WO2022065188A1 - Methane oxidation catalyst, methane oxidation multilayer catalyst, exhaust gas purification system using said methane oxidation catalyst or said methane oxidation multilayer catalyst, and method for producing methane oxidation catalyst - Google Patents

Methane oxidation catalyst, methane oxidation multilayer catalyst, exhaust gas purification system using said methane oxidation catalyst or said methane oxidation multilayer catalyst, and method for producing methane oxidation catalyst Download PDF

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WO2022065188A1
WO2022065188A1 PCT/JP2021/034080 JP2021034080W WO2022065188A1 WO 2022065188 A1 WO2022065188 A1 WO 2022065188A1 JP 2021034080 W JP2021034080 W JP 2021034080W WO 2022065188 A1 WO2022065188 A1 WO 2022065188A1
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methane oxidation
alumina
catalyst
methane
base material
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PCT/JP2021/034080
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French (fr)
Japanese (ja)
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靖幸 伴野
大成 伊藤
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エヌ・イーケムキャット株式会社
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Publication of WO2022065188A1 publication Critical patent/WO2022065188A1/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
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • 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
    • 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
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B01J35/60—
    • 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
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust

Definitions

  • the present invention relates to a methane oxidation catalyst for oxidizing methane contained in gas, a methane oxidation laminated catalyst, an exhaust gas purification system using these, a method for producing a methane oxidation catalyst, and the like.
  • CNG compressed natural gas
  • LNG liquefied natural gas
  • city gas city gas
  • light oil kerosene, etc.
  • CO carbon monoxide
  • NO nitrogen monoxide
  • NOx nitrogen oxides
  • SOx sulfur oxides
  • HC unburned hydrocarbons
  • the exhaust gas emitted from a lean combustion gas engine such as a cogeneration system or a gas heat pump (GHP), and a bi-fuel engine (BF) or a dual fuel engine (BF) or a dual fuel engine in which CNG or LNG is used in combination with gasoline or light oil
  • a lean combustion gas engine such as a cogeneration system or a gas heat pump (GHP)
  • BF bi-fuel engine
  • BF dual fuel engine
  • a dual fuel engine in which CNG or LNG is used in combination with gasoline or light oil
  • the exhaust gas emitted from CNG-DFCI, LNG-DFCI, etc. may also contain a trace amount of methane.
  • platinum group elements such as platinum, palladium, and rhodium are supported on aluminum base material particles as catalytically active components, for example, Pd-supported alumina and Pt / Pd. Supported alumina and the like are known (see, for example, Patent Documents 1 to 3).
  • the catalysts described in Patent Documents 1 to 3 have a problem that they act in a high temperature region of, for example, 500 ° C. or higher and have low catalytic activity in a low temperature region of less than 500 ° C., and the oxidative activity of methane in such a low temperature region is high. Improvement is required.
  • the catalyst described in Patent Document 4 is found to have improved methane oxidation activity in the low temperature region as compared with the catalysts of Patent Documents 1 to 3, but the degree of improvement is not sufficient and there is still room for improvement. Further, since the catalyst described in Patent Document 5 uses tin, which can be a biological poison due to chemical action with organic compounds, ash, etc., from the viewpoint of safety during manufacturing and use, impact on the environment, etc. Therefore, the development of alternative products is required.
  • the present invention has been made in view of the above problems.
  • the purpose is to provide a novel methane oxidation catalyst, a methane oxidation laminated catalyst, an exhaust gas purification system using these, a method for producing a methane oxidation catalyst, etc., in which the methane catalyst activity is enhanced in a low temperature region of less than 500 ° C. To do.
  • the present inventors have diligently studied to solve the above problems. As a result, they have found that the above problems can be solved by using a composite catalyst in which Pd and Ni are supported on alumina-based base material particles, and have completed the present invention.
  • a methane oxidation catalyst for oxidizing methane contained in a gas which comprises alumina-based base material particles and composite particles containing Pd and Ni supported on the alumina-based base material particles.
  • Methane oxidation catalyst for oxidizing methane contained in a gas, which comprises alumina-based base material particles and composite particles containing Pd and Ni supported on the alumina-based base material particles.
  • alumina-based base metal particles include at least one selected from the group consisting of alkali metal elements, alkaline earth metal elements, transition elements, and rare earth elements.
  • a methane oxidation laminated catalyst for oxidizing methane contained in a gas comprising a catalyst carrier and a catalyst layer supported on the catalyst carrier, wherein the catalyst layer is an alumina-based base metal particle.
  • a methane oxidation laminated catalyst comprising a methane oxidation catalyst containing composite particles containing Pd and Ni supported on the alumina-based base metal particles.
  • the methane oxidation laminated catalyst further has the technical features described in any one of the above [1] to [10].
  • a methane oxidation catalyst containing alumina-based base material particles and composite particles containing Pd and Ni supported on the alumina-based base material particles is arranged in the exhaust gas flow path of the exhaust gas discharged from the internal combustion engine.
  • an exhaust gas purification system is arranged in the exhaust gas flow path of the exhaust gas discharged from the internal combustion engine.
  • this exhaust gas purification system it is preferable that this exhaust gas purification system further has the technical features described in any one of the above [1] to [14].
  • Alumina-based base material particles are immersed in a solution containing Pd salt and Ni salt, Pd and Ni are co-supported on the alumina-based base material particles, and Pd and Ni are placed on the alumina-based base material particles.
  • a method for producing a methane oxidation catalyst which forms composite particles on which the particles are supported.
  • the method for producing the methane oxidation catalyst further has the technical features described in any one of the above [1] to [10].
  • a novel methane oxidation catalyst having enhanced methane catalytic activity in a low temperature region of less than 500 ° C., a methane oxidation laminated catalyst, an exhaust gas purification system using these, a method for producing a methane oxidation catalyst, etc. can be realized.
  • Example 6 is a graph showing the particle diameters of Pd particles on the aluminum-based base material particles of Examples 2, 6 and 7, and Comparative Example 1. It is a graph which shows the methane oxidation removal performance of Examples 10-11. It is a graph which shows the methane oxidation removal performance of Examples 7, 12 to 16.
  • the methane oxidation catalyst 100 of the present embodiment is an oxidation catalyst for oxidizing methane contained in the gas, and is a Pd supported on the alumina-based base material particles 11 and the surface 11a of the alumina-based base material particles 11. It is characterized by containing composite particles 21 containing Ni and Ni.
  • the alumina-based base material particles 11 are particles containing alumina as a constituent component, and are carrier particles that support Pd and Ni on the surface 11a thereof.
  • alumina means aluminum oxide such as ⁇ -alumina, ⁇ -alumina, ⁇ -alumina, and ⁇ -alumina, as well as boehmite [ ⁇ -AlO (OH)] and diaspoa [ ⁇ -AlO ( ⁇ -AlO). OH)] and the like are aluminum oxide hydroxides or alumina hydrates Al 2 O 3 ⁇ n (H 2 O)) and the like.
  • alumina one type can be used alone, or two or more types can be used in any combination and ratio.
  • alumina ⁇ -alumina, ⁇ -alumina, and boehmite are preferable.
  • alkali metal elements such as potassium and sodium, alkaline earth metal elements such as barium and magnesium, transition elements such as iron, cobalt and titanium, cerium, lanthanum, neodymium and zirconium, It may contain other components such as rare earth elements such as praseodymium. However, these contents are preferably 30% by mass or less from the viewpoint of maintaining a high BET specific surface area of the alumina-based base material particles 11.
  • one kind may be used alone, or two or more kinds may be used in any combination and ratio.
  • the particle shape of the alumina-based base material particles 11 is not particularly limited, and may be, for example, spherical, ellipsoidal, crushed, flat, indefinite, or the like.
  • the average particle diameter (D50) of the alumina-based base material particles 11 can be appropriately set according to the desired performance, and is not particularly limited, but maintains a large specific surface area and enhances heat resistance to increase the number of its own catalytically active sites. From the viewpoint of allowing the particles to grow, the thickness is preferably 5 to 200 ⁇ m, more preferably 10 to 150 ⁇ m, and even more preferably 15 to 100 ⁇ m.
  • the average particle size D50 means a median diameter measured by a laser diffraction type particle size distribution measuring device (for example, a laser diffraction type particle size distribution measuring device SALD-7100 manufactured by Shimadzu Corporation).
  • the pore diameter of the alumina-based base material particles 11 used here can be appropriately set according to the desired performance and is not particularly limited, but is 5 nm or more and 30 nm or less from the viewpoint of improving the catalytic activity of methane in a low temperature region of less than 500 ° C. Is more preferable, and more preferably 7 nm or more and 29 nm or less, and further preferably 10 nm or more and 28 nm or less.
  • the pore diameter of the alumina-based base material particles 11 means a value calculated by the mercury intrusion method.
  • the pore volume is measured under the conditions described in Examples described later, and the value of the peak top position in the pore distribution curve of the pore diameter-differential pore volume obtained at this time is set as the alumina-based base material particles.
