copper-silicon materials located on a high-surface area support may convert at least 10 molar % of the NOx to N2 at a temperature of not greater than 40°C at the above conditions. In one embodiment, solid binary copper-silicon materials located on a high-surface area support may convert at least 10 molar % of the NOx to N2 at a temperature of not greater than 30°C at the above conditions. In one embodiment, solid binary copper- silicon materials located on a high-surface area support may convert at least 10 molar % of the NOx to N2 at at about ambient temperature at the above conditions. In some embodiments, solid binary copper-silicon materials located on a high-surface area support may convert at least 20 molar % of the NOx to N2. In some embodiments, solid binary copper-silicon materials located on a high- surface area support may convert at least 30 molar % of the NOx to N2. In some embodiments, solid binary copper- silicon materials located on a high-surface area support may convert at least 40 molar % of the NOx to N2. In some embodiments, solid binary copper-silicon materials located on a high-surface area support may convert at least 50 molar % of the NOx to N2. In some embodiments, solid binary copper-silicon materials located on a high-surface area support may convert at least 60 molar % of the NOx to N2. In some embodiments, solid binary copper- silicon materials located on a high-surface area support may convert at least 70 molar % of the NOx to N2. In some embodiments, solid binary copper-silicon materials located on a high-surface area support may convert at least 80 molar % of the NOx to N2. In some embodiments, solid binary copper-silicon materials located on a high-surface area support may convert at least 90 molar % of the NOx to N2. In some embodiments, solid binary copper- silicon materials located on a high-surface area support may convert at least 95 molar % of the NOx to N2. In some embodiments, solid binary copper-silicon materials located on a high-surface area support may convert at least 99 molar % of the NOx to N2. In some embodiments, solid binary copper-silicon materials located on a high-surface area support may convert at least 99.99 molar % of the NOx to N2.
[0010] As yet another example, when a pollutant includes a plain hydrocarbon, the solid binary copper-silicon materials may convert at least 1 molar % of the plain hydrocarbon to water and/or C02 at a temperature of from about 200°C to about 350°C when the residence time of the pollutant is about 300 ms and the specific surface area of the solid binary copper- silicon materials is about 0.11 m /g and the mass of the solid binary copper-silicon materials is about 1.11 g. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the plain hydrocarbon to water and/or C02 at a temperature of not greater than 325°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the plain hydrocarbon to water and/or C02 at a temperature of not greater than 300°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the plain hydrocarbon to water and/or C02 at a temperature of not greater than 275°C and at the above conditions. In one embodiment, the solid binary copper-silicon materials may convert at least 10 molar % of the plain hydrocarbon to water and/or C02 at a temperature of not greater than 250°C and at the above conditions. In some embodiments, the solid binary copper-silicon materials may convert at least 20 molar % of the plain hydrocarbon to water and/or C02. In some embodiments, the solid binary copper-silicon materials may convert at least 30 molar % of the plain hydrocarbon to water and/or C02. In some embodiments, the solid binary copper-silicon materials may convert at least 40 molar % of the plain hydrocarbon to water and/or C02. In some embodiments, the solid binary copper-silicon materials may convert at least 50 molar % of the plain hydrocarbon to water and/or C02. In some embodiments, the solid binary copper-silicon materials may convert at least 75 molar % of the plain hydrocarbon to water and/or C02. In some embodiments, the solid binary copper-silicon materials may convert at least 95 molar % of the plain hydrocarbon to water and/or C02. When solid-binary copper-silicon materials are utilized with a high-surface area support, as described below, the solid-binary copper-silicon materials are utilized with a high-surface area support may realize any of the above described plain hydrocarbon molar conversion amounts at from 200° to 350°C and at the above conditions.
[0011] The solid binary copper-silicon materials (with or without a high-surface area support) may also catalytically convert pollutants of an exhaust gas at higher temperatures. In one approach, the exhaust gas is from an internal combustion engine. In one embodiment, the internal combustion engine is a gasoline-fueled internal combustion engine. In these embodiments, the solid binary copper-silicon materials catalytically convert pollutants at normal operating exhaust gas temperatures of the gasoline-fueled internal combustion engine, such as from about 400°C to about 600°C. In another embodiment, the internal combustion engine is a diesel-fueled internal combustion engine. In these embodiments, the solid binary copper-silicon materials may catalytically convert pollutants at normal operating exhaust gas temperatures of the diesel-fueled internal combustion engine, such as from about 200°C to about 400°C.
[0012] In additional embodiments, the solid binary copper- silicon materials (with or without a high-surface area support) may catalytically convert pollutants of an exhaust gas at high operating temperatures of an engine. Thus, the solid binary copper-silicon materials may catalytically convert pollutants of an exhaust gas at a temperature from about 50°C to about 1100°C. In one embodiment, the solid binary copper-silicon materials may catalytically convert pollutants of an exhaust gas at a temperature from about 80°C to about 900°C. In one embodiment, the solid binary copper-silicon materials may catalytically convert pollutants of an exhaust gas at a temperature from about 100°C to about 600°C. In one embodiment, the solid binary copper-silicon materials may catalytically convert pollutants of an exhaust gas at a temperature from about 300°C to about 600°C. In other embodiments, the solid binary copper-silicon materials may catalytically convert pollutants of an exhaust gas at a temperature from about 600°C to about 1100°C.
[0013] As noted above, and with continued reference to FIG. 1, the pollutants may be catalytically converted via the solid binary copper- silicon materials. When the pollutant includes CO, the catalytically converting may include catalytically oxidizing the CO into C02 (e.g., CO + 02 C02). When the pollutant includes NOx, the catalytically converting may include catalytically reducing the NOx into N2 (e.g., NO + CO -» N2 + C02 and/or 2NO -» N2 + 02). When the pollutant includes plain hydrocarbons, the catalytically converting may include catalytically oxidizing the plain hydrocarbons into at least one of C02 and H20 (e.g., C3H8 + 5 02 3 C02 + 4 H20). When the pollutant includes oxygenated hydrocarbons, the catalytically converting may include catalytically oxidizing the oxygenated hydrocarbons into at least one of C02 and H20 (e.g., C2H60 + 3 02 -> 2 C02 + 3 H20).
[0014] As noted above, the method may include combusting (10) the substance, thereby producing the exhaust gas. The method may further comprise flowing (14) the exhaust gas from the internal combustion engine to an emission control device that includes the solid binary copper- silicon material (with or without a high- surface area support). As used herein, "combusting" and the like means burning a substance in the presence of oxygen. As used herein, "exhaust gas" and the like means a gas that is produced as a result of burning a substance in the presence of oxygen, i.e., combusting. An exhaust gas may include gaseous forms of at least one pollutant, such as, for example, CO, NOx, plain hydrocarbons, and/or oxygenated hydrocarbons. An exhaust gas may also include gaseous forms of H2, H20, C02, and 02, among others. An exhaust gas may also include some amount of entrained particulate matter (e.g., soot) and/or some amount of entrained liquid (e.g., water droplets), among others. Sources of exhaust gas(es) include internal combustion engines (e.g., gasoline and/or diesel engines), external combustion engines (e.g., coal or gas fired power plants; steam engines), and/or chemical processing facilities (e.g., oil refineries).
[0015] As noted above, the catalytically converting is completed using a solid binary copper-silicon material. As used herein, "solid binary copper-silicon material" and the like means a solid (i.e, not a liquid or a gas) material that includes at least one of (a) a binary copper silicide and (b) a copper-silicon solid solution. As used herein, "binary copper silicide" and the like means an intermetallic compound of the formula CuxSiy, where X is a positive real number, where Y is a positive real number, and where the ratio of X to Y is such that a silicide may be formed. Typically, the ratio of "X" to "Y" is from about 3: 1 to about 9: 1. As used herein, "copper-silicon solid solution" and the like means a solid solution comprised of (and sometimes consisting essentially of) copper and at least some silicon, where the solid solution comprises not greater than 12 at% silicon. In one embodiment, the solid binary copper silicide material includes at least some Cu5Si (also known as "Cuo.83Sio.17"). In some embodiments, the solid binary copper silicide material includes at least some Cu3Si. In some embodiments, the solid binary copper silicide material includes at least some and Cui5Si4 (also known as "Cu3.72Si"). In some embodiments, the solid binary copper silicide material includes at least some Cu4Si. In some embodiments, the solid binary copper silicide material includes at least some Cu7Si. In some embodiments, the solid binary copper silicide material includes at least some CU0. S10.1. In some embodiments, the solid binary copper silicide material includes a combination of two or more of Cu5Si, Cu3Si, CU15S14, Cu4Si, Cu7Si, CU0.9S10.1 and a copper-silicon solid solution.
[0016] In another approach, the solid binary copper-silicon material may be in particulate form and can be used as is. The size distribution of the particulate, and hence the specific surface area (i.e., surface area per unit mass of solid binary copper-silicon material) may play a role in the relative efficiency of the solid binary copper- silicon material catalysts.
[0017] In one embodiment, the solid binary copper-silicon material may be deposited on the surface of a monolith and/or a honeycomb material (see, for instance, U.S. Patent No. 4,987,112). For example, particulate binary copper-silicon material may be introduced into an aqueous coating solution, thereby creating a slurry. Then, the monolith and/or honeycomb material may be coated with the slurry, thereby depositing the solid binary copper-silicon material on the surface of the monolith and/or honeycomb material, thereby creating a high- surface area material loaded with binary copper-silicon material. Other methods of producing high-surface area support materials loaded with binary copper-silicon material are described below.
[0018] As noted above, the catalytically converting comprises catalytically converting pollutants of an exhaust gas. As used herein, "pollutant" and the like means one or more substances of an exhaust gas that may be harmful to an environment and/or people. Examples of pollutants include CO (i.e. carbon monoxide), NOx, plain hydrocarbons, oxygenated hydrocarbons, and combinations thereof. In one embodiment, the exhaust gas includes from 0.01 to 20 vol. % of the CO. In one embodiment, the exhaust gas includes not greater than 10 vol. % of the CO. In another embodiment, the exhaust gas includes not greater than 5 vol. % of the CO. In yet another embodiment, the exhaust gas includes not greater than 1 vol. % of the CO. In another embodiment, the exhaust gas includes at least 0.05 vol. % of the CO. In yet another embodiment, the exhaust gas includes at least 0.1 vol. % of the CO.
[0019] As noted above, the pollutant may include NOx. As used herein, "NOx" means NO, N02, N20, N204, N205, and combinations thereof. In one embodiment, the exhaust gas includes from 1 to 100,000 ppmv (parts per million by volume) of the NOx. In another embodiment, the exhaust gas includes not greater than 50,000 ppmv of the NOx. In yet another embodiment, the exhaust gas includes not greater than 25,000 ppmv of the NOx. In another embodiment, the exhaust gas includes not greater than 10,000 ppmv of the NOx. In yet another embodiment, the exhaust gas includes not greater than 5,000 ppmv of the NOx. In another embodiment, the exhaust gas includes not greater than 2,000 ppmv of the NOx. In yet another embodiment, the exhaust gas includes at least 5 ppmv of the NOx. In another embodiment, the exhaust gas includes at least 10 ppmv of the NOx. In yet another embodiment, the exhaust gas includes at least 50 ppmv of the NOx. In another embodiment, the exhaust gas includes at least 100 ppmv of the NOx.