  • the pore diameter is 11.
  • the pore volume of the alumina-based base material particles 11 can be appropriately set according to the desired performance and is not particularly limited, but is preferably 1.0 cc / g or more and 3.0 cc / g or less, and more preferably 1.2 cc / g. It is g or more and 2.8 cc / g or less, more preferably 1.5 cc / g or more and 2.5 cc / g or less.
  • the pore volume of the alumina-based base material particles 11 means a value calculated by the mercury intrusion method. Here, the pore volume is measured under the conditions described in Examples described later.
  • Pd and Ni are supported as catalytically active components on the surface 11a of the above-mentioned alumina-based base material particles 11.
  • the Pd and Ni on the surface 11a of the alumina-based base material particles 11 can change to a simple substance of a metal, an oxide, or the like depending on the external environment. Therefore, the oxidation state of Pd and Ni is not particularly limited, but it is preferably particles in a reducing atmosphere.
  • the molar ratio (Pd / Ni) of Pd and Ni contained in the composite particle 21 can be appropriately set according to the desired performance and is not particularly limited, but is preferably 0.25/1 to 1/5, more preferably 0. .5 / 1 to 1/4, more preferably 1/1 to 1/3.
  • the content of Pd and Ni supported on the alumina-based base material particles 11 can be appropriately determined according to the desired performance and is not particularly limited, but is not particularly limited, but is a composite particle from the viewpoint of improving the low temperature catalytic activity below 500 ° C.
  • the metal equivalent amount with respect to the total amount of 21 is preferably 3 to 20% by mass, more preferably 4 to 17% by mass, and further preferably 5 to 15% by mass, respectively.
  • the average particle diameter (D50) of Pd on the surface 11a of the alumina-based base material particles 11 is preferably 0.5 nm or more and 3.0 nm or less, more preferably 0.7 nm or more and 2.5 nm or less, and further preferably 0.9 nm. It is 2.0 nm or less.
  • the composite particles 21 do not substantially contain mercury, lead, tin, zinc, and oxides thereof. These can be biotoxic due to chemical action with organic compounds, ash and the like. Therefore, the content ratio of mercury, lead, tin, zinc, and their oxides is preferably less than 10% by mass, more preferably less than 3% by mass, still more preferably 1 in terms of metal equivalent to the total amount of the composite particles 21. It is less than mass%, particularly preferably less than 0.5% by mass, and most preferably less than 0.1% by mass.
  • the methane oxidation catalyst 100 of the present embodiment may contain other components as long as it contains the above-mentioned composite particles 21.
  • the other components include catalytically active components other than Pd and Ni (hereinafter, may be simply referred to as “other catalytically active components”), and base material particles other than the above-mentioned alumina-based base material particles 11. In the above, it may be simply referred to as "other base material particles”) and the like.
  • Examples of other catalytically active components include platinum group elements other than Pd, specifically platinum (Pt), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os).
  • platinum group elements one type may be used alone, or two or more types may be used in any combination and ratio.
  • Other base material particles include alumina-based particles in which Pd and / or Ni are not supported, metal oxides such as ceria and zirconia; zirconia and ceria-zirconia doped with rare earth elements and / or transition elements, and the like.
  • the proportion of these other catalytically active components and other base metal particles used is not particularly limited, but is preferably 0.01 to 30% by mass in total, and more preferably in total, with respect to the total amount of the methane oxidation catalyst 100. It is 0.01 to 15% by mass, more preferably 0.01 to 5% by mass in total.
  • the methane oxidation catalyst 100 of the present embodiment may contain additives known in the art in addition to the above-mentioned composite particles 21 and other components.
  • the additive include, but are not limited to, various binders, dispersion stabilizers such as nonionic surfactants and anionic surfactants, pH adjusters, viscosity adjusters and the like.
  • the proportion of these additives used is not particularly limited, but is preferably 0.01 to 10% by mass in total, more preferably 0.05 to 8% by mass in total, and total to the total amount of the methane oxidation catalyst 100. It is more preferably 0.1 to 5% by mass.
  • the above-mentioned composite particles 21 can be produced according to a conventional method, and the production method thereof is not particularly limited. From the viewpoint of reproducibility, simplicity, and low cost, the evaporation-drying method (impregnation method, spray-drying method, etc.) is preferable.
  • the alumina-based base material particles 11 (hereinafter, may be referred to as “raw material alumina powder”) is immersed in a solution containing a Pd salt, and Pd is supported on the surface 11a of the alumina-based base material particles 11. Then, the composite particles 21 can be obtained by further immersing the particles in a solution containing a Ni salt and supporting Ni on the surface 11a of the alumina-based base material particles 11.
  • Pd ions and / or Ni ions are adsorbed (adhered) to the surface 11a of the alumina-based base material particles 11 in a highly dispersed state.
  • the order in which Pd and Ni are supported can be reversed.
  • the alumina-based base material particles 11 are immersed in a solution containing a Pd salt and a Ni salt, and alumina is used. A method of co-supporting Pd and Ni on the surface 11a of the system base material particles 11 can be mentioned.
  • the BET specific surface area of the raw material alumina powder is not particularly limited, but can be appropriately set depending on the high dispersion support of Pd and Ni, gas diffusivity, etc., and is not particularly limited, but is preferably 10 to 400 m 2 / g, more preferably. Is 20 to 350 m 2 / g, more preferably 50 to 300 m 2 / g.
  • As the alumina powder many grades are commercially available from domestic and overseas manufacturers, and the commercially available products of various grades can be used as the alumina-based base material particles 11 (raw material alumina powder) of the present embodiment. can. Further, the above-mentioned alumina-based base material particles 11 (raw material alumina powder) can also be produced by a method known in the art.
  • the solution containing the Pd salt and / or the Ni salt is not particularly limited, but the Pd salt and / or the Ni salt and other components and additives to be blended as necessary are mixed with water, and the Pd salt and / or A Ni salt-containing aqueous solution is preferably used.
  • the form of the salt used here may be selected according to a conventional method and is not particularly limited, but is generally limited to hydrochloride, oxyhydrochloride, nitrate, oxynitrate, carbonate, phosphate, acetate and shu. Acidates, citrates, ammine complex salts and the like are preferred.
  • the content ratio of Pd ion and / or Ni ion in the aqueous solution can be appropriately adjusted so that the content ratio of Pd and Ni in the obtained methane oxidation catalyst 100 is a desired content ratio, and is not particularly limited.
  • the above-mentioned alumina-based base material particles 11 (raw material alumina powder) are impregnated or immersed in such a solution to remove the solvent (for example, water), and if necessary, a drying treatment and / or about 200 to 600 ° C.
  • the heat treatment (firing treatment) of the above the composite particles 21 containing Pd and Ni supported on the surface 11a of the alumina-based base material particles 11 can be obtained with good productivity.
  • the firing conditions may be in accordance with a conventional method and are not particularly limited.
  • the firing atmosphere may be any of an oxidizing atmosphere, a reducing atmosphere, and a neutral atmosphere. From the viewpoint of productivity and the like, generally, it is preferably 0.1 to 12 hours at 150 ° C to 1300 ° C, and more preferably 0.1 to 4 hours at 350 ° C to 600 ° C.
  • vacuum drying may be performed using a vacuum dryer or the like, and drying treatment may be performed at about 50 ° C. to 200 ° C. for about 1 to 48 hours.
  • the obtained composite particle 21 has a composite structure in which Pd and Ni are co-supported on the surface 11a of the alumina-based base particle 11, and these Pd and Ni function as main catalytically active sites.
  • the particle size of the composite particles 21 may be adjusted according to the required performance.
  • the particle size of the composite particle 21 can be adjusted according to a conventional method, and is not particularly limited.
  • the composite particles 21 are preferably wet-milled to have an average particle diameter (D90) of 3 to 50 ⁇ m, more preferably 5 to 40 ⁇ m, and even more preferably 10 to 30 ⁇ m. ..
  • the methane oxidation catalyst 100 of the present embodiment exhibits a catalytic ability to oxidize (oxidize and remove) methane by exposing the composite particles 21 to a gas containing methane.
  • the form of use of the methane oxidation catalyst 100 is not particularly limited. For example, it can be used as it is in the form of the catalyst powder which is an aggregate of the composite particles 21 described above. Further, for example, the composite particles 21 can be molded into an arbitrary shape to obtain a granular or pellet-shaped molding catalyst.
  • various known dispersion devices, kneading devices, and molding devices can be used.
  • the methane oxidation catalyst 100 of the present embodiment can also be used in a form of being supported on a catalyst carrier such as a monolith carrier.
  • This form can be defined as a laminated catalyst comprising a catalyst carrier and a catalyst layer containing a methane oxidation catalyst 100 (composite particles 21) supported on the catalyst carrier.