[0020] As noted above, the pollutant may include plain hydrocarbons and/or oxygenated hydrocarbons. As used herein, "plain hydrocarbon" and the like means a compound consisting only of carbon and hydrogen. In one embodiment, the plain hydrocarbons may comprise propane and/or larger plain hydrocarbons such as butane, octane and the like. In another embodiment, the plain hydrocarbons comprise ethane and/or methane. As used herein, "oxygenated hydrocarbon" and the like means a compound comprising carbon, hydrogen, and at least one oxygen atom. In one embodiment, the exhaust gas includes at least 1 ppmv of at least one of the plain hydrocarbons and the oxygenated hydrocarbons. In another embodiment, the exhaust gas includes at least 10 ppmv of at least one of the plain hydrocarbons and the oxygenated hydrocarbons. In yet another embodiment, the exhaust gas includes at least 50 ppmv of at least one of the plain hydrocarbons and the oxygenated hydrocarbons. In another embodiment, the exhaust gas includes at least 100 ppmv of at least one of the plain hydrocarbons and the oxygenated hydrocarbons.
[0021] In another approach, an emission control device uses the solid binary copper- silicon material (with or without a high-surface area support) to catalytically convert an exhaust gas. For example, and with reference now to FIG. 2, a combustion apparatus (100) (e.g., an exhaust gas source such as a mobile exhaust gas source or a stationary exhaust gas source) may produce an exhaust gas (150). The exhaust gas (150) then flows to an emission control device (200). The emission control device (200) comprises a housing. The housing has a waste gas inlet (210) for receiving the exhaust gas (150). The exhaust gas (150) includes a pollutant when it enters the waste gas inlet (210). The pollutant comprises a first amount of at least one of CO, NOx, plain hydrocarbons and oxygenated hydrocarbons. The housing includes a solid binary copper-silicon material (250) (with or without a high-surface area support) disposed therein and configured to communicate with the exhaust gas (150). The housing also has a treated gas outlet (230) for discharging the exhaust gas as a treated exhaust gas (170). Due to the solid binary copper-silicon material (250), the treated exhaust gas (170) may include a second (e.g., decreased) amount of at least one of the CO, the NOx, the plain hydrocarbons and the oxygenated hydrocarbons. As used herein, "emission(s) control device" and the like means a device having at least some solid binary copper-silicon material therein and configured to receive an exhaust gas having a pollutant. An emissions control device may be a stationary emissions control device or a mobile emissions control device. A stationary emissions control device is an emissions control device that receives an exhaust gas from a stationary source. Examples of stationary emissions control devices include emissions control devices that receive exhaust gas(es) from such stationary sources as coal-fired power plants, natural gas fired power plants, oil refineries, incinerators, wood stoves, and generators, among others. A mobile emissions control device is an emissions control device that receives an exhaust gas from a mobile source. Examples of mobile emissions control devices include emissions control devices that receive exhaust gas(es) from such mobile sources as gasoline powered automobiles, diesel powered automobiles, ships, airplanes, and lawnmowers, among others.
[0022] In one approach, an emissions control device of an automobile may be configured to realize a normal operating residence time of from about 25 ms to about 500 ms. In one embodiment, an emissions control device of an automobile may be configured to realize a residence time of from about 50 ms to about 300 ms. As used herein, "residence time" and the like means the time for an appropriate volume of an exhaust gas to flow through an amount of solid binary copper-silicon material. For example, for an exhaust gas stream flowing through a cylindrical tube packed with an amount of solid binary copper-silicon particles, the residence time equals the bulk volume of the amount of solid binary copper- silicon particles divided by the flow rate of the exhaust gas stream. As used herein, "bulk volume" of an amount of particles equals the volume of the particles plus the volume of the interparticle void spaces (i.e., spaces between the particles) plus the volume of the pores of the particles (if any).
II. Production of Binary Copper-Silicon Materials on High-Surface Area Supports
[0023] The present patent application also relates to methods of producing binary copper- silicon materials located on a high-surface area support material. Referring now to FIG. 3, one embodiment of a method for producing solid binary copper-silicon materials located on a high-surface area porous support material is illustrated. In the illustrated embodiment, the method comprises (a) forming copper metal particles on surfaces of a porous support material (100), and (b) converting the copper metal particles to solid binary copper-silicon materials (200). The converting step may include recovering (FIG. 7) a final product having the solid binary copper-silicon material located within the pores of the porous high-surface area material. The final product may be utilized in catalytic applications, such as in any of the catalytic applications described above.
[0024] As used herein, "copper metal particles" means particles consisting essentially of elemental copper (Cu). Copper metals particles are generally substantially free of oxygen and other materials that would prevent the copper reacting with silicon to form copper silicide. The copper metal particles generally have a bulk particle size (Do.os to D0.95) of from 3 nanometer (nm) to 100 microns (μιη). In one embodiment, the copper metal particles have a mean particle size (D0.5) of from 4 nanometers to 1 micron. In another embodiment, the copper metal particles have a mean particle size of from 5 nanometers to 500 nanometers. In yet another embodiment, the copper metal particles have a mean particle size of from 5 nanometers to 100 nanometers. In yet another embodiment, the copper metal particles have a mean particle size of from 5 nanometers to 50 nanometers.
[0025] As used herein, "porous high-surface area material" means a material having a plurality of pores, and an initial BET surface area of from 0.1 m 2 /gram to 2000 m 2 /gram. As used herein, "initial BET surface area" means a BET surface area of the material prior to forming the copper metal particles on surfaces of the porous high-surface area material. Examples of suitable porous high-surface area materials include aluminas (e.g., γ-Α1203), silicas, aluminosilicates, silicon carbides, silicon nitrides, activated carbon, zeolites, titania, zirconia, ceria, and mixtures thereof, and all of which may be doped or undoped. In one embodiment, the porous high-surface area material is an alumina. In another embodiment, the porous high-surface area material is a silica. In yet another embodiment, the porous high- surface area material is an aluminosilicate. In another embodiment, the porous high-surface area material is a silicon carbide. In yet another embodiment, the porous high-surface area material is a silicon nitride. In another embodiment, the porous high-surface area material is an activated carbon. In yet another embodiment, the porous high-surface area material is a zeolite. In another embodiment, the porous high-surface area material is a titania. In yet another embodiment, the porous high-surface area material is a zirconia. In another embodiment, the porous high-surface area material is a ceria. Known BET Surface Areas for these materials are provided below.
Figure imgf000014_0001
[0026] In one embodiment, the porous high-surface area material BET has an initial surface area of at least 1 m /gram. In another embodiment, the porous high-surface area material BET has an initial surface area of at least 5 m /gram. In yet another embodiment, the porous high-surface area material BET has an initial surface area of at least 10 m /gram. In another embodiment, the porous high-surface area material BET has an initial surface area of at least 20 m /gram.
[0027] The porous high-surface area material generally realizes an initial pore volume of from 0.05 to 2.5 cm /gram, as measured by the water evaporation method (i.e., pore volume = (weight of saturated sample - weight of dried sample)/density of water). As used herein, "initial pore volume" means a pore volume of the material prior to forming the copper metal particles on surfaces of the porous high-surface area material. In one embodiment, the porous high-surface area material realizes an initial pore volume of at least 0.1 cm /gram. In another embodiment, the porous high-surface area material realizes an initial pore volume of at least 0.25 cm /gram. In yet another embodiment, the porous high-surface area material realizes an initial pore volume of at least 0.5 cm /gram. In another embodiment, the porous high- surface area material realizes an initial pore volume of at least 0.75 cm /gram. In yet another embodiment, the porous high-surface area material realizes an initial pore volume of at least
1.0 cm /gram.
[0028] The porous high-surface area material may be in any suitable form, including powders, granules, beads (e.g., spheres), structured materials (e.g. monoliths, honeycomb, rods, needles, cylinders, etc.). For high temperature applications (e.g., where the final product is exposed to temperatures above about 300°C), high silicon aluminosilicates (e.g. 60-40 AI2O3-S1O2), silica, silicon carbide, and/or silicon nitride porous high-surface area materials may be preferred.
[0029] As noted above, the copper metal particles are located on the high-surface area support material. In this regard, the copper metal particles may be located on outer surfaces of the high-surface area support material and/or within pores of the high-surface area support material. When located within pores of the high-surface area support material, the copper metal particles may be partially located within the pores (e.g., a particle may partially located within a pore and partially located on an outer surface; a particle may be partially located within a pore and partially embedded within the high-surface area support material, among other scenarios) or fully located within the pores (e.g., fully within a pore without being embedded in the high- surface area support material). The same principles apply to copper oxide particles, described below, and to the binary copper-silicon materials produced from the copper metal particles or produced from the copper oxide particles.
[0030] Referring now to FIGS. 3-5, the copper metal particles may be formed (100) via any suitable method. In one embodiment, and referring now to FIG. 4, the forming step (100) may include precipitating the copper metal particles in a bath (400). In one embodiment, the precipitating step (400) comprises co-precipitating the copper metal particles and the porous high-surface area material in a bath. In other words, both the copper metal particles and the porous high-surface area support are precipitated (produced) in the same bath. For instance, copper nanoparticles can be prepared directly by addition of 1 mL of 0.01 M copper (II) acetate in ethanol to 5 mL water (all materials degassed of oxygen and held under inert nitrogen conditions). About 0.2-1.0 wt% polyvinylpyrrolidone (PVP) may be added as a capping agent to protect the Cu metal nanoparticles once formed. An excess of hydrazine monohydrate is then added to the mixture under refluxing conditions to form the copper nanoparticles. Tetraethylorthosilicate (TEOS) is added to the reaction mixture in an amount chosen to achieve the desired wt. % Cu on silica in the final product. The sol may be aged at 50 - 100°C. The pH of the solution can be adjusted as appropriate to further facilitate interaction of the sol gel with the copper nanoparticles. The slurry mixture can then be filtered and dried (e.g., at 100 - 150°C) while maintaining an inert atmosphere. The powder can then be heated (e.g., to 450-500°C) under reducing (e.g., H2) or inert (e.g., N2/Ar) conditions to drive off additional moisture and remove any capping agent, after which the reducing step (460), described below, may be accomplished.
[0031] In another embodiment, the precipitating step (400) comprises precipitating the copper metal particles in a bath comprising the porous high-surface area material. In this embodiment, the porous high-surface area material may be pre-existing in the bath, and the copper metal particles may be precipitated, such as via a change in pH of the bath. The precipitated copper metal particles are located on surfaces of the porous high-surface area material.
[0032] Sill referring to FIG. 4, in one embodiment, a method may include maintaining the precipitated copper metal particles in a non-oxidizing environment (420) until the conversion step (200). For instance, the copper metal particles may be maintained in a liquid or gaseous environment that prevents / restricts oxidation of the copper metal of the copper metal particles at least until initiation of the converting step (200). Exposing the copper metal particles to an oxidizing environment may result in the formation of a native oxide layer on the surface of the copper metal particles. The presence of oxygen, such as with a native oxide layer may, inhibit / prevent proper conversion of the copper metal particles to binary copper-silicon materials.
[0033] In other embodiments, and with reference still to FIG. 4, a method may include exposing the metal particles to an oxidizing environment (440). For instance, it may be difficult or impractical to maintain the copper metal particles in a non-oxidizing environment after precipitation. As one example, it may be efficient to dry the copper metal particles and corresponding porous high-surface area material in air for transportation or other purposes. In this embodiment, a method may comprise exposing the copper metal particles to a reducing environment (460) so as to, for example, remove any oxides from the copper metal particles (e.g., native oxide layers on surface of the copper metal particles). The exposing the copper metal particles to a reducing environment step (460) may include, for example, exposing the copper metal particles and corresponding porous high-surface area material to a reducing agent. A "reducing agent" means any material that reduces a copper precursor or a copper oxide to copper metal at elevated temperatures. In one embodiment, the reducing agent comprises one of ammonia and a hydrogen-containing gas (e.g., H2 gas). In one embodiment, the reducing agent consists essentially of hydrogen gas. The exposing step (460) may include maintaining an oxygen-free atmosphere. As used herein, an "oxygen-free atmosphere " means a gaseous environment that contains less than 1000 ppm, or less than 100 ppm, or less than 10 ppm oxygen (02).
[0034] In another embodiment relating to FIG. 4, copper oxide particles may also or alternatively be precipitated via the precipitating step (400). In these embodiments, after the precipitating step (400), the copper oxide particles may be subsequently reduced as per step (460), described above, and/or as per the reducing step (560) described relative to FIG. 5, below. For instance, the following preparation method for copper nanoparticles on a porous silica support can be used. Add a 4 M NaOH solution dropwise at a constant rate to a vigorously stirred 0.5 M Cu(N03)2 solution to produce copper oxide nanoparticles. Tetraethylorthosilicate (TEOS) can then be added in the proper proportion to achieve the desired wt. % of Cu vs. support and the resulting gel mixture aged at elevated temperatures (50-100°C). The pH of the slurry mixture can be varied as appropriate to facilitate interaction of the copper oxide nanoparticles with the silica sol. The slurry mixture can then be filtered and rinsed with DI water, dried at 100 - 150°C, calcined in air for 3-5 hours at 450°C, reduced in 1% hydrogen in argon at 500°C (1 hr), and finally reduced in 100% hydrogen at 500°C (1 hr).
[0035] Referring now to FIG. 5, the forming step (100) may also or alternatively include infiltrating pores of the porous high- surface area material with a copper precursor (500). As used herein, a "copper precursor" is a copper salt (e.g., copper nitrate) or copper organo- metallic compound (e.g., Cu(acac), i.e., copper acetyl acetonate) that is capable of forming copper metal particles upon appropriate subsequent reduction and/or oxidation of the copper precursor. In one embodiment, a copper precursor is dissolved in a copper precursor solution. As used herein, a "copper precursor solution" is a solution, aqueous or organic, comprising a copper precursor. The infiltrating step (500) may include one or more of wet impregnation (502), spray drying (504), and incipient wetness impregnation (506), as illustrated in FIG. 6.
[0036] Referring back to FIG. 5, in one approach, after the infiltrating step (500), the method may include the steps of reducing the copper precursor to copper metal particles (520). For instance, after the infiltration step, the copper precursor and corresponding porous high-surface area material may be dried (510), such as in an oxygen- free atmosphere. The copper precursor may then be reduced (520) via a reducing agent to form copper metal particles. In one embodiment, the reducing agent is a hydrogen-containing gas. In one embodiment, after the reducing step (520), the copper metal particles may be maintained in a reducing environment (530), after which the converting step (200) is completed.
[0037] In another embodiment, after the reducing step (520), the copper metal particles may be exposed to an oxidizing environment (560) (e.g., exposed to air for transportation purposes). After the exposing step (560), the copper metal particles may be exposed to a reducing environment (570), so as to, for example, remove any oxides from the copper metal particles (e.g., native oxide layers on surface of the copper metal particles). The exposing step (570) may include maintaining an oxygen-free atmosphere. The exposing the copper metal particles to a reducing environment step (570) may include, for example, exposing the copper metal particles and corresponding porous high-surface area material to a reducing agent. In one embodiment, the reducing agent comprises one of ammonia and a hydrogen- containing gas (e.g., H2 gas). In one embodiment, the reducing agent is a hydrogen- containing gas consisting of hydrogen gas (H2) and an inert gas. As used herein, an "inert gas" is one or more of a noble gas and nitrogen. In another embodiment, the reducing agent consists essentially of hydrogen gas (H2).
[0038] In some embodiments, it may be useful to utilize multiple reducing agents during the reducing step (570) (e.g., to control heat production and/or rates of reaction). In one embodiment, the reducing step (570) includes first exposing the copper particles and corresponding porous high-surface area material to a first reducing gas having a first concentration of a reducing agent, and then second exposing the copper particles and the corresponding porous high-surface area material to a second reducing gas having a second concentration of a reducing agent, wherein the second concentration is larger than the first concentration. In one embodiment, the first concentration of the first reducing gas is at least two times less than the second concentration. In another embodiment, the first concentration is at least five times less than the second concentration. In one embodiment, the first concentration is 0.1 to 2% H2 by volume, and the second concentration is larger than the first concentration, but not greater than 10% H2 by volume.
[0039] In a related embodiment, the reducing step may (570) include third exposing the copper particles and the corresponding porous high-surface area material to a third reducing gas having a third concentration of a reducing agent, wherein the third concentration is larger than the second concentration. In one embodiment, the third concentration is at least five times larger than the second concentration. In another embodiment, the third concentration is at least ten times larger than the second concentration. In yet another embodiment, the third concentration is at least twenty times larger than the second concentration. In another embodiment, the third reducing gas is consists essentially of the reducing agent (e.g., consists essentially of hydrogen gas (¾)).
[0040] In another approach, after the infiltrating step (500), the method may include oxidizing the copper precursor to copper oxide particles (540). For instance, after the infiltration step, the copper precursor and corresponding porous high-surface area material may be dried (510), such as in air. The copper precursor may then be oxidized (540) to form copper oxide particles. In one embodiment, the oxidizing step (540) comprises heating the copper precursor and the corresponding porous high-surface area material to a temperature sufficient to facilitate the oxidation of the copper precursor to copper oxide particles. In one embodiment, the copper precursor and the porous high-surface area material is heated to a temperature of at least 300°C but below a temperature where appreciable sintering of the copper oxide particles occurs. In one embodiment, the copper precursor and the porous high- surface area material is heated to a temperature of at least 350°C. In one embodiment, the copper precursor and the porous high-surface area material is heated to a temperature of at least 400°C. In one embodiment, the copper precursor and the porous high- surface area material is heated to a temperature of at least 450°C. In one embodiment, the copper precursor and the porous high-surface area material is heated to a temperature of at least 500°C. In any of these embodiments, the copper precursor and the porous high-surface area material may heated to a temperature of not greater than 800°C. In any of these embodiments, the copper precursor and the porous high-surface area material may heated to a temperature of not greater than 750°C. In any of these embodiments, the copper precursor and the porous high-surface area material may heated to a temperature of not greater than 700°C. In any of these embodiments, the copper precursor and the porous high-surface area material may heated to a temperature of not greater than 650°C. In any of these embodiments, the copper precursor and the porous high-surface area material may heated to a temperature of not greater than 600°C. In any of these embodiments, the copper precursor and the porous high-surface area material may heated to a temperature of not greater than 550°C.
[0041] After the oxidizing step (540), the method may include exposing the copper oxide particles to a reducing environment (570), as described above. The reducing step (570) may include exposing the copper oxide particles to a single reducing agent or multiple reducing agents, and optionally with varying concentrations, as described above.
[0042] Referring now to FIG. 7, the converting step (200) may include the steps of regulating the temperature to an appropriate silanation temperature (210), contacting the copper metal particles with silane materials (220), reacting the copper metal particles with the silane materials (230), and recovering a final product having binary copper- silicon materials within pores of the porous high-surface area material (240). The method may include maintaining (225) the appropriate silanation temperature during the contacting step (220) and the reacting step (230).
[0043] The regulating step (210) is optional and may be completed when the copper particles and corresponding porous high-surface area material are outside of the appropriate silanation temperature, described below. The regulating step (210) may be completed in any appropriate fashion, such as via contacting the copper particles with a fluid of appropriate temperature. In one embodiment, the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 100°C to 350°C. In another embodiment, the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 125°C to 350°C. In yet another embodiment, the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 150°C to 350°C. In another embodiment, the regulating step comprises bringing the copper particles and corresponding porous high- surface area material to a temperature of from 150°C to 325°C. In yet another embodiment, the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 150°C to 300°C. In another embodiment, the regulating step comprises bringing the copper particles and corresponding porous high- surface area material to a temperature of from 150°C to 275°C. In yet another embodiment, the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 150°C to 250°C. In another embodiment, the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 175°C to 250°C. In yet another embodiment, the regulating step comprises bringing the copper particles and corresponding porous high-surface area material to a temperature of from 175°C to 225°C. In one embodiment, the regulating step (210) comprises flowing a hydrogen- containing gas through a chamber comprising the copper particles and corresponding porous high-surface area material, wherein the hydrogen-containing gas has a temperature of from 100°C to 350°C, such as any of the above-described regulating temperature ranges. In one embodiment, the hydrogen-containing gas consists of hydrogen gas (H2).
[0044] After any necessary regulating step (210), the contacting step (220) is generally completed, and comprises contacting the copper particles and corresponding porous high- surface area material with a silane material. A "silane material" is a material having silicon and hydrogen, optionally with carbon, where the silicon of the silane material may react with the copper metal particles to form binary copper-silicon materials. Examples of some silane materials include monosilane (SiH4), disilane (Si2¾), tetramethyl-silane ((CH3)4Si), hexamethyldisilane ((CH3)6Si2), and chlorosilanes (e.g., HxSiCl(4_x), where x is from 0-3; methylchlorosilanes), among others. In one embodiment, the silane material is in the form of a silane-containing gas. In one embodiment, the silane-containing gas comprises monosilane gas (SiH4). In one embodiment, the silane-containing gas comprises a mixture of monosilane gas and hydrogen (H2) gas. In one embodiment, the silane-containing gas consists essentially of a mixture of monosilane gas and hydrogen gas.
[0045] In one embodiment, the silane-containing gas is a dilute silane-containing gas, and contains a dilute amount of silane materials. A dilute silane-containing gas is a gas having a sufficient amount of silane material to facilitate reaction of the silicon with the copper metal particles, but also having not so much silane material such that excessive silicon would form on the outer surface and/or within the pores of a porous support material. In one embodiment, a dilute silane-containing gas includes from 0.10 vol. % to 10 vol. % of a silane material (e.g., monosilane). In another embodiment, a dilute silane-containing gas includes from 0.25 vol. % to 8 vol. % of a silane material. In yet another embodiment, a dilute silane- containing gas includes from 0.50 vol. % to 6 vol. % of a silane material. In another embodiment, a dilute silane-containing gas includes from 0.50 vol. % to 5 vol. % of a silane material. In yet another embodiment, a dilute silane-containing gas includes from 0.50 vol. % to 4 vol. % of a silane material. In another embodiment, a dilute silane-containing gas includes from 0.5 vol. % to 3 vol. % of a silane material. In yet another embodiment, a dilute silane-containing gas includes from 0.75 vol. % to 3 vol. % of a silane material. In another embodiment, a dilute silane-containing gas includes from 0.75 vol. % to 2.5 vol. % of a silane material. In yet another embodiment, a dilute silane-containing gas includes from 0.75 vol. % to 2.0 vol. % of a silane material. In another embodiment, a dilute silane-containing gas includes from 1.0 vol. % to 2.0 vol. % of a silane material.