  • the catalyst area of the laminated catalyst may be a single layer having only one catalyst layer or a laminated body composed of two or more catalyst layers, and is known in the art as one or more catalyst layers. It may be any of the laminated bodies in which one or more other layers are combined.
  • a catalyst carrier known in the art can be appropriately selected.
  • Typical examples thereof include ceramic monolith carriers made of cordierite, silicon carbide, silicon nitride and the like, metal honeycomb carriers made of stainless steel and the like, wire mesh carriers made of stainless steel and the like, but are not particularly limited thereto. It should be noted that these can be used alone or in any combination and ratio of two or more.
  • the method for forming the catalyst layer may be performed according to a conventional method, and is not particularly limited. Various known coating methods, wash coat methods, and zone coat methods can be applied.
  • the methane oxidation catalyst 100 of the present embodiment of the present embodiment an aqueous medium, and optionally a binder known in the art, other catalysts, co-catalyst particles, OSC material, base material particles, addition.
  • a slurry-like mixture can be prepared by mixing the agent and the like in a desired blending ratio, and the obtained slurry-like mixture can be applied to the surface of the catalyst carrier, dried and fired.
  • an acid or a base can be blended for pH adjustment, or a surfactant, a dispersion resin, or the like for adjusting the viscosity or improving the slurry dispersibility can be blended.
  • a surfactant, a dispersion resin, or the like for adjusting the viscosity or improving the slurry dispersibility can be blended.
  • pulverization and mixing using a ball mill or the like can be applied, but other pulverization or mixing methods can also be applied.
  • the catalyst layer containing the methane oxidation catalyst 100 of the present embodiment is provided on the catalyst carrier by drying and firing according to a conventional method (methane oxidation laminated catalyst). ) Can be obtained.
  • the coating amount of the methane oxidation catalyst 100 can be appropriately set according to the desired performance and is not particularly limited, but is 100 g / L or more with respect to 1 L of the catalyst carrier as a base material from the viewpoint of the coating amount and pressure loss. It is preferably 200 g / L or less, more preferably 100 g / L or more and 180 g / L or less, and further preferably 110 g / L or more and 150 g / L or less.
  • the coating amount of Pd can be appropriately set according to the desired performance and is not particularly limited, but is preferably 4.5 g / L or more and 16.0 g / L or less with respect to 1 L of the catalyst carrier as a base material. It is more preferably 5.0 g / L or more and 14.0 g / L or less, and further preferably 6.0 g / L or more and 12.0 g / L or less.
  • the amount of Ni coated can be appropriately set according to the desired performance and is not particularly limited, but is preferably 1.0 g / L or more and 11.0 g / L or less with respect to 1 L of the catalyst carrier as a base material. It is more preferably 2.0 g / L or more and 9.5 g / L or less, and further preferably 5.0 g / L or more and 8.0 / L or less.
  • the methane oxidation catalyst 100 of the present embodiment is useful as an oxidation catalyst for oxidizing methane contained in the gas.
  • oxidation catalyst for oxidizing methane contained in the gas.
  • the oxidation catalyst of methane contained in the gas discharged from the gas such as, the methane oxidation catalyst 100 of the present embodiment can be used.
  • the methane oxidation catalyst 100 of the present embodiment is exhaust gas discharged from a compressed ignition internal combustion engine such as a diesel engine, a bi-fuel engine (BF) or a dual fuel engine (CNG-DFCI, LNG-DFCI, etc.) using the compressed ignition internal combustion engine. It is particularly useful as an oxidation catalyst for methane contained in.
  • a compressed ignition internal combustion engine such as a diesel engine, a bi-fuel engine (BF) or a dual fuel engine (CNG-DFCI, LNG-DFCI, etc.
  • DOC diesel oxidation catalyst
  • DOC particulate substance such as soot contained in the exhaust gas
  • Diesel Particulate Filler for collecting PM: Particulate matter, Catalyzed Particulate Filler (CPF) or Catalyzed Soot Filter (CSF); Lean condition A lean NOx particulate filter (LNT, Lean NOx Trap) that absorbs NOx underneath and releases NOx under rich conditions to oxidize CO and HC to CO 2 and H 2 O and reduce NOx to N 2 . It can be carried out by appropriately providing a catalytic reduction (SCR: Selective Catalytic Reduction catalyst); an ammonia oxidation catalyst (AMOX: Ammonia Oxidation catalyst) or the like. The arrangement order and the number of these arrangements can be appropriately changed according to the required performance, and are not limited to the above example.
  • SCR Selective Catalytic Reduction catalyst
  • AMOX ammonia oxidation catalyst
  • the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. That is, the materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention.
  • the values of various production conditions and evaluation results in the following examples have meanings as preferable values of the upper limit or the lower limit in the embodiment of the present invention, and the preferable range is the preferable value of the upper limit or the lower limit described above.
  • the preferred range may be a range defined by a combination of the above-mentioned upper limit or lower limit value and the value of the following examples or the values of the examples.
  • the pore distribution of the alumina-based base material particles 11 is determined by the mercury intrusion method.
  • 110.2 g of alumina-based base material particles are used as a sample, and a mercury porosimeter (manufactured by Thermo Fisher Scientific, trade names: PASCAL140 and PASCAL440) is used under the conditions of a mercury contact angle of 130 ° and a surface tension of 484 dyn / cm.
  • the pore volume is measured below, and the value (mode diameter) of the peak top position in the pore distribution curve of the pore diameter-differential pore volume obtained at this time is taken as the pore diameter of the alumina-based base material particles 11.
  • Average particle diameter D50 of alumina-based base material particles 11 The particle size distribution is measured using a laser diffraction type particle size distribution measuring device (for example, a laser diffraction type particle size distribution measuring device SALD-7100 manufactured by Shimadzu Corporation), and the median diameter thereof is the average particle size of the alumina-based base material particles 11. Let it be D50.
  • a laser diffraction type particle size distribution measuring device for example, a laser diffraction type particle size distribution measuring device SALD-7100 manufactured by Shimadzu Corporation
  • BET specific surface area For the BET specific surface area, use a specific surface area / pore distribution measuring device (trade name: BELSORP-mini II, manufactured by Microtrac Bell Co., Ltd.) and analysis software (trade name: BEL_Master, manufactured by Microtrac Bell Co., Ltd.). Then, the BET specific surface area is obtained by the BET one-point method.
  • BELSORP-mini II manufactured by Microtrac Bell Co., Ltd.
  • analysis software trade name: BEL_Master, manufactured by Microtrac Bell Co., Ltd.
  • Example 1 Alumina-based base particle (manufactured by Sasol, trade name: TH100 / 150, BET specific surface area: 150 m 2 / g, average particle diameter D50: 32 ⁇ m, pore diameter (peak value): 17.2 nm, pore volume: 1.82 cc / G) was used.
  • An aqueous solution of Pd nitrate and an aqueous solution of nickel (II) nitrate hexahydrate were mixed to prepare an aqueous solution containing a Pd salt and a Ni salt (containing 3.6% by mass in terms of Pd and 1.6% by mass in terms of Ni). ..
  • the aqueous solution containing the Pd salt and the Ni salt is impregnated with the above alumina-based base material particles to co-support Pd and Ni on the alumina-based base material particles, and then fired at 500 ° C. for 1 hour.
  • the particles are kneaded by a wet milling method until the average particle diameter D90 is within the range of 14 to 18 ⁇ m, and the methane oxidation of Example 1 is carried out.
  • a catalyst (containing 3.0% by mass in terms of Pd and 1.6% by mass in terms of Ni) was obtained.
  • Comparative Example 1 The same procedure as in Example 1 was carried out except that the use of the Nitric acid Nitric acid aqueous solution was omitted, to obtain the methane oxidation catalyst of Comparative Example 1 (containing 3.0% by mass in terms of Pd).
  • Example 2 The same procedure as in Example 1 was carried out except that an aqueous solution of tetraammine platinum (II) nitrate was used instead of the aqueous solution of Ni nitric acid. (Containing 0% by mass) was obtained.
  • II tetraammine platinum
  • Example 3 The same procedure as in Example 1 was carried out except that an aqueous solution of cerium (IV) nitrate hexahydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 3 (containing 3.0% by weight in Pd conversion, converted to Ce). (Containing 10.0% by mass) was obtained.
  • Example 4 The same procedure as in Example 1 was carried out except that an aqueous solution of magnesium (II) nitrate hexahydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 4 (containing 3.0% by mass in terms of Pd, converted to Mg). (Containing 0.7% by mass) was obtained.
  • an aqueous solution of magnesium (II) nitrate hexahydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 4 (containing 3.0% by mass in terms of Pd, converted to Mg). (Containing 0.7% by mass) was obtained.
  • Example 5 The same procedure as in Example 1 was carried out except that an aqueous solution of cobalt (II) nitrate hexahydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 5 (containing 3.0% by mass in terms of Pd, converted to Co). (Containing 1.7% by mass) was obtained.