[0046] The reacting step (230) generally occurs concomitant to the contacting step (220), and includes reacting at least some of the copper metal with at least some of the silicon of the silane -material, thereby forming binary copper-silicon material. The produced binary-copper silicon materials may be any of the binary copper-silicon materials described above.
[0047] The contacting step (220) and reacting step (230) may involve short residence time and/or dilute silane-containing materials to produce copper-rich copper silicides (e.g., Cu5Si) and/or copper-silicon solid solutions. The contacting step (220) and reacting step (230) may involve longer residence times to produce silicon-rich copper silicides (e.g., Cu3Si).
[0048] The method may optionally include maintaining (225) the porous high-surface area material at a temperature of from 100°C to 350°C during the contacting (220) and reacting (230) steps (e.g., to control the reaction conditions and facilitate production of binary copper-silicon materials with limited by-products, such as excess silicon on the outer surfaces and/or within the pores of the porous high-surface area support). In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 100°C to 325°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 100°C to 300°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 100°C to 275°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 100°C to 250°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 100°C to 225°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 125°C to 250°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 150°C to 250°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 175°C to 250°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 175°C to 250°C during the contacting (220) and reacting (230) steps. In one embodiment, the method comprises maintaining the porous high-surface area material at a temperature of from 190°C to 210°C during the contacting (220) and reacting (230) steps.
[0049] The recovering step (240) generally comprises recovering a final product having binary copper-silicon material within the pores of the porous high-surface area material. The final product generally includes from 0.01 to 80 wt. % Cu, and the final product generally realizes a final BET surface area that is from 1% to 99% of the initial BET surface area. In one embodiment, the final product comprises from 0.01 to 60 wt. % Cu. In another embodiment, the final product comprises from 0.01 to 40 wt. % Cu. In yet another embodiment, the final product comprises from 0.01 to 30 wt. % Cu. In another embodiment, the final product comprises from 0.01 to 20 wt. % Cu. In yet another embodiment, the final product comprises from 0.01 to 10 wt. % Cu. In any of these embodiments, the final product may comprise at least 0.05 wt. % Cu. In any of these embodiments, the final product may comprise at least 0.25 wt. % Cu. In any of these embodiments, the final product may comprise at least 0.50 wt. % Cu. In any of these embodiments, the final product may comprise at least 0.75 wt. % Cu. In any of these embodiments, the final product may comprise at least 1.0 wt. % Cu.
[0050] As noted, the final product generally comprises a final BET surface area that is from 1% to 99% of the initial BET surface area. In one embodiment, the final product comprises a final BET surface area that is at least 5% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 10% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 15% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 20% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 25% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 30% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 35% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 40% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 45% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 50% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 55% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 60% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 65% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 70% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 75% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 80% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 85% of the initial BET surface area. In another embodiment, the final product comprises a final BET surface area that is at least 90% of the initial BET surface area. In yet another embodiment, the final product comprises a final BET surface area that is at least 95% of the initial BET surface area.
BRIEF DESCRIPTION OF THE DRAWINGS
[001] FIG. 1 is a schematic illustration of one embodiment of a method for catalytically converting pollutants of an exhaust gas using a solid binary copper-silicon material.
[002] FIG. 2 is a schematic illustration of one embodiment of a system for catalytically converting pollutants of an exhaust gas using a solid binary copper-silicon material.
[003] FIG. 3 is a flow chart illustrating one embodiment of a method for producing solid binary copper- silicon materials located on surfaces of porous high-surface area materials.
[004] FIG. 4 is a flow chart illustrating one embodiment of a method forming copper metal particles in pores of porous high-surface area materials.
[005] FIG. 5 is a flow chart illustrating another embodiment of a method forming copper metal particles in pores of porous high-surface area materials.
[006] FIG. 6 is a diagram illustrating various methods of infiltrating pores of porous high-surface area materials with copper precursor.
[007] FIG. 7 is a flow chart illustrating one embodiment of a method of concerting copper metal particles to binary copper-silicon materials located within pores of porous high- surface area materials.
DETAILED DESCRIPTION
[008] Example 1 - Testing Of Conventional Pt Catalyst
[009] 0.16 g of as purchased 1 wt.% Pt on 3.2 mm alumina pellets (Sigma Aldrich, batch number MKBG9524) were loaded into a ¼" o.d. quartz glass tube insert that was then slid into the steel tube of a flow reactor for testing. The reactor was then purged with N2 and heated to 500°C under 10 seem (standard cubic centimeters per minute) flow of N2 using a Lindberg/Blue 1" tube furnace. All gas flows to the reactor were controlled using Brooks mass flow controllers. After heating, the catalyst was allowed to cool to room temperature under the same N2 flow. After cooling, the catalyst was exposed to various gas flow rates at various temperatures, as shown in Table 1. The gases used were 02 (Airgas) and a gas mix (hereafter referred to as EPA mix) comprising 12.26 vol.%> C02, 0.7653 vol.%> CO, 397.4 ppmv (parts per million by volume) NO, 360.7 ppmv propane, and the balance N2 (Airgas). Reaction conversions were measured for CO oxidation (CO + 02 C02) and NO reduction (NO + CO -> N2 + C02 and/or 2NO -> N2 + 02) via GC-TCD (Gas Chromatography Thermal Conductivity Detection). To do this, a 20 of sample of the reactor effluent gas was injected via 6-way valve into an Agilent 7890 Gas Chromatograph (GC) having a thermal conductivity detector (TCD). Separation of gasses in the GC was achieved via injection onto a ShinCarbon ST packed column (Restek, 4 m long, 2 mm i.d., 80-100 mesh carbon particle size). The temperature program for the column to achieve separation of 02, N2, NO and CO was: 70°C (3 minute hold) ramp to 200°C (ramped over 4 minutes) for a total runtime of 7 minutes. To measure conversion of CO and NO, the TCD peak area (Peak Area) of the CO peak and the NO peak were compared to their respective peak areas at room temperature (where no conversion occurs) (Ref. Peak Area). Given that the TCD detector has a linear response to each component in these concentration ranges, the conversion for each component can be calculated from (1- Peak Area/Ref. Peak Area) xl00%. At each new temperature the catalyst was allowed to reach steady state for at least 1 hour before data was collected. When changing gas flow rates at a given temperature, the catalyst was allowed to reach steady state for at least 10 minutes between measurements.
Table 1 - Details of Example 1 - NO And CO Conversion Using Pt Catalyst
Figure imgf000025_0001
[0010] Example 2 - Testing Of Solid Binary Copper Silicide Catalyst
[0011] Cu5Si chunks (Alfa Aesar) were purchased and subsequently ball milled into a powder in a tungsten carbide vial with tungsten carbide balls in a 10: 1 weight ratio of balls to Cu5Si. The duration of milling was 1 hour. 0.89 g of the Cu5Si powder was loaded into a ¼" o.d. quartz glass tube insert with a quartz glass wool plug (to retain the powder in the reactor, Chemglass) and loaded into the reactor as described in Example 1. The Cu5Si powder was
2 2
expected to have a specific surface area of 0.11 m /g ± 0.02 m /g. The reactor was configured to realize a gas residence time of 300 ms ± 60 ms. Before measurement, the catalyst was first conditioned at 500°C under a combination of 1 seem 02 flow and 10 seem EPA mix flow, and allowed to cool under N2 flow to room temperature. The measurements taken at various gas flows and temperatures are shown in Table 2 and were carried out using the procedures described in Example 1.
Table 2 - Details of Example 2 - NO And CO Conversion Using CusSi Catalyst
Figure imgf000026_0001
[0012] Example 3 - Testing Of Conventional Pd Catalyst [0013] 0.43 g of as purchased 0.5 wt.% Pd on 3.2 mm alumina pellets (Alfa Aesar, batch number of B16Y031) were loaded into a ¼" o.d. quartz glass tube insert that was then slid into the steel tube of a flow reactor for testing. The reactor was then purged with N2 and heated to 500°C under a combined flow of 1 seem (standard cubic centimeters per minute) 02 (Airgas) and 10 seem EPA mix gas using a Lindberg/Blue 1" tube furnace. The EPA mix gas consisted of 12.26 vol.% C02, 0.7653 vol.% CO, 397.4 ppmv (parts per million by volume) NO, 360.7 ppmv propane, and the balance N2 (Airgas). All gas flows to the reactor were controlled using Brooks mass flow controllers. After heating, the catalyst was allowed to cool to room temperature under 10 seem of N2 flow. After cooling, the catalyst was exposed to 10 seem of EPA gas mix and 1 seem of 02 at various temperatures, as shown in Table 1. Reaction conversions were measured for propane oxidation (C3¾ + 5 02 3 C02 + 4 H20) via GC-TCD (Gas Chromatography Thermal Conductivity Detection). To do this, a 20 of sample of the reactor effluent gas was injected via 6-way valve into an Agilent 7890 Gas Chromatograph (GC) having a thermal conductivity detector (TCD). Separation of gasses in the GC was achieved via injection onto a ShinCarbon ST packed column (Restek, 4 m long, 2 mm i.d., 80-100 mesh carbon particle size). The temperature program for the column to achieve separation of 02, N2, NO, CO, C02 and C3¾ was: 70°C (2.15 minute hold) ramp to 280°C (ramped over 1.75 minutes), hold at 280°C for a 18.6 minutes for total runtime of 22.5 minutes. To measure conversion of propane, the TCD peak area (Peak Area) of the propane peak was compared to the propane peak area at room temperature (where no conversion occurs) (Ref. Peak Area). Given that the TCD detector has a linear response to propane over the range of concentrations tested, the conversion for each component can be calculated from (1- Peak Area/Ref. Peak Area) xl00%. At each new temperature the catalyst was allowed to reach steady state for at least 30 minutes before data was collected.
Table 3 - Details Of Example 3 - Propane Conversion Using Pd Catalyst
Figure imgf000027_0001
[0014] Example 4 - Testing Of Solid Binary Copper Silicide Catalyst
[0015] Cu5Si chunks (Alfa Aesar) were purchased and subsequently ball milled into a powder in a tungsten carbide vial with tungsten carbide balls in a 10: 1 weight ratio of balls to Cu5Si. The duration of milling was 1 hour. 1.11 g of the Cu5Si powder was loaded into a ¼" o.d. quartz glass tube insert with a quartz glass wool plug (to retain the powder in the reactor, Chemglass) and loaded into the reactor as described in Example 1. The Cu5Si powder was
2 2
expected to have a specific surface area of 0.11 m /g ± 0.02 m /g. The reactor was configured to realize a gas residence time of 300 ms ± 60 ms. Before measurement, the catalyst was first conditioned at 500°C under a combination of 1 seem 02 flow and 10 seem EPA mix flow, and allowed to cool under N2 flow to room temperature as described in Example 1. The measurements taken at various temperatures are shown in Table 4 and were carried out using the procedures described in Example 1.
Table 4 - Details of Example 4 - Propane Conversion Using CusSi Catalyst
Figure imgf000028_0001
[0016] Example 5 - Preparation And Testing Of Essentially Phase-Pure Cu iSi Solid Binary Copper Silicide Catalyst
[0017] Cu powder (99%, <75 μιη; Sigma- Aldrich) and Si powder (at least 99.999%; Hemlock Semiconductor) were purchased. An agate mortar and pestle was used to grind 3.5184 g (55.364 mmole) of the Cu powder together with 0.5072 g (18.06 mmole) of the Si powder thereby forming a Cu/Si powder mixture. This mixture was then loaded into a graph- foil lined graphite punch and die set (40mm x 20mm graphite die with 20mm x 30mm graphite punches). The punch and die set was then loaded into the Spark Plasma Sintering (SPS) chamber of a Pulsed Electric Current Sintering system (Thermal Technology, LLC, Model 10-4). The SPS chamber was evacuated to a pressure < 2E-3 torr. Next, a uniaxial pressure of 1 MPa was applied to the mixture via the SPS chamber. The mixture in the SPS chamber was then heated at 200 °C»min-l to 300 °C and held for five minutes. The temperature of the SPS die was monitored using a thermocouple positioned directly under the sample. The pressure in the SPS chamber was then increased to 60 MPa at 20MPa»min-l . The temperature in the SPS chamber was then increased to 700 °C at 200 °C»min-l and held for 2h. The contents of the SPS chamber were then cooled as quickly as possible to room temperature. Thus, an essentially phase-pure Cu3Si solid binary copper silicide catalyst material was formed. The Cu3Si solid binary copper silicide catalyst material was prepared for catalysis via ball milling for 4h using three WC spheres, thereby forming an essentially phase-pure Cu3Si solid binary copper silicide catalyst powder. Powder X-ray diffraction (XRD) results show the Cu3Si powder comprises essentially phase-pure Cu3Si. The powder X-ray diffraction patterns were collected in Bragg-Brentano geometry from 10 to 80° 2Θ in 0.02° increments at 0.4 second per step with a Cu anode operating at 40 kV and 44 mA. An open height limiting slit, 0.6 mm divergence slit, 22.92 mm scattering slit, 37.77 mm receiving slit were used, and intensity data were collected with a high speed detector.
[0018] 0.99 g of essentially phase-pure Cu3Si solid binary copper silicide catalyst powder (prepared as described above) was loaded into a ¼" o.d. quartz glass tube insert which was then slid into the steel tube of a flow reactor for testing. The reactor was then purged with 1 seem C"2 and 10 seem EPA mix. All gas flows to the reactor were controlled using Brooks mass flow controllers. The catalyst was heated under this gas flow to 500°C for 1 hour using a Lindberg/Blue 1" tube furnace. The catalyst was then cooled to room temperature under 10 seem flow of N2. After cooling, the catalyst was exposed to various gas flow rates at various temperatures. The measurements taken at various gas flows and temperatures are shown in Table 5 and were carried out using the procedures described in Example 1.
- Details of Example 5 - NO And CO Conversion Using Essentially Phase-Pure
CU3S1 Catalyst
Figure imgf000029_0001
EPA Mix Flow NO CO
Temperature 02 Flow Rate
Rate Conversion Conversion (°C) (seem)
(seem) (%) (%)
80 10 1 6.7 0.9
90 10 1 16.7 1.2
100 10 1 10.0 1.4
110 10 1 10.0 2.0
120 10 1 10.0 2.7
130 10 1 10.0 5.2
140 10 1 13.3 17.2
150 10 1 10.0 27.1
160 10 1 10.0 46.7
170 10 1 6.7 78.5
180 10 1 6.7 95.8
[0019] Example 6 - Preparation And Testing Of Essentially Phase-Pure CugSi Solid Binary Copper Silicide Catalyst
[0020] Cu wire (99.999%, 2.0mm diameter; Sigma-Aldrich) and Si pieces (at leatst 99.99%, -lOmm pieces; Hemlock Semiconductor) were purchased. A cooled copper crucible was then loaded with 4.57 g (71.9 mmole) of the Cu wire and 0.40 g (72 mmole) of the Si pieces. The loaded copper crucible was placed into the chamber of an arc melter (MRF model SA200). The chamber was then purged with Argon gas. The Cu wire and Si pieces in the copper crucible were then melted together for -60s using an arc generated from a ceriated-tungsten electrode. The catalyst was then re-melted an additional three times using the same procedure, thereby forming an essentially phase-pure Cu5Si solid binary copper silicide catalyst material. The Cu5Si solid binary copper silicide catalyst material was prepared for catalysis via ball milling for 4h using three WC spheres, thereby forming an essentially phase-pure Cu5Si solid binary copper silicide catalyst powder. Powder X-ray diffraction (XRD) results show the Cu5Si powder comprises essentially phase-pure Cu5Si. The powder X-ray diffraction patterns were collected using the procedures described in Example 5.
[0021] 1.01 g of essentially phase-pure Cu5Si solid binary copper silicide catalyst powder (prepared as described above) was then loaded into a ¼" o.d. quartz glass tube insert which was then slid into the steel tube of a flow reactor for testing. The reactor was then purged with 1 seem 02 and 10 seem EPA mix. All gas flows to the reactor were controlled using Brooks mass flow controllers. The catalyst was heated under this gas flow to 500°C for 1 hour using a Lindberg/Blue 1" tube furnace. The catalyst was then cooled to room temperature under 10 seem flow of N2. After cooling, the catalyst was exposed to various gas flow rates at various temperatures. The measurements taken at various gas flows and temperatures are shown in Table 6 and were carried out using the procedures described in Example 1.
Table 6 - Details of Example 6 - NO And CO Conversion Using Essentially Phase-Pure
CusSi Catalyst
Figure imgf000031_0001
[0022] Example 7 - Preparation And Testing Of Essentially Phase-Pure Cu-Si Solid Solution Catalyst
[0023] Cu powder (99%, <75 μιη; Sigma-Aldrich) and Si powder (at least 99.999%; Hemlock Semiconductor) were purchased. A WC-lined steel milling vial was charged with three WC spheres, 4.8384 g (76.135 mmole) of the Cu powder, and 0.1662 g (5.917 mmole) of the Si powder. The Cu and Si powders were milled together for 60min thereby forming a Cu/Si powder mixture. This mixture was then Spark Plasma Sintered in a graph-foil lined graphite punch and die set using the procedures described in Example 5, thereby forming an essentially phase-pure Cu-Si solid solution catalyst material. The Cu-Si solid solution catalyst material was prepared for catalysis by ball milling for lh using three WC spheres, thereby forming a Cu-Si solid solution catalyst powder. Powder XRD results show a slight shift in 2Θ that is indicative of Si substitution into the Cu lattice. The powder X-ray diffraction patterns were collected using the procedures described in Example 5.
[0024] 1.13 g of essentially phase-pure Cu-Si solid solution catalyst powder (prepared as described above) was then loaded into a ¼" o.d. quartz glass tube insert which was then slid into the steel tube of a flow reactor for testing. The reactor was then purged with 1 seem 02 and 10 seem EPA mix. All gas flows to the reactor were controlled using Brooks mass flow controllers. The catalyst was heated under this gas flow to 500°C for 1 hour using a Lindberg/Blue 1" tube furnace. The catalyst was then cooled to room temperature under 10 seem flow of N2. After cooling, the catalyst was exposed to various gas flow rates at various temperatures. The measurements taken at various gas flows and temperatures are shown in Table 7 and were carried out using the procedures described in Example 1.
Table 7 - Details of Example 7 - NO And CO Conversion Using Essentially Phase-Pure
Cu-Si Solid Solution Catalyst
Figure imgf000032_0001
EPA Mix Flow NO CO
Temperature 02 Flow Rate
Rate Conversion Conversion (°C) (seem)
(seem) (%) (%)
180 10 1 12.1 73.8
190 10 1 15.2 87.0
200 10 1 9.1 95.5
210 10 1 15.2 98.5
[0025] Example 8 - Preparation of Binary Copper-Silicon Materials on High- Surface Area Porous Support Materials
[0026] Materials and Methods. The various supports used were as follows: γ-Α1203 (Sasol, Catalox 47-7, Lot# 1403-76-10, BET surface area = 175 m2/g, pore volume = 0.47 cm /g, pore size = 11 nm); La-Al203 (2.41 wt% La, Sasol, Lot# C-3185, BET surface area = 213 m2/g, pore volume = 0.80 cm3/g); SIRALOX 40 (40 wt% SiO2/60 wt% A1203, Sasol, Lot# B33369, BET surface area = 500 m2/g, pore volume = 0.90 cm3/g); SIRALOX 10 (10 wt% SiO2/90 wt% A1203, Sasol, Lot# B27197, BET surface area = 400 m2/g, pore volume = 0.75 cm3/g); Si02 (>99%, Sigma Aldrich, Davisil, Lot# MKBL7107V, BET surface area = 480 m2/g, pore volume 0.75 cm3/g); SiC (SiCAT, Lot# SD0076B2, BET surface area = 30.9 m2/g; pore volume 0.52 cm3/g); Si3N4 (98.5%, Sigma Aldrich, Lot# MKBR4359V, BET
2 3
surface area 103-123 m /g, pore volume 2.13 cm /g); Cu5Si (Alfa Aesar). Copper(II) nitrate hemi(pentahydrate) (98%>) was purchased from Sigma-Aldrich. Gases (UHP grade) were purchased from Airgas.
[0027] Physical and Analytical Measurements. The powder X-ray diffraction patterns were collected in Bragg-Brentano geometry from 10 to 80° 2Θ in 0.02° increments at 0.4 second per step with a Cu anode operating at 40 kV and 44 mA. An open height limiting slit, 0.6 mm divergence slit, 22.92 mm scattering slit, 37.77 mm receiving slit were used, and intensity data were collected with a high speed detector. Brunauer-Emmett-Teller (BET) surface area and pore characteristics were determined using a Micromeritics ASAP 2020 surface area analyzer with a working range from 0.5-3000 m /g. Transmission Electron Microscope (TEM) images were acquired using a 200kV JEM 21 OOF microscope. The EDS were collected using a Bruker system. TEM samples were prepared by crushing samples into smaller particles using glass slides and were collected onto a carbon support film of a Cu grid. The Energy Dispersive Spectroscopy (EDS) spectra were collected with acquisition time of 10 s in combination with Scanning Transmission Electron Microscopy (STEM). The elemental maps were collected for about 36 minutes. Silicidation reactor effluents were monitored using a Stanford Research Systems Residual Gas Analyzer. [0028] Example 8a-l
[0029] Cu3Si impregnated γ-Α1203 (Cu3Si/y-Al203) samples were prepared via 1) H2 reduction and 2) SiH4 silicidation of CuO impregnated γ-Α1203 (CuO/y-Al203). CuO/y-Al203 samples were prepared using conventional wet impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of γ-Α1203 were dried in air at 550 °C for 4 h. An amount of 49.99 g of dried γ-Α1203 beads were immersed in 75 mL of a 3.71 M aqueous solution of Cu(N03)2 2.5H20. The mixture was then placed in a vacuum chamber (75 torr) for 15 min to accelerate the impregnation. The impregnated γ-Α1203 beads were isolated via vacuum filtration, and were dried overnight at 120 °C in a vacuum oven (75 torr). After drying, the impregnated γ-Α1203 beads were placed into alumina boats and were calcined in a muffle furnace in air at 450 °C for 5 h. After calcination, 57.72 g CuO/y-Al203 was isolated. Cu loading was determined gravimetrically to be 15.5 wt% CuO, and 10.7 wt% Cu. Powder XPvD analysis shows the crystalline composition of this material consists of CuO and (A1203)5.333.