  • an aqueous solution of cobalt (II) nitrate hexahydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 5 (containing 3.0% by mass in terms of Pd, converted to Co). (Containing 1.7% by mass) was obtained.
  • Example 6 The same procedure as in Example 1 was carried out except that an aqueous solution of barium (II) acetate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 6 (containing 3.0% by mass in terms of Pd and 3.9 in terms of Ba). (Containing% by mass) was obtained.
  • Example 7 The same procedure as in Example 1 was carried out except that an aqueous solution of copper (II) nitrate trihydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 7 (containing 3.0% by mass in terms of Pd, converted to Cu). (Containing 1.8% by mass) was obtained.
  • Example 8 The same procedure as in Example 1 was carried out except that an aqueous solution of iron (III) nitrate hydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 8 (containing 3.0% by mass in terms of Pd, converted to Fe). (Containing 1.6% by mass) was obtained.
  • Example 9 The same procedure as in Example 1 was carried out except that an aqueous solution of yttrium (III) nitrate hexahydrate was used instead of the aqueous solution of Ni nitric acid, and the methane oxidation catalyst of Comparative Example 9 (containing 3.0% by mass in Pd conversion, converted to Y). (Containing 2.5% by mass) was obtained. Used as.
  • Example 10 The same procedure as in Example 1 was carried out except that an aqueous solution of cerium (IV) nitrate hexahydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 10 (containing 3.0% by mass in terms of Pd, converted to Ce). (Containing 3.9% by mass) was obtained.
  • Comparative Example 11 The same procedure as in Example 1 was carried out except that a praseodymium nitrate (III) hexahydrate aqueous solution was used instead of the Nitric acid Nitric acid aqueous solution, and the methane oxidation catalyst of Comparative Example 11 (containing 3.0% by mass in Pd conversion, Pr conversion). (Containing 4.0% by mass) was obtained.
  • a praseodymium nitrate (III) hexahydrate aqueous solution was used instead of the Nitric acid Nitric acid aqueous solution, and the methane oxidation catalyst of Comparative Example 11 (containing 3.0% by mass in Pd conversion, Pr conversion). (Containing 4.0% by mass) was obtained.
  • Comparative Example 12 The same procedure as in Example 1 was carried out except that an aqueous solution of neodymium (III) nitrate hexahydrate was used instead of the aqueous solution of Ni nitric acid, and the methane oxidation catalyst of Comparative Example 12 (containing 3.0% by mass in Pd conversion, converted to Nd). (Containing 4.1% by mass) was obtained.
  • Example 2 An aqueous solution containing a Pd salt and a Ni salt obtained by mixing an aqueous solution of Pd nitrate and an aqueous solution of nickel (II) nitrate hexahydrate (containing 3.6% by mass in terms of Pd and 2.0% by mass in terms of Ni).
  • Alumina-based base particle (manufactured by Sasol, trade name: TH100 / 150, BET specific surface area: 150 m 2 / g, average particle diameter D50: 32 ⁇ m, pore diameter (peak value): 17.2 nm, pore volume: 1 .82cc / g) was impregnated to co-support Pd and Ni on the alumina-based base material particles, and then fired at 450 ° C. for 0.5 hours to cause Pd and Ni on the alumina-based base material particles.
  • the particles were kneaded by a wet milling method until the average particle diameter D90 was within the range of 14 to 18 ⁇ m, and the methane oxidation catalyst of Example 2 (containing 3.6% by mass in terms of Pd) was kneaded. , 2.0% by mass in terms of Ni) was obtained.
  • the obtained methane oxidation catalyst of Example 2 was wet-coated on a cordierite carrier (manufactured by NGK, ⁇ 25.4 x 50 mm) (coating amount: 125 g / L, Pd equivalent coating amount: 4.5 g / L,
  • the methane oxidation laminated catalyst of Example 2 was obtained by firing treatment at 450 ° C. for 30 minutes at a Ni equivalent coating amount: 2.5 g / L).
  • the alumina-based base particle to be used is an alumina-based base particle (manufactured by Sasol, trade name: Silarox 1.5 / 100, BET specific surface area: 100 m 2 / g, average particle diameter D50: 37 ⁇ m, pore diameter (peak value) :.
  • the same procedure as in Example 2 was carried out except that the particle volume was changed to 11.6 nm and the pore volume: 0.46 cc / g) to obtain the methane oxide laminated catalyst of Example 3.
  • the alumina-based base particle to be used is an alumina-based base particle (manufactured by Solvay, trade name: MI386, BET specific surface area: 200 m 2 / g, average particle diameter D50: 22 ⁇ m, pore diameter (peak value): 10.4 nm, The same procedure as in Example 2 was carried out except that the pore volume was changed to 1.00 cc / g) to obtain the methane oxide lamination catalyst of Example 4.
  • the alumina-based base particle to be used is an alumina-based base particle (manufactured by Sasol, trade name: TH130 / 130, BET specific surface area: 130 m 2 / g, average particle diameter D50: 22 ⁇ m, pore diameter (peak value): 26.
  • the same procedure as in Example 2 was carried out except that the particle volume was changed to 2 nm and the pore volume: 2.29 cc / g) to obtain the methane oxide lamination catalyst of Example 5.
  • Example 6 The same procedure as in Example 2 was carried out except that the amount of supported Ni was changed to 3 times the amount of supported Pd, and the methane oxidation catalyst of Example 6 (containing 3.6% by mass in Pd conversion, 6.0 in Ni conversion) was carried out. (Containing% by mass) was obtained.
  • the obtained methane oxidation catalyst of Example 6 was wet-coated on a cordierite carrier ( ⁇ 25.4 x 50 mm) (coating amount: 125 g / L, Pd equivalent coating amount: 4.5 g / L, Ni equivalent coating). Amount: 7.4 g / L) and firing treatment at 450 ° C. for 30 minutes to obtain the methane oxidation laminated catalyst of Example 6.
  • the alumina-based base particle to be used is an alumina-based base particle (manufactured by Sasol, trade name: TH130 / 130, BET specific surface area: 130 m 2 / g, average particle diameter D50: 22 ⁇ m, pore diameter (peak value): 26.
  • the same procedure as in Example 6 was carried out except that the particle volume was changed to 2 nm and the pore volume: 2.29 cc / g) to obtain the methane oxide lamination catalyst of Example 7.
  • the alumina-based base particle to be used is an alumina-based base particle (manufactured by Sasol, trade name: TH100 / 100, BET specific surface area: 100 m 2 / g, average particle diameter D50: 29 ⁇ m, pore diameter (peak value): 26.
  • the same procedure as in Example 6 was carried out except that the particle volume was changed to 7 nm and the pore volume: 1.78 cc / g) to obtain the methane oxide lamination catalyst of Example 8.
  • the alumina-based base particle to be used is an alumina-based base particle (manufactured by Sasol, trade name: TM100 / 150, BET specific surface area: 150 m 2 / g, average particle diameter D50: 27 ⁇ m, pore diameter (peak value): 24.
  • the same procedure as in Example 6 was carried out except that the particle volume was changed to 8 nm and the pore volume: 1.60 cc / g) to obtain the methane oxide lamination catalyst of Example 9.
  • Example 10 Alumina-based base material particles (manufactured by Sasol, trade name) in an aqueous solution containing a Pd salt and a Ni salt obtained by mixing an aqueous solution of tetraammine palladium (II) chloride hydrate and an aqueous solution of nickel (II) nitrate hexahydrate. : TH100 / 150, BET specific surface area: 150 m 2 / g, average particle diameter D50: 32 ⁇ m, pore diameter (peak value): 17.2 nm, pore volume: 1.82 cc / g) to impregnate the alumina-based mother.
  • Pd and Ni are co-supported on the material particles and then fired at 450 ° C. for 0.5 hours to form composite particles in which Pd and Ni are supported on the alumina-based base material particles, and then wet milling.
  • the particles are kneaded until the average particle size D90 is within the range of 14 to 18 ⁇ m to obtain the methane oxidation catalyst of Example 10 (containing 3.6% by mass in terms of Pd and 6.0% by mass in terms of Ni). rice field.
  • the obtained methane oxidation catalyst of Example 10 was wet-coated on a cordierite carrier (manufactured by NGK, ⁇ 25.4 x 50 mm) (coating amount: 125 g / L, Pd equivalent coating amount: 4.5 g / L, Ni-equivalent coating amount: 7.4 g / L))) was fired at 450 ° C. for 30 minutes to obtain the methane oxidation lamination catalyst of Example 10.
  • the alumina-based base particle to be used is an alumina-based base particle (manufactured by Sasol, trade name: TH130 / 130, BET specific surface area: 130 m 2 / g, average particle diameter D50: 22 ⁇ m, pore diameter (peak value): 26.
  • the same procedure as in Example 10 was carried out except that the particle volume was changed to 2 nm and the pore volume: 2.29 cc / g) to obtain the methane oxide lamination catalyst of Example 11.