[0030] Cu3Si/Y-Al203 samples were prepared by loading 3.9990 g CUO/Y-A1203 (10.7 wt% Cu) into a ½" o.d. stainless steel flow reactor. The reactor was then evacuated with a roughing pump to a pressure < 50 mtorr. The reactor was then filled with Ar and heated to 500 °C (10 °C/min ramp) under 100 standard cubic centimeters per minute (seem) Ar gas flow using a Lindberg/Blue 1" tube furnace. All gas flows were controlled using MKS mass flow controllers. The reactor effluent was monitored using an RGA. Once the reactor reached 500 °C, the CuO/y-Al203 was reduced in 1% H2 in Ar (5 seem H2, 500 seem Ar) for 55 min, then 5% H2 in Ar (5 seem H2, 95 seem Ar) for 15 min, then 50 seem H2 for 10 min. After reduction, the reactor was cooled under 50 seem H2 flow to 200 °C. After cooling to 200 °C, the H2 was turned off and 100 seem 1% SiH4 in H2 was flowed for 20.25 h. After the desired silicidation time, 1% SiH4 in H2 was turned off, and the reactor was cooled to room temperature under 50 seem H2. An amount of 4.0391 g product was isolated. Powder XRD analysis shows the crystalline composition of this material consists of Cu3Si and (Al203)5.3333.
[0031] Example 8a-2
[0032] 0.34 g of as prepared Cu3Si on A1203 was loaded into a ¼" o.d. quartz glass tube insert that was then slid into the steel tube of a flow reactor for testing. The reactor was then purged with N2 and heated to 500°C under 10 seem (standard cubic centimeters per minute) flow of N2 using a Lindberg/Blue 1 " tube furnace. All gas flows to the reactor were controlled using Brooks mass flow controllers. After heating, the catalyst was allowed to cool to room temperature under the same N2 flow. After cooling, the catalyst was exposed to various gas flow rates at various temperatures, as shown in Table 1. The gases used were 02 (Airgas) and a gas mix (hereafter referred to as EPA mix) comprising 12.26 vol.% C02, 0.7653 vol.% CO, 397.4 ppmv (parts per million by volume) NO, 360.7 ppmv propane, and the balance N2 (Airgas). Reaction conversions were measured for CO oxidation (CO + 02 C02) and NO reduction (NO + CO -> N2 + C02 and/or 2NO -> N2 + 02) via GC-TCD (Gas Chromatography Thermal Conductivity Detection). To do this, a 20 of sample of the reactor effluent gas was injected via 6-way valve into an Agilent 7890 Gas Chromatograph (GC) having a thermal conductivity detector (TCD). Separation of gasses in the GC was achieved via injection onto a ShinCarbon ST packed column (Restek, 4 m long, 2 mm i.d., 80-100 mesh carbon particle size). The temperature program for the column to achieve separation of 02, N2, NO and CO was: 70°C (3 minute hold) ramp to 200°C (ramped over 4 minutes) for a total runtime of 7 minutes. To measure conversion of CO and NO, the TCD peak area (Peak Area) of the CO peak and the NO peak were compared to their respective peak areas when flowing through a bypass line that did not pass the gas mixture over the catalyst, but instead passed it through a blank glass tube at room temperature (where no conversion occurs) (Ref. Peak Area). Given that the TCD detector has a linear response to each component in these concentration ranges, the conversion for each component can be calculated from (1- Peak Area/Ref. Peak Area) xl00%. At each new temperature the catalyst was allowed to reach steady state for at least 30 minutes before data was collected. When changing gas flow rates at a given temperature, the catalyst was allowed to reach steady state for at least 10 minutes between measurements. The results of this test are shown in Table 8.
Table 8. NO and CO conversion using CusSi/Al2Os catalyst
Figure imgf000035_0001
*This first entry is a blank run through a bypass line that flows through an empty glass tube and not over the catalyst. This is done to get a reference peak area at 0% conversion for both CO and NO.
[0033] After several days of flowing EPA gas over the CU3S1/AI2O3 catalyst, the CU3S1/AI2O3 catalyst shows a lower conversion of NO and CO (i.e., the catalyst deactivates and requires a higher temperature to achieve a given conversion). The 100% NO conversion temperature reaches a steady state level after 3 - 4 days and is achieved at 150 - 180 °C. The 100% CO conversion temperature reaches a steady state level after 3 - 4 days and is achieved at 120 - 150 °C. The catalyst can be regenerated to full activity by raising the catalyst temperature for a brief period (1 hour) to 500 °C. After cooling to the reaction temperature, the catalyst demonstrates the same level of conversion as fresh catalyst shown in Table 8.
[0034] Example 8a-3
[0035] Reaction conversions for the as prepared CU3S1 on AI2O3 catalyst were measured for propane oxidation (C3H8 + 5 O2 3 CO2 + 4 ¾0) via GC-TCD (Gas Chromatography Thermal Conductivity Detection). To do this, a 20 of sample of the reactor effluent gas was injected via 6-way valve into an Agilent 7890 Gas Chromatograph (GC) having a thermal conductivity detector (TCD). Separation of gasses in the GC was achieved via injection onto a ShinCarbon ST packed column (Restek, 4 m long, 2 mm i.d., 80-100 mesh carbon particle size). The temperature program for the column to achieve separation of 02, N2, NO, CO, C02 and C3¾ was: 70°C (2.15 minute hold) ramp to 280°C (ramped over 1.75 minutes), hold at 280°C for a 18.6 minutes for total runtime of 22.5 minutes. To measure conversion of propane, the TCD peak area (Peak Area) of the propane peak was compared to the propane peak area at room temperature (where no conversion occurs) (Ref. Peak Area). Given that the TCD detector has a linear response to propane over the range of concentrations tested, the conversion for each component can be calculated from (1- Peak Area/Ref. Peak Area) xl00%. At each new temperature the catalyst was allowed to reach steady state for at least 30 minutes before data was collected. The results of this test are shown in Table 9.
Table 9. Propane conversion using CU3S1/AI2O3 catalyst
Figure imgf000036_0001
Propane Peak EPA Mix Flow 02 Flow Propane
Temperature Area Rate Rate Conversion
(°C) (%) (seem) (seem) (%)
170 0.131 10 1 10.3
180 0.124 10 1 15.1
190 0.125 10 1 14.4
200 0.12 10 1 17.8
210 0.116 10 1 20.5
220 0.115 10 1 21.2
230 0.114 10 1 21.9
240 0.109 10 1 25.3
250 0.09 10 1 38.4
260 0.086 10 1 41.1
270 0.066 10 1 54.8
280 0.046 10 1 68.5
290 0.035 10 1 76.0
300 0.02 10 1 86.3
The propane conversion is stable over time. The catalyst does not demonstrate any deactivation for this reaction.
[0036] Example 8a-4
[0037] A quartz glass sample tube that is sealed at one end was filled with a small amount (0.2917 g) of the as-prepared Cu3Si on A1203 catalyst sample. The tube was then evacuated on a Schlenk line to 50 miUitorr. The sample was then taken through a cycle of backfilling with argon, and evacuating to 50 miUitorr a total of 3 times. The glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon. The sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed. XRD analysis indicated the presence of crystalline Cu and A1203 and CuO (from oxidation of Cu after exposure to air on opening the vial), indicating that the Si had diffused out of the Cu3Si and into the A1203 support at high temperatures.
[0038] Example 8b-l
[0039] Cu3Si was impregnated into lanthana doped γ-Α1203 support (Cu3 Si/La- A1203) via H2 reduction and subsequent SiH4 silicidation of CuO impregnated La-Al203. The samples were prepared by conventional incipient wetness impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of support were dried in air at 550 °C for 4 h. 15.50 mL of a 2.16 M aqueous solution of Cu(N03)2'3H20 was added dropwise while stirring to 19.99 g of dried La-Al203 powder. The mixture was then placed in a vacuum oven (75 torr) and dried overnight at 120 °C. After drying, Cu loading was determined gravimetrically to be 9.6 wt% Cu. Next, 1.4982 g of sample was loaded into a ½" o.d. glass tube flow reactor and heated at 10 °C/min ramp under 50 seem air flow to 450 °C, where it was held and calcined for 5 hours. All gas flows were controlled with MKS mass flow controllers and the furnace used was a Lindberg/Blue 1" tube furnace. The reactor was then purged under argon flow at 495 seem and ramped at 10 °C/min to 500 °C. Then, a mixture of 5 seem H2 / 495 seem Ar was flowed over the sample to begin reduction. After 50 minutes, the mixture was changed to 5 seem H2 / 95 seem Ar. After an additional 15 minutes, the mixture was changed to 50 seem H2 and no argon flow. After 5 minutes, the reactor was allowed to cool to 200 °C under 50 seem flow of H2. Once at 200 °C, a mixture of 50 seem H2 and 50 seem of a 2% SiH4 in H2 was flowed over the sample for 20 hours. After reaction, the reactor was allowed to cool under 100 seem of argon flow. The sample was removed from the reactor and powder XRD analysis indicates the formation of Cu3Si.
[0040] Example 8b-2
[0041] 0.21 g of as prepared Cu3Si on La-Al203 was loaded into a ¼" o.d. quartz glass tube insert that was then slid into the steel tube of a flow reactor for testing. The reactor was then heated to 500°C under 10 seem flow of EPA gas using a Lindberg/Blue 1" tube furnace. All gas flows to the reactor were controlled using Brooks mass flow controllers. After heating, the catalyst was allowed to cool to room temperature under 10 seem N2 flow. After cooling, the catalyst was exposed to various gas flow rates at various temperatures, as shown in Tables 5 and 6. The gases used were 02 and EPA gas mix. Reaction conversions were measured for CO oxidation, NO reduction, and hydrocarbon oxidation by GC-TCD according to the procedures described in example 8a-2 and 8a-3. The results of this test are shown in Tables 10 and 11.
Table 10. NO reduction using CujSi/La-AhOi catalyst
Figure imgf000038_0001
*This first entry is a blank run through a bypass line that flows through an empty glass tube and not over the catalyst. This is done to get a reference peak area at 0% conversion for both CO and NO.
[0042] After several days of flowing EPA gas over the catalyst, the catalyst shows a lower conversion of NO and CO (i.e., the catalyst deactivates and requires a higher temperature to achieve a given conversion). The 100% NO conversion temperature reaches a steady state level after 5 - 6 days and is achieved at 170 - 190 C. The 100% CO conversion temperature reaches a steady state level after 6 - 7 days and is achieved at 140 - 170 C. The catalyst can be regenerated to full activity by raising the catalyst temperature for a brief period (1 hour) to 500°C. After cooling to the reaction temperature, the catalyst demonstrates the same level of conversion as fresh catalyst.
Table 11. Propane conversion using Cu3Si/La-Al203 catalyst
Figure imgf000039_0001
[0043] Example 8b-3
[0044] A quartz glass sample tube that is sealed at one end was filled with a small amount (0.1089 g) of the as-prepared Cu3Si on La-Al203 sample. The tube was then evacuated on a Schlenk line to 50 millitorr. The sample was then taken through a cycle of backfilling with argon, and evacuating to 50 millitorr a total of 3 times. The glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon. The sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed. XRD analysis indicated the presence of Cu and no copper silicides could be detected, indicating that the Si had diffused out of the Cu3Si and into the La-Al203 support.