  • Example 12 to 16 The same procedure as in Example 7 was carried out except that the amount of coating applied during wet coating was changed as shown in Table 2, to obtain methane oxidation laminated catalysts of Examples 12 to 16.
  • the methane oxidation catalyst, the methane oxidation laminated catalyst, and the like of the present invention have enhanced catalytic activity of methane contained in the gas in a low temperature region of less than 500 ° C., compressed natural gas (CNG), liquefied natural gas, etc.
  • CNG compressed natural gas
  • oxidation catalyst for methane contained in gas discharged from (LNG) city gas, light oil, kerosene and other boilers, heating furnaces, gas engines, gas turbines, dilute combustion gas engines, and other internal combustion engines.
  • oxidation catalyst for methane contained in exhaust gas discharged from compression ignition internal combustion engines such as diesel engines, bifuel engines (BF) and dual fuel engines (CNG-DFCI, LNG-DFCI, etc.) using the same. It can be effectively used.
  • compression ignition internal combustion engines such as diesel engines, bifuel engines (BF) and dual fuel engines (CNG-DFCI, LNG-DFCI, etc.) using the same. It can be effectively used.

Abstract

The present invention provides: a novel methane oxidation catalyst which has enhanced methane catalytic activity in a low temperature range of less than 500°C; a methane oxidation multilayer catalyst; an exhaust gas purification system which uses this methane oxidation catalyst or this methane oxidation multilayer catalyst; a method for producing a methane oxidation catalyst; and the like. A methane oxidation catalyst which is used for the purpose of oxidizing methane contained in a gas, and which contains alumina-based base material particles and composite particles that are supported by the alumina-based base material particles, while containing Pd and Ni.

Description

メタン酸化触媒、メタン酸化積層触媒、及びこれらを用いた排ガス浄化システム、並びにメタン酸化触媒の製造方法A methane oxidation catalyst, a methane oxidation laminated catalyst, an exhaust gas purification system using these, and a method for manufacturing a methane oxidation catalyst.
　本発明は、ガス中に含まれるメタンを酸化するためのメタン酸化触媒、メタン酸化積層触媒、及びこれらを用いた排ガス浄化システム、並びにメタン酸化触媒の製造方法等に関する。 The present invention relates to a methane oxidation catalyst for oxidizing methane contained in gas, a methane oxidation laminated catalyst, an exhaust gas purification system using these, a method for producing a methane oxidation catalyst, and the like.
　圧縮天然ガス（ＣＮＧ）、液化天然ガス（ＬＮＧ）、都市ガス、軽油、灯油等を燃料として用いるボイラー、加熱炉、ガスエンジン、ガスタービン等から排出される排ガスは、一酸化炭素（ＣＯ）、一酸化窒素（ＮＯ）、窒素酸化物（ＮＯｘ）、硫黄酸化物（ＳＯｘ）等の他に、少量の未燃焼の炭化水素（ＨＣ）を含み得る。また、コージェネレーションシステムやガスヒートポンプ（ＧＨＰ）等の希薄燃焼ガスエンジンから排出される排ガスについても同様であり、ＣＮＧ又はＬＮＧとガソリン又は軽油とを併用するバイフューエルエンジン（ＢＦ）やデュアルフューエルエンジン（ＣＮＧ－ＤＦＣＩ、ＬＮＧ－ＤＦＣＩ等）から排出される排ガスにおいても同様である。また、軽油等を燃料とする内燃機関、例えばディーゼルエンジン等から排出される排ガスについても微量のメタンを含む場合がある。 Exhaust emissions from boilers, heating furnaces, gas engines, gas turbines, etc. that use compressed natural gas (CNG), liquefied natural gas (LNG), city gas, light oil, kerosene, etc. as fuel are carbon monoxide (CO), In addition to nitrogen monoxide (NO), nitrogen oxides (NOx), sulfur oxides (SOx) and the like, it may contain small amounts of unburned hydrocarbons (HC). The same applies to the exhaust gas emitted from a lean combustion gas engine such as a cogeneration system or a gas heat pump (GHP), and a bi-fuel engine (BF) or a dual fuel engine (BF) or a dual fuel engine in which CNG or LNG is used in combination with gasoline or light oil ( The same applies to the exhaust gas emitted from CNG-DFCI, LNG-DFCI, etc.). Further, the exhaust gas emitted from an internal combustion engine using light oil or the like as a fuel, for example, a diesel engine or the like may also contain a trace amount of methane.
　これらの各成分は、環境汚染の原因となるため、浄化処理して排出する必要がある。しかしながら、排ガス中に含まれ得る炭化水素の中でも、とりわけメタンは、化学的安定性が比較的に高いため、十分な浄化率（メタン除去率）が得られ難いという側面がある。この傾向は、希薄燃焼ガスエンジンのような希薄燃焼方式の場合に、その排ガス中に過剰の酸素が存在するため、さらには、多量のＮＯｘや水蒸気が共存するため、より顕在化する。 Each of these components causes environmental pollution, so it is necessary to purify and discharge them. However, among the hydrocarbons that can be contained in the exhaust gas, methane in particular has a relatively high chemical stability, so that it is difficult to obtain a sufficient purification rate (methane removal rate). This tendency becomes more apparent in the case of a lean burn system such as a lean burn gas engine because excess oxygen is present in the exhaust gas and a large amount of NOx and water vapor coexist.
　従来、炭化水素の酸化触媒としては、触媒活性成分として白金、パラジウム、ロジウム等の白金族元素（ＰＧＭ：Platinum Group Metal）をアルミア系母材粒子上に担持した、例えばＰｄ担持アルミナやＰｔ／Ｐｄ担持アルミナ等が知られている（例えば、特許文献１～３参照）。 Conventionally, as an oxidation catalyst for hydrocarbons, platinum group elements (PGM: Platinum Group Metal) such as platinum, palladium, and rhodium are supported on aluminum base material particles as catalytically active components, for example, Pd-supported alumina and Pt / Pd. Supported alumina and the like are known (see, for example, Patent Documents 1 to 3).
　また、低温域でのメタン酸化活性や高湿耐久性等を高めるために、これらのＰｄ担持アルミナやＰｔ／Ｐｄ担持アルミナ等とともに、ＳｉＯ２、ＴｉＯ２、ＭｇＯ，ＣａＯ，ＺｒＯ２超等の高疎水性酸化物やＭｇＯ、ＭｇＡｌ２Ｏ４、ＣｅＯ２、Ｙ２Ｏ３、Ｎｄ２Ｏ３、ＺｒＯ２等の固体塩基性が高い酸化物を併用する試み（例えば、特許文献４参照）、ＳｎＯ２を併用する試み（例えば、特許文献５参照）がなされている。 In addition, in order to enhance methane oxidation activity and high humidity durability in the low temperature range, along with these Pd-supported alumina, Pt / Pd-supported alumina, etc., the height of SiO 2 , TiO 2 , MgO, CaO, ZrO 2 , etc. is high. Attempt to use hydrophobic oxides and oxides with high solid basicity such as MgO, MgAl 2 O 4 , CeO 2 , Y 2 O 3 , Nd 2 O 3 , ZrO 2 (see, for example, Patent Document 4), SnO Attempts have been made to use 2 in combination (see, for example, Patent Document 5).
米国特許第５１３１２２４号U.S. Pat. No. 5,131,224 米国特許第５２１６８７５号U.S. Pat. No. 5,216,875 米国特許第５３８４３００号U.S. Pat. No. 5,384,300 特開２００３－０７１２８８号公報Japanese Patent Application Laid-Open No. 2003-071288 特表２００６－５２１２０３号公報Special Table 2006-521203 Publication No.
　しかしながら、特許文献１～３に記載の触媒は、例えば５００℃以上の高温領域において作用し、５００℃未満の低温領域での触媒活性が低いという問題があり、かかる低温領域におけるメタンの酸化活性の向上が求められている。 However, the catalysts described in Patent Documents 1 to 3 have a problem that they act in a high temperature region of, for example, 500 ° C. or higher and have low catalytic activity in a low temperature region of less than 500 ° C., and the oxidative activity of methane in such a low temperature region is high. Improvement is required.
　一方、特許文献４に記載の触媒は、特許文献１～３の触媒に対して低温領域におけるメタンの酸化活性の向上は認められるもの、その向上程度は十分ではなく、未だ改善余地がある。また、特許文献５に記載の触媒は、有機化合物やアッシュ等との化学的作用により生体毒となり得るスズを使用しているため、製造時や使用時の安全性や環境への影響等の観点から、代替品の開発が求められる。 On the other hand, the catalyst described in Patent Document 4 is found to have improved methane oxidation activity in the low temperature region as compared with the catalysts of Patent Documents 1 to 3, but the degree of improvement is not sufficient and there is still room for improvement. Further, since the catalyst described in Patent Document 5 uses tin, which can be a biological poison due to chemical action with organic compounds, ash, etc., from the viewpoint of safety during manufacturing and use, impact on the environment, etc. Therefore, the development of alternative products is required.