[0045] Example 8c-l
[0046] Cu3Si was impregnated into SIRALOX 10 support (Cu3Si/S-10) via H2 reduction and subsequent SiH4 silicidation of CuO impregnated SIRALOX 10. The samples were prepared by conventional incipient wetness impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of support were dried in air at 550 °C for 4 h. 14.58 mL of a 2.31 M aqueous solution of Cu(N03)2 3H20 was added dropwise while stirring to 20.10 g of dried SIRALOX 10 powder. The mixture was then placed in a vacuum oven (75 torr) and dried overnight at 120 °C. After drying, Cu loading was determined gravimetrically to be 9.6 wt%> Cu. Next, 1.4978 g of sample was loaded into a ½" o.d. glass tube flow reactor and heated at 10 °C/min ramp under 50 seem air flow to 450 °C, where it was held and calcined for 5 hours. All gas flows were controlled with MKS mass flow controllers and the furnace used was a Lindberg/Blue 1" tube furnace. The reactor was then purged under argon flow at 495 seem and ramped at 10 °C/min to 500 °C. Then, a mixture of 5 seem H2 / 495 seem Ar was flowed over the sample to begin reduction. After 50 minutes, the mixture was changed to 5 seem H2 / 95 seem Ar. After an additional 15 minutes, the mixture was changed to 50 seem H2 and no argon flow. After 5 minutes, the reactor was allowed to cool to 200 °C under 50 seem flow of H2. Once at 200 °C, a mixture of 50 seem H2 and 50 seem of a 2% SiH4 in H2 was flowed over the sample for 20 hours. After reaction, the reactor was allowed to cool under 100 seem of argon flow. The sample was removed from the reactor and powder XRD analysis shows the material contains Cu3Si.
[0047] Example 8c-2
[0048] A quartz glass sample tube that is sealed at one end was filled with a small amount (0.2016 g) of the as-prepared Cu3Si on SIRALOX 10 support sample. The tube was then evacuated on a Schlenk line to 50 millitorr. The sample was then taken through a cycle of backfilling with argon, and evacuating to 50 millitorr a total of 3 times. The glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon. The sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed. XRD analysis indicated the presence of Cu and no copper silicides could be detected, indicating that the Si had diffused out of the Cu3Si and into the SIRALOX 10 support.
[0049] Example 8d-l
[0050] Cu3Si was impregnated into SIRALOX 40 support (Cu3Si/S-40) via H2 reduction and subsequent S1H4 silicidation of CuO impregnated SIRALOX 40. The samples were prepared by conventional wet impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of support were dried in air at 550 °C for 4 h. An amount of 20.035 g of dried SIRALOX 40 powder was immersed in 21.50 mL of a 1.92 M aqueous solution of Cu(N03)2-3H20. The mixture was then placed in a vacuum oven (75 torr) and dried overnight at 120 °C. After drying, Cu loading was determined gravimetrically to be 11.5 wt% Cu. Next, 1.5038 g of sample was loaded into a ½" o.d. glass tube flow reactor and heated at 10 °C/min ramp under 50 seem air flow to 450 °C, where it was held and calcined for 5 hours. All gas flows were controlled with MKS mass flow controllers and the furnace used was a Lindberg/Blue 1" tube furnace. The reactor was then purged under argon flow at 495 seem and ramped at 10 °C/min to 500 °C. Then, a mixture of 5 seem H2 / 495 seem Ar was flowed over the sample to begin reduction. After 50 minutes, the mixture was changed to 5 seem H2 / 95 seem Ar. After an additional 15 minutes, the mixture was changed to 50 seem H2 and no argon flow. After 5 minutes, the reactor was allowed to cool to 200 °C under 50 seem flow of H2. Once at 200 °C, a mixture of 50 seem H2 and 50 seem of a 2% SiH4 in H2 was flowed over the sample for 20 hours. After reaction, the reactor was allowed to cool under 100 seem of argon flow. The sample was removed from the reactor and powder XRD analysis shows the formation of Cu3Si.
[0051] Example 8d-2
[0052] 0.20 g of as prepared Cu3Si on SIRALOX 40 was loaded into a ¼" o.d. quartz glass tube insert that was then slid into the steel tube of a flow reactor for testing. The reactor was then heated to 500°C under 10 seem flow of EPA gas using a Lindberg/Blue 1" tube furnace. All gas flows to the reactor were controlled using Brooks mass flow controllers. After heating, the catalyst was allowed to cool to room temperature under 10 seem N2 flow. After cooling, the catalyst was exposed to various gas flow rates at various temperatures, as shown in Table 12. The gases used were 02 and EPA gas mix. Reaction conversions were measured for CO oxidation and NO reduction by GC-TCD according to the procedure described in example 8a-2. The results of this test are shown in Table 12.
Table 12. NO and CO conversion using CusSi/S-40 catalyst
Figure imgf000041_0001
[0053] Example 8d-3
[0054] A quartz glass sample tube that is sealed at one end was filled with a small amount (0.2054 g) of the as-prepared Cu3Si on SIRALOX 40 sample. The tube was then evacuated on a Schlenk line to 50 millitorr. The sample was then taken through a cycle of backfilling with argon, and evacuating to 50 millitorr a total of 3 times. The glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon. The sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed. XRD analysis indicated the presence of crystalline, Cu7Si and a small amount of CU0. S10.1, indicating that the Si remains associated with the copper on this support when exposed to high temperatures.
[0055] Example 8e-l
[0056] Cu3Si was impregnated into SiC support (Cu3Si/SiC) via H2 reduction and subsequent SiH4 silicidation of CuO impregnated SiC. The samples were prepared by conventional wet impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of support were dried in air at 550 °C for 4 h. An amount of 20.022 g of dried SiC powder was immersed in 40 mL of a 0.874 M aqueous solution of Cu(N03)2-3H20. The mixture was then placed in a vacuum chamber (75 torr) for 15 min to accelerate the impregnation. The impregnated support was isolated via vacuum filtration, and dried overnight at 120 °C in a vacuum oven (75 torr). After drying, Cu loading was determined gravimetrically to be 10.0 wt% Cu. Next, 3.997 g of sample was loaded into a ½" o.d. glass tube flow reactor and heated at 10 °C/min ramp under 50 seem air flow to 450 °C, where it was held and calcined for 5 hours. All gas flows were controlled with MKS mass flow controllers and the furnace used was a Lindberg/Blue 1" tube furnace. The reactor was then purged under argon flow at 495 seem and ramped at 10 °C/min to 500 °C. Then, a mixture of 5 seem H2 / 495 seem Ar was flowed over the sample to begin reduction. After 50 minutes, the mixture was changed to 5 seem H2 / 95 seem Ar. After an additional 15 minutes, the mixture was changed to 50 seem H2 and no argon flow. After 5 minutes, the reactor was allowed to cool to 200 °C under 50 seem flow of H2. Once at 200 °C, a mixture of 50 seem H2 and 50 seem of a 2% SiH4 in H2 was flowed over the sample for 20 hours. After reaction, the reactor was allowed to cool under 100 seem of argon flow. The sample was removed from the reactor and powder XRD analysis shows the crystalline composition of this material consists of Cu3Si and SiC.
[0057] Example 8e-2
[0058] 0.31 g of as prepared Cu3Si on SiC was loaded into a ¼" o.d. quartz glass tube insert that was then slid into the steel tube of a flow reactor for testing. The reactor was then heated to 500°C under 10 seem flow of EPA gas using a Lindberg/Blue 1" tube furnace. All gas flows to the reactor were controlled using Brooks mass flow controllers. After heating, the catalyst was allowed to cool to room temperature under 10 seem N2 flow. After cooling, the catalyst was exposed to various gas flow rates at various temperatures, as shown in Table 13. The gases used were 02 and EPA gas mix. Reaction conversions were measured for CO oxidation and NO reduction by GC-TCD according to the procedure described in example 8a-2. The results of this test are shown in Table 13.
Table 13. NO and CO conversion using CusSUSiC catalyst
Figure imgf000043_0001
[0059] Example 8e-3
[0060] A quartz glass sample tube that is sealed at one end was filled with a small amount (0.3010 g) of the as-prepared Cu3Si on SiC sample. The tube was then evacuated on a Schlenk line to 50 millitorr. The sample was then taken through a cycle of backfilling with argon, and evacuating to 50 millitorr a total of 3 times. The glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon. The sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed. XRD analysis indicated the presence of crystalline Cu3Si and Cu5Si, indicating that the Si remains associated with the copper on this support. A further test with 0.3007 g of the as-prepared Cu3Si on SiC sample sealed in a glass tube as described above and placed in a muffle furnace at 500°C for 168 hours, showed no further change. XRD also indicated the presence of Cu3Si and Cu5Si, so this SiC support appears to be able to support copper silicides with high temperature stability. A third test was undertaken with 0.2928 g of the as- prepared Cu3Si on SiC sample sealed in a glass tube as described above and placed in a muffle furnace at 1000°C for 87 hours. XRD indicated the presence of Cu3Si and Cu5Si, demonstrating stability at very high temperatures.
[0061] Example 8f-l
[0062] Cu3Si was impregnated into Si3N4 support (Cu3Si/Si3N4) via H2 reduction and subsequent SiH4 silicidation of CuO impregnated Si3N4. The samples were prepared by conventional incipient wetness impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of support were dried in air at 550 °C for 4 h. 11.50 mL of a 0.813 M aqueous solution of Οι(Ν03)2·3Η20 was added dropwise while stirring to 5.873 g of dried Si3N4 powder. The mixture was then placed in a vacuum oven (75 torr) and dried overnight at 120 °C. After drying, Cu loading was determined gravimetrically to be 9.2 wt% Cu. Next, 1.5022 g of sample was loaded into a ½" o.d. glass tube flow reactor and heated at 10 °C/min ramp under 50 seem air flow to 450 °C, where it was held and calcined for 5 hours. All gas flows were controlled with MKS mass flow controllers and the furnace used was a Lindberg/Blue 1" tube furnace. The reactor was then purged under argon flow at 495 seem and ramped at 10 °C/min to 500 °C. Then, a mixture of 5 seem H2 / 495 seem Ar was flowed over the sample to begin reduction. After 50 minutes, the mixture was changed to 5 seem H2 / 95 seem Ar. After an additional 15 minutes, the mixture was changed to 50 seem H2 and no argon flow. After 5 minutes, the reactor was allowed to cool to 200 °C under 50 seem flow of H2. Once at 200 °C, a mixture of 50 seem H2 and 50 seem of a 2% SiH4 in H2 was flowed over the sample for 20 hours. After reaction, the reactor was allowed to cool under 100 seem of argon flow. The sample was removed from the reactor and powder XRD analysis shows the crystalline composition of this material consists primarily of Cu3Si and Si3N4 with trace amounts of Cui5Si4 and CuO.
[0063] Example 8f-2
[0064] A quartz glass sample tube that is sealed at one end was filled with a small amount (0.1980 g) of the as-prepared Cu3Si and Si3N4 sample. The tube was then evacuated on a Schlenk line to 50 millitorr. The sample was then taken through a cycle of backfilling with argon, and evacuating to 50 millitorr a total of 3 times. The glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon. The sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed. XRD analysis indicated the presence of crystalline Cu3Si and Cu4Si, indicating that the Si remains associated with the copper on this support when exposed to high temperatures.