　本発明は、上記課題に鑑みてなされたものである。その目的は、５００℃未満の低温領域でのメタン触媒活性が高められた、新規なメタン酸化触媒、メタン酸化積層触媒、及びこれらを用いた排ガス浄化システム、並びにメタン酸化触媒の製造方法等を提供することにある。 The present invention has been made in view of the above problems. The purpose is to provide a novel methane oxidation catalyst, a methane oxidation laminated catalyst, an exhaust gas purification system using these, a method for producing a methane oxidation catalyst, etc., in which the methane catalyst activity is enhanced in a low temperature region of less than 500 ° C. To do.
　本発明者らは、上記課題を解決すべく鋭意検討した。その結果、アルミナ系母材粒子上にＰｄ及びＮｉが担持された複合触媒を用いることで、上記課題を解決できることを見出し、本発明を完成するに至った。 The present inventors have diligently studied to solve the above problems. As a result, they have found that the above problems can be solved by using a composite catalyst in which Pd and Ni are supported on alumina-based base material particles, and have completed the present invention.
　すなわち、本発明は、以下に示す種々の具体的態様を提供する。
［１］ガス中に含まれるメタンを酸化するためのメタン酸化触媒であり、アルミナ系母材粒子、及び前記アルミナ系母材粒子上に担持されたＰｄとＮｉとを含有する複合粒子を含む、メタン酸化触媒。 That is, the present invention provides various specific embodiments shown below.
[1] A methane oxidation catalyst for oxidizing methane contained in a gas, which comprises alumina-based base material particles and composite particles containing Pd and Ni supported on the alumina-based base material particles. Methane oxidation catalyst.
［２］前記アルミナ系母材粒子が、５ｎｍ以上３０ｎｍ以下の細孔径を有する［１］に記載のメタン酸化触媒。 [2] The methane oxidation catalyst according to [1], wherein the alumina-based base material particles have a pore diameter of 5 nm or more and 30 nm or less.
［３］前記アルミナ系母材粒子が、５μｍ以上２００μｍ以下の平均粒子径Ｄ５０を有する［１］又は［２］に記載のメタン酸化触媒。 [3] The methane oxidation catalyst according to [1] or [2], wherein the alumina-based base material particles have an average particle diameter D50 of 5 μm or more and 200 μm or less.
［４］ＰｄとＮｉの含有モル比（Ｐｄ／Ｎｉ）が、１／１～１／３である［１］～［３］のいずれか一項に記載のメタン酸化触媒。 [4] The methane oxidation catalyst according to any one of [1] to [3], wherein the molar ratio of Pd to Ni (Pd / Ni) is 1/1 to 1/3.
［５］Ｐｄ及びＮｉの含有量が、前記複合粒子の総量に対する金属換算量で、それぞれ３～２０質量％である［１］～［４］のいずれか一項に記載のメタン酸化触媒。 [5] The methane oxidation catalyst according to any one of [1] to [4], wherein the contents of Pd and Ni are 3 to 20% by mass, respectively, in terms of metal with respect to the total amount of the composite particles.
［６］前記アルミナ系母材粒子が、α－アルミナ、γ－アルミナ、及びベーマイトよりなる群から選択される１種以上を含む［１］～［５］のいずれか一項に記載のメタン酸化触媒。 [6] The methane oxidation according to any one of [1] to [5], wherein the alumina-based base material particles include at least one selected from the group consisting of α-alumina, γ-alumina, and boehmite. catalyst.
［７］前記アルミナ系母材粒子が、アルカリ金属元素、アルカリ土類金属元素、遷移元素、及び希土類元素よりなる群から選択される１種以上を含む［１］～［６］のいずれか一項に記載のメタン酸化触媒。 [7] Any one of [1] to [6], wherein the alumina-based base metal particles include at least one selected from the group consisting of alkali metal elements, alkaline earth metal elements, transition elements, and rare earth elements. The methane oxidation catalyst described in the section.
［８］前記アルミナ系母材粒子が、１．５ｃｃ／ｇ以上２．５ｃｃ／ｇ以下の細孔容積を有する［１］～［７］のいずれか一項に記載のメタン酸化触媒。 [8] The methane oxidation catalyst according to any one of [1] to [7], wherein the alumina-based base material particles have a pore volume of 1.5 cc / g or more and 2.5 cc / g or less.
［９］前記ガスが、内燃機関から排出される排ガスであ［１］～［８］のいずれか一項に記載のメタン酸化触媒。 [9] The methane oxidation catalyst according to any one of [1] to [8], wherein the gas is an exhaust gas discharged from an internal combustion engine.
［１０］前記ガスが、メタンを燃料として使用する内燃機関から排出される排ガスである［１］～［９］のいずれか一項に記載のメタン酸化触媒。 [10] The methane oxidation catalyst according to any one of [1] to [9], wherein the gas is an exhaust gas discharged from an internal combustion engine using methane as a fuel.
［１１］ガス中に含まれるメタンを酸化するためのメタン酸化積層触媒であり、触媒担体、並びに、前記触媒担体上に支持された触媒層を備え、前記触媒層は、アルミナ系母材粒子、及び前記アルミナ系母材粒子に担持されたＰｄとＮｉとを含有する複合粒子を含むメタン酸化触媒を有する、メタン酸化積層触媒。ここで、このメタン酸化積層触媒は、上記［１］～［１０］のいずれか一項に記載の技術的特徴をさらに有することが好ましい。 [11] A methane oxidation laminated catalyst for oxidizing methane contained in a gas, comprising a catalyst carrier and a catalyst layer supported on the catalyst carrier, wherein the catalyst layer is an alumina-based base metal particle. A methane oxidation laminated catalyst comprising a methane oxidation catalyst containing composite particles containing Pd and Ni supported on the alumina-based base metal particles. Here, it is preferable that the methane oxidation laminated catalyst further has the technical features described in any one of the above [1] to [10].
［１２］前記触媒層の塗工量が、前記触媒担体１Ｌに対して、１００ｇ／Ｌ以上２００ｇ／Ｌ以下である［１１］に記載のメタン酸化積層触媒。 [12] The methane oxidation laminated catalyst according to [11], wherein the coating amount of the catalyst layer is 100 g / L or more and 200 g / L or less with respect to 1 L of the catalyst carrier.
［１３］Ｐｄの塗工量が、前記触媒担体１Ｌに対して、４．５ｇ／Ｌ以上１６．０ｇ／Ｌ以下である［１１］又は［１２］に記載のメタン酸化積層触媒。 [13] The methane oxidation laminated catalyst according to [11] or [12], wherein the coating amount of Pd is 4.5 g / L or more and 16.0 g / L or less with respect to 1 L of the catalyst carrier.
［１４］Ｎｉの塗工量が、前記触媒担体１Ｌに対して、１．０ｇ／Ｌ以上１１．０ｇ／Ｌ以下である［１１］～［１３］のいずれか一項に記載のメタン酸化積層触媒。 [14] The methane oxidation lamination according to any one of [11] to [13], wherein the coating amount of Ni is 1.0 g / L or more and 11.0 g / L or less with respect to 1 L of the catalyst carrier. catalyst.
［１５］内燃機関から排出される排ガスの排ガス流路に、アルミナ系母材粒子、及び前記アルミナ系母材粒子に担持されたＰｄとＮｉとを含有する複合粒子を含むメタン酸化触媒が配置された、排ガス浄化システム。ここで、この排ガス浄化システムは、上記［１］～［１４］のいずれか一項に記載の技術的特徴をさらに有することが好ましい。 [15] A methane oxidation catalyst containing alumina-based base material particles and composite particles containing Pd and Ni supported on the alumina-based base material particles is arranged in the exhaust gas flow path of the exhaust gas discharged from the internal combustion engine. Also, an exhaust gas purification system. Here, it is preferable that this exhaust gas purification system further has the technical features described in any one of the above [1] to [14].
［１６］アルミナ系母材粒子を、Ｐｄ塩及びＮｉ塩を含む溶液に浸漬し、前記アルミナ系母材粒子上にＰｄとＮｉとを共担持させ、前記アルミナ系母材粒子上にＰｄ及びＮｉが担持された複合粒子を形成する、メタン酸化触媒の製造方法。ここで、このメタン酸化触媒の製造方法は、上記［１］～［１０］のいずれか一項に記載の技術的特徴をさらに有することが好ましい。 [16] Alumina-based base material particles are immersed in a solution containing Pd salt and Ni salt, Pd and Ni are co-supported on the alumina-based base material particles, and Pd and Ni are placed on the alumina-based base material particles. A method for producing a methane oxidation catalyst, which forms composite particles on which the particles are supported. Here, it is preferable that the method for producing the methane oxidation catalyst further has the technical features described in any one of the above [1] to [10].
　本発明によれば、５００℃未満の低温領域でのメタン触媒活性が高められた、新規なメタン酸化触媒、メタン酸化積層触媒、及びこれらを用いた排ガス浄化システム、並びにメタン酸化触媒の製造方法等を実現することができる。 According to the present invention, a novel methane oxidation catalyst having enhanced methane catalytic activity in a low temperature region of less than 500 ° C., a methane oxidation laminated catalyst, an exhaust gas purification system using these, a method for producing a methane oxidation catalyst, etc. Can be realized.
一実施形態のメタン酸化触媒の概略構成を示す模式図である。It is a schematic diagram which shows the schematic structure of the methane oxidation catalyst of one Embodiment. 実施例１及び比較例１～３のメタン酸化除去性能の温度依存性を示すグラフである。It is a graph which shows the temperature dependence of the methane oxidation removal performance of Example 1 and Comparative Examples 1 to 3. 実施例１及び比較例４～８のメタン酸化除去性能を示すグラフである。It is a graph which shows the methane oxidation removal performance of Example 1 and Comparative Examples 4-8. 実施例１及び比較例９～１２のメタン酸化除去性能を示すグラフである。It is a graph which shows the methane oxidation removal performance of Example 1 and Comparative Examples 9-12. 実施例２～５のメタン酸化除去性能を示すグラフである。It is a graph which shows the methane oxidation removal performance of Examples 2-5. 実施例２～５のメタン酸化除去性能を示すグラフである。It is a graph which shows the methane oxidation removal performance of Examples 2-5. 実施例６～９のメタン酸化除去性能を示すグラフである。It is a graph which shows the methane oxidation removal performance of Examples 6-9. 実施例６～９のメタン酸化除去性能を示すグラフである。It is a graph which shows the methane oxidation removal performance of Examples 6-9. 実施例２，６及び７、並びに比較例１のアルミニウム系母材粒子上のＰｄ粒子の粒子径を示すグラフである。6 is a graph showing the particle diameters of Pd particles on the aluminum-based base material particles of Examples 2, 6 and 7, and Comparative Example 1. 実施例１０～１１のメタン酸化除去性能を示すグラフである。It is a graph which shows the methane oxidation removal performance of Examples 10-11. 実施例７，１２～１６のメタン酸化除去性能を示すグラフである。It is a graph which shows the methane oxidation removal performance of Examples 7, 12 to 16.
　以下、本発明の実施の形態について詳細に説明する。以下の実施の形態は、本発明の実施態様の一例（代表例）であり、本発明はこれらに限定されるものではない。また、本発明は、その要旨を逸脱しない範囲内で任意に変更して実施することができる。なお、本明細書において、「～」を用いてその前後に数値又は物性値を挟んで表現する場合、その前後の値を含むものとして用いる。例えば「１～１００」との数値範囲の表記は、その下限値「１」及び上限値「１００」の双方を包含するものとする。また、他の数値範囲の表記も同様である。 Hereinafter, embodiments of the present invention will be described in detail. The following embodiments are examples (representative examples) of embodiments of the present invention, and the present invention is not limited thereto. Further, the present invention can be arbitrarily modified and implemented without departing from the gist thereof. In addition, in this specification, when a numerical value or a physical property value is put before and after using "-", it is used as including the value before and after that. For example, the notation of the numerical range of "1 to 100" includes both the lower limit value "1" and the upper limit value "100". The same applies to the notation of other numerical ranges.
　本実施形態のメタン酸化触媒１００は、ガス中に含まれるメタンを酸化するための酸化触媒であり、アルミナ系母材粒子１１、及びこのアルミナ系母材粒子１１の表面１１ａ上に担持されたＰｄとＮｉとを含有する複合粒子２１を含むことを特徴とする。 The methane oxidation catalyst 100 of the present embodiment is an oxidation catalyst for oxidizing methane contained in the gas, and is a Pd supported on the alumina-based base material particles 11 and the surface 11a of the alumina-based base material particles 11. It is characterized by containing composite particles 21 containing Ni and Ni.
　アルミナ系母材粒子１１は、アルミナを構成成分とする粒子であり、その表面１１ａ上にＰｄやＮｉを担持させる担体粒子である。ここで、本明細書において、アルミナとは、α－アルミナ、γ－アルミナ、δ－アルミナ、θ－アルミナ等の酸化アルミニウムの他、ベーマイト［α－ＡｌＯ（ＯＨ）］やダイアスポア［β－ＡｌＯ（ＯＨ）］等の水酸化酸化アルミニウム又はアルミナ水和物Ａｌ２Ｏ３・ｎ（Ｈ２Ｏ））等を包含する概念である。なお、アルミナは、１種を単独で、又は２種以上を任意の組み合わせ及び比率で用いることができる。これらの中でも、アルミナとしては、α－アルミナ、γ－アルミナ、ベーマイトが好ましい。また、耐久性を向上させる等の観点から、カリウム、ナトリウム等のアルカリ金属元素、バリウム、マグネシウム等のアルカリ土類金属元素、鉄、コバルト、チタン等の遷移元素、セリウム、ランタン、ネオジム、ジルコニウム、プラセオジム等の希土類元素等の他の成分を含有していてもよい。ただし、これらの含有量は、アルミナ系母材粒子１１の高いＢＥＴ比表面積を維持する観点から３０質量％以下が好ましい。なお、アルミナ中に含まれてもよい他の成分は、１種を単独で、又は２種以上を任意の組み合わせ及び比率で用いることができる。また、アルミナ系母材粒子１１の粒子形状は、特に限定されず、例えば球状、楕円体状、破砕状、扁平形状、不定形状等いずれであっても構わない。 The alumina-based base material particles 11 are particles containing alumina as a constituent component, and are carrier particles that support Pd and Ni on the surface 11a thereof. Here, in the present specification, alumina means aluminum oxide such as α-alumina, γ-alumina, δ-alumina, and θ-alumina, as well as boehmite [α-AlO (OH)] and diaspoa [β-AlO (β-AlO). OH)] and the like are aluminum oxide hydroxides or alumina hydrates Al 2 O 3 · n (H 2 O)) and the like. As for alumina, one type can be used alone, or two or more types can be used in any combination and ratio. Among these, as the alumina, α-alumina, γ-alumina, and boehmite are preferable. From the viewpoint of improving durability, alkali metal elements such as potassium and sodium, alkaline earth metal elements such as barium and magnesium, transition elements such as iron, cobalt and titanium, cerium, lanthanum, neodymium and zirconium, It may contain other components such as rare earth elements such as praseodymium. However, these contents are preferably 30% by mass or less from the viewpoint of maintaining a high BET specific surface area of the alumina-based base material particles 11. As for other components that may be contained in alumina, one kind may be used alone, or two or more kinds may be used in any combination and ratio. The particle shape of the alumina-based base material particles 11 is not particularly limited, and may be, for example, spherical, ellipsoidal, crushed, flat, indefinite, or the like.
　アルミナ系母材粒子１１の平均粒子径（Ｄ５０）は、所望性能に応じて適宜設定でき、特に限定されないが、大きな比表面積を保持させるとともに耐熱性を高めて自身の触媒活性サイトの数を増大させる等の観点から、５～２００μｍであることが好ましく、より好ましくは１０～１５０μｍ、さらに好ましくは１５～１００μｍである。なお、本明細書において、平均粒子径Ｄ５０は、レーザ回折式粒度分布測定装置（例えば、島津製作所社製、レーザ回折式粒度分布測定装置ＳＡＬＤ－７１００等）で測定されるメディアン径を意味する。 The average particle diameter (D50) of the alumina-based base material particles 11 can be appropriately set according to the desired performance, and is not particularly limited, but maintains a large specific surface area and enhances heat resistance to increase the number of its own catalytically active sites. From the viewpoint of allowing the particles to grow, the thickness is preferably 5 to 200 μm, more preferably 10 to 150 μm, and even more preferably 15 to 100 μm. In the present specification, the average particle size D50 means a median diameter measured by a laser diffraction type particle size distribution measuring device (for example, a laser diffraction type particle size distribution measuring device SALD-7100 manufactured by Shimadzu Corporation).
　ここで用いるアルミナ系母材粒子１１の細孔径は、所望性能に応じて適宜設定でき、特に限定されないが、５００℃未満の低温領域でのメタンの触媒活性を向上させる観点から、５ｎｍ以上３０ｎｍ以下が好ましく、より好ましくは７ｎｍ以上２９ｎｍ以下、さらに好ましくは１０ｎｍ以上２８ｎｍ以下である。なお、アルミナ系母材粒子１１の細孔径は、水銀圧入法により算出される値を意味する。ここでは、後述する実施例に記載の条件下にて細孔容積を測定し、このとき得られる細孔径－微分細孔容量の細孔分布曲線におけるピークトップ位置の値を、アルミナ系母材粒子１１の細孔径とする。 The pore diameter of the alumina-based base material particles 11 used here can be appropriately set according to the desired performance and is not particularly limited, but is 5 nm or more and 30 nm or less from the viewpoint of improving the catalytic activity of methane in a low temperature region of less than 500 ° C. Is more preferable, and more preferably 7 nm or more and 29 nm or less, and further preferably 10 nm or more and 28 nm or less. The pore diameter of the alumina-based base material particles 11 means a value calculated by the mercury intrusion method. Here, the pore volume is measured under the conditions described in Examples described later, and the value of the peak top position in the pore distribution curve of the pore diameter-differential pore volume obtained at this time is set as the alumina-based base material particles. The pore diameter is 11.