[0065] Example 8g-l
[0066] Cu3Si was impregnated into Davisil silica support (Cu3Si/Si02) via H2 reduction and subsequent SiH4 silicidation of CuO impregnated Si02. The samples were prepared by conventional incipient wetness impregnation using aqueous solutions of copper nitrate. Before impregnation, samples of support were dried in air at 550 °C for 4 h. 14.84 mL of a 2.16 M aqueous solution of Cu(N03)2-3H20 was added dropwise while stirring to 20.10 g of dried Si02 powder. The mixture was then placed in a vacuum oven (75 torr) and dried overnight at 120 °C. After drying, Cu loading was determined gravimetrically to be 9.2 wt% Cu. Next, 1.5045 g of sample was loaded into a ½" o.d. glass tube flow reactor and heated at 10 °C/min ramp under 50 seem air flow to 450 °C, where it was held and calcined for 5 hours. All gas flows were controlled with MKS mass flow controllers and the furnace used was a Lindberg/Blue 1" tube furnace. The reactor was then purged under argon flow at 495 seem and ramped at 10 °C/min to 500 °C. Then, a mixture of 5 seem H2 / 495 seem Ar was flowed over the sample to begin reduction. After 50 minutes, the mixture was changed to 5 seem H2 / 95 seem Ar. After an additional 15 minutes, the mixture was changed to 50 seem H2 and no argon flow. After 5 minutes, the reactor was allowed to cool to 200 °C under 50 seem flow of H2. Once at 200 °C, a mixture of 50 seem H2 and 50 seem of a 2% SiH4 in H2 was flowed over the sample for 20 hours. After reaction, the reactor was allowed to cool under 100 seem of argon flow. The sample was removed from the reactor and powder XRD analysis shows the formation of Cu3Si.
[0067] Example 8g-2
[0068] 0.23 g of as prepared Cu3Si on Si02 was loaded into a ¼" o.d. quartz glass tube insert that was then slid into the steel tube of a flow reactor for testing. The reactor was then heated to 500°C under 10 seem flow of EPA gas using a Lindberg/Blue 1" tube furnace. All gas flows to the reactor were controlled using Brooks mass flow controllers. After heating, the catalyst was allowed to cool to room temperature under 10 seem N2 flow. After cooling, the catalyst was exposed to various gas flow rates at various temperatures, as shown in Tables 14 and 15. The gases used were 02 and EPA gas mix. Reaction conversions were measured for CO oxidation, NO reduction, and hydrocarbon oxidation by GC-TCD according to the procedures described in examples 8a-2 and 8a-3. The results of this test are shown in Tables 14 and 15.
Table 14. NO and CO conversion using CuiSi/Si02 catalyst
Figure imgf000046_0001
Table 15. Propane conversion using CuiSi/Si02 catalyst
Figure imgf000046_0002
[0069] Example 8g-3
[0070] A quartz glass sample tube that is sealed at one end was filled with a small amount (0.1991 g) of the as-prepared Cu3Si on Si02 sample. The tube was then evacuated on a Schlenk line to 50 millitorr. The sample was then taken through a cycle of backfilling with argon, and evacuating to 50 millitorr a total of 3 times. The glass tube was then sealed with an oxygen - propane torch, such that the sample was contained in an airtight vial with 50 mtorr pressure of argon. The sample was then placed in a muffle furnace at 500°C for 87 hours. After cooling, the sample was removed from the glass tube and XRD analysis was performed. XRD analysis indicated the presence of crystalline, Cu3Si and Cu5Si, indicating that the Si remains associated with the copper on this support when exposed to high temperatures.
[0071] Example 9
[0072] 5.0086 g of CuO / A1203 beads containing 10 wt% Cu was loaded into the tube reactor described previously. The CuO /A1203 was prepared via the wet impregnation and calcination steps described previously. The sample was heated under 100 seem Ar flow to 500°C at 10°C/min. Once at 500°C, the Ar flow was turned off and 50 seem H2 was flowed over the sample for 2 hours. After this, 100 seem of 1% SiH4 in H2 was flowed over the catalyst at 500°C for 20 hours. Afterwards, the reactor was allowed to cool under 50 seem H2. A portion of the sample (a bead) was analyzed by SEM/EDS and found to have a silicon shell and a copper/alumina core. The silane had decomposed to Si and blocked the pores of the support, forming a shell and making the copper in the core inaccessible for further reaction.
[0073] While various embodiments of the present disclosure have been described in detail, it is apparent that modifications and adaptations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present disclosure.

Claims

CLAIMS What is claimed is:
1. A method comprising:
(a) combusting a substance, thereby producing an exhaust gas having a pollutant therein;
(i) wherein the pollutant comprises at least one of CO, NOx, plain hydrocarbons and oxygenated hydrocarbons;
(b) contacting the exhaust gas with a solid binary copper-silicon material;
(c) catalytically converting at least a portion of the pollutant into a product via the solid binary copper-silicon material.
2. The method of claim 1, wherein the combusting step (a) comprises combusting the substance in an internal combustion engine, thereby producing the exhaust gas; and wherein the method comprises:
flowing the exhaust gas from the internal combustion engine to an emission control device comprising the solid binary copper-silicon material.
3. The method of claim 1, wherein the solid binary copper-silicon material includes at least some Cu5Si.
4. The method of claim 1, wherein the solid binary copper-silicon material includes at least some Cu3Si.
5. The method of claim 1, wherein the solid binary copper-silicon material includes at least some copper-silicon solid solution.
6. The method of claim 1, wherein the solid binary copper-silicon material is in particulate form.
7. The method of claim 1, wherein, during the contacting step (b), the solid binary copper- silicon material is at a temperature that is from ambient to 220°C.
8. The method of any of the preceding claims, wherein the exhaust gas includes from 0.01 to 20 vol. % of the CO.
9. The method of any of the preceding claims, wherein the exhaust gas includes from 1 to 100,000 ppmv ofthe NOx.
10. The method of any of the preceding claims, wherein the exhaust gas includes at least 1 ppmv of at least one of the plain hydrocarbons and the oxygenated hydrocarbons.
11. An emission control device comprising: a housing having an waste gas inlet for receiving an exhaust gas and a treated gas outlet for discharging the exhaust gas, wherein the exhaust gas includes a pollutant when it enters the waste gas inlet;
wherein the pollutant comprises at least one of CO, NOx, plain hydrocarbons and oxygenated hydrocarbons; and
a solid binary copper-silicon material disposed in the housing and configured to communicate with the exhaust gas.
12. A method comprising:
(a) contacting copper metal particles of a porous high-surface area material with a silane-containing gas;
wherein the porous high-surface area material has an initial BET surface area of at least 0.1 m /gram;
wherein at least some of the copper metal particles are located within pores of the porous high-surface area material;
(b) reacting at least some of the copper metal with at least some of the silicon of the silane-containing gas, thereby forming binary copper-silicon material;
(c) recovering a final product having binary copper-silicon material within the pores of the porous high-surface area material, wherein the final product comprises from 0.01 to 80 wt. % Cu, and wherein the final product comprises a final BET surface area that is from 1% to 99% of the initial BET surface area.
13. The method of claim 12, wherein the final product consists essentially of the binary copper-silicon material and the porous high-surface area material.
14. The method of claim 12, wherein the method comprises maintaining the porous high- surface area material at a temperature of from 100°C to 350°C during the contacting (a) and reacting (b) steps.
15. The method of claim 14, wherein the method comprises maintaining an oxygen-free atmosphere during the contacting (a) and reacting (b) steps.
16. The method of claim 14, wherein the silane-containing gas consists of hydrogen (H2) gas and monosilane (SiH4) gas.
17. The method of claim 16, wherein the silane-containing gas contains 0.10 - 10.0 vol. % monosilane (SiH4).
18. The method of claim 12, wherein the binary copper-silicon material is selected from the group consisting of Cu3Si, Cu4Si, Cu5Si, Cu7Si, CU0. S10.1 , Cui5Si4, copper-silicon solid solution, and mixtures thereof.
19. The method of claim 12, wherein the binary copper-silicon material is Cu3Si.
20. The method of claim 12, comprising, prior to the contacting step (a):
forming the copper metal particles on surfaces of the porous high-surface area material.
21. The method of claim 20, wherein the forming comprises at least one of (i) precipitating the copper metal particles within pores of the porous high-surface area material, and (ii) infiltrating the pores of the porous high-surface area material with a copper precursor solution comprising a copper precursor.
22. The method of claim 21, wherein the forming comprises the precipitating step, and wherein the precipitating comprises co -precipitating the copper metal particles and the porous high-surface area material in a bath.
23. The method of claim 21, wherein the forming comprises the precipitating step, and wherein the precipitating step comprises precipitating the copper metal particles in a bath comprising the porous high-surface area material.
24. The method of claim 21, wherein the forming comprises the infiltrating step, and wherein the infiltrating step comprises at least one of wet impregnation, spray drying and incipient wetness impregnation.
25. The method of claim 20, wherein the method comprises maintaining the porous high- surface area material in a reducing environment between the forming step and the contacting step (a).
26. The method of claim 25, wherein the forming step comprises reducing the copper precursor to the copper metal particles using a reducing agent.
27. The method of claim 20, comprising, after the forming step and prior to the contacting step (a), regulating the temperature of the porous high-surface area material to a temperature of from 100°C to 350°C.
28. The method of claim 20, wherein the forming step comprises:
infiltrating pores of the porous high-surface area material with a copper precursor solution comprising a copper precursor;
drying the porous high-surface area material, thereby removing solvent of the copper precursor solution and depositing copper precursor at least within pores of the porous high- surface area material; and oxidizing the copper precursor to copper oxide particles, wherein at least some of the copper oxide particles are at least located within pores of the porous high-surface area material.
29. The method of claim 28, wherein the oxidizing comprises calcining the porous high- surface area material, wherein the calcining occurs at a temperature higher than the decomposition temperature of the copper precursor, and wherein the calcining occurs at a temperature below the sintering point of the copper oxide particles.
30. The method of claim 29, wherein the copper precursor comprises copper nitrate, and wherein the calcining step occurs at a temperature of from 300° to 600°C.
31. The method of claim 28, wherein the forming step comprises:
reducing the copper oxide particles to copper metal particles via a reducing gas.
32. The method of claim 31, wherein the reducing gas is a hydro gen- containing (H2) gas.
33. The method of claim 31, wherein the method comprises, prior to the reducing step, heating the porous high- surface area material with an inert gas.
34. The method of claim 31, wherein the reducing step comprises first exposing the porous high-surface area material to a first reducing gas having a first concentration of a reducing agent, and then second exposing the porous high-surface area material to a second reducing gas having a second concentration of a reducing agent, wherein the second concentration is larger than the first concentration.
35. The method of claim 31, comprising, after the reducing step:
regulating the porous high-surface area material to a temperature of from 100°C to 350°C, and then completing the contacting step (a).
36. The method of claim 35, wherein the regulating step comprises exposing the porous high-surface area material to a hydrogen-containing gas.
37. The method of claim 20, wherein after the forming and prior to the converting step (a), the method comprises:
exposing the porous high-surface area material comprising the copper metal to a reducing environment, thereby removing oxides present on surfaces of the copper metal particles.
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