　なお、アルミナ系母材粒子１１の細孔容積が大きいほど、一般的にはメタンの触媒活性が高くなる傾向にある。そのため、アルミナ系母材粒子１１の細孔容積は、所望性能に応じて適宜設定でき、特に限定されないが、１．０ｃｃ／ｇ以上３．０ｃｃ／ｇ以下が好ましく、より好ましくは１．２ｃｃ／ｇ以上２．８ｃｃ／ｇ以下、さらに好ましくは１．５ｃｃ／ｇ以上２．５ｃｃ／ｇ以下である。なお、アルミナ系母材粒子１１の細孔容積は、水銀圧入法により算出される値を意味する。ここでは、後述する実施例に記載の条件下にて細孔容積を測定する。 It should be noted that the larger the pore volume of the alumina-based base material particles 11, the higher the catalytic activity of methane generally tends to be. Therefore, the pore volume of the alumina-based base material particles 11 can be appropriately set according to the desired performance and is not particularly limited, but is preferably 1.0 cc / g or more and 3.0 cc / g or less, and more preferably 1.2 cc / g. It is g or more and 2.8 cc / g or less, more preferably 1.5 cc / g or more and 2.5 cc / g or less. The pore volume of the alumina-based base material particles 11 means a value calculated by the mercury intrusion method. Here, the pore volume is measured under the conditions described in Examples described later.
　上述したアルミナ系母材粒子１１の表面１１ａには、触媒活性成分としてＰｄ及びＮｉが担持されている。このようにＰｄのみならずＮｉを表面１１ａに担持させることで、５００℃未満の低温領域でのメタンの触媒活性を飛躍的に向上させることができる。なお、アルミナ系母材粒子１１の表面１１ａ上のＰｄ及びＮｉは、外部環境に応じて、金属単体や酸化物等に変化し得るものである。したがって、ＰｄやＮｉの酸化状態は特に限定されないが、還元性雰囲気下において、粒子であることが好ましい。 Pd and Ni are supported as catalytically active components on the surface 11a of the above-mentioned alumina-based base material particles 11. By supporting not only Pd but also Ni on the surface 11a in this way, the catalytic activity of methane in a low temperature region of less than 500 ° C. can be dramatically improved. The Pd and Ni on the surface 11a of the alumina-based base material particles 11 can change to a simple substance of a metal, an oxide, or the like depending on the external environment. Therefore, the oxidation state of Pd and Ni is not particularly limited, but it is preferably particles in a reducing atmosphere.
　複合粒子２１に含まれるＰｄ及びＮｉの含有モル比（Ｐｄ／Ｎｉ）は、所望性能に応じて適宜設定でき、特に限定されないが、０．２５／１～１／５が好ましく、より好ましくは０．５／１～１／４、さらに好ましくは１／１～１／３である。Ｎｉの含有割合が高いほど、アルミナ系母材粒子１１の表面１１ａに担持されるＰｄの平均粒子径（Ｄ５０）が小さくなる傾向にあり、５００℃未満の低温領域でのメタンの触媒活性が高くなる傾向にある。 The molar ratio (Pd / Ni) of Pd and Ni contained in the composite particle 21 can be appropriately set according to the desired performance and is not particularly limited, but is preferably 0.25/1 to 1/5, more preferably 0. .5 / 1 to 1/4, more preferably 1/1 to 1/3. The higher the Ni content ratio, the smaller the average particle diameter (D50) of Pd supported on the surface 11a of the alumina-based base material particles 11, and the higher the catalytic activity of methane in the low temperature region below 500 ° C. It tends to be.
　アルミナ系母材粒子１１上に担持されるＰｄやＮｉの含有量は、所望性能に応じて適宜決定でき、特に限定されないが、５００℃未満の低温触媒活性を向上させる等の観点から、複合粒子２１の総量に対する金属換算量で、それぞれ３～２０質量％が好ましく、より好ましくはそれぞれ４～１７質量％であり、さらに好ましくはそれぞれ５～１５質量％である。 The content of Pd and Ni supported on the alumina-based base material particles 11 can be appropriately determined according to the desired performance and is not particularly limited, but is not particularly limited, but is a composite particle from the viewpoint of improving the low temperature catalytic activity below 500 ° C. The metal equivalent amount with respect to the total amount of 21 is preferably 3 to 20% by mass, more preferably 4 to 17% by mass, and further preferably 5 to 15% by mass, respectively.
　アルミナ系母材粒子１１の表面１１ａ上のＰｄの平均粒子径（Ｄ５０）は、０．５ｎｍ以上３．０ｎｍ以下が好ましく、より好ましくは０．７ｎｍ以上２．５ｎｍ以下、さらに好ましくは０．９ｎｍ以上２．０ｎｍ以下である。このように微細なＰｄが表面１１ａ上に高分散に担持された複合粒子２１とすることで、５００℃未満の低温領域でのメタンの触媒活性が高くなる傾向にある。 The average particle diameter (D50) of Pd on the surface 11a of the alumina-based base material particles 11 is preferably 0.5 nm or more and 3.0 nm or less, more preferably 0.7 nm or more and 2.5 nm or less, and further preferably 0.9 nm. It is 2.0 nm or less. By forming the composite particles 21 in which fine Pd is supported on the surface 11a in a highly dispersed manner, the catalytic activity of methane in a low temperature region of less than 500 ° C. tends to be high.
　ここで、触媒性能の低下ないし劣化を避ける観点から、複合粒子２１は、水銀、鉛、スズ、亜鉛、及びこれらの酸化物を実質的に含有しないことが好ましい。これらは、有機化合物やアッシュ等との化学的作用により生体毒となり得る。そのため、水銀、鉛、スズ、亜鉛、及びこれらの酸化物の含有割合は、複合粒子２１の総量に対する金属換算量で、１０質量％未満が好ましく、より好ましくは３質量％未満、さらに好ましくは１質量％未満、特に好ましくは０．５質量％未満、最も好ましくは０．１質量％未満である。 Here, from the viewpoint of avoiding deterioration or deterioration of the catalytic performance, it is preferable that the composite particles 21 do not substantially contain mercury, lead, tin, zinc, and oxides thereof. These can be biotoxic due to chemical action with organic compounds, ash and the like. Therefore, the content ratio of mercury, lead, tin, zinc, and their oxides is preferably less than 10% by mass, more preferably less than 3% by mass, still more preferably 1 in terms of metal equivalent to the total amount of the composite particles 21. It is less than mass%, particularly preferably less than 0.5% by mass, and most preferably less than 0.1% by mass.
　なお、本実施形態のメタン酸化触媒１００は、上述した複合粒子２１を含むものである限り、他の成分を含有していてもよい。他の成分としては、例えば、Ｐｄ及びＮｉ以外の触媒活性成分（以降において、単に「他の触媒活性成分」という場合がある。）、上述したアルミナ系母材粒子１１以外の母材粒子（以降において、単に「他の母材粒子」という場合がある。）等が挙げられる。他の触媒活性成分としては、Ｐｄ以外の白金族元素、具体的にはプラチナ（Ｐｔ）、ロジウム（Ｒｈ）、イリジウム（Ｉｒ）、ルテニウム（Ｒｕ）、オスミウム（Ｏｓ）が挙げられる。なお、白金族元素は、それぞれ１種を単独で、又は２種以上の任意の組み合わせ及び割合で用いることができる。また、他の母材粒子としては、Ｐｄ及び／又はＮｉが担持されていないアルミナ系粒子、セリアやジルコニア等の金属酸化物；希土類元素及び／又は遷移元素がドープされたジルコニアやセリア－ジルコニア等の複合酸化物；ペロブスカイト型酸化物；ゼオライト；シリカ－アルミナ、シリカ－アルミナ－ジルコニア、シリカ－アルミナ－ボリア等のアルミナを含む複合酸化物；等が挙げられる。これらの他の触媒活性成分や他の母材粒子の使用割合は、特に限定されないが、メタン酸化触媒１００の総量に対して、合計で０．０１～３０質量％が好ましく、より好ましくは合計で０．０１～１５質量％、さらに好ましく合計で０．０１～５質量％である。 The methane oxidation catalyst 100 of the present embodiment may contain other components as long as it contains the above-mentioned composite particles 21. Examples of the other components include catalytically active components other than Pd and Ni (hereinafter, may be simply referred to as “other catalytically active components”), and base material particles other than the above-mentioned alumina-based base material particles 11. In the above, it may be simply referred to as "other base material particles") and the like. Examples of other catalytically active components include platinum group elements other than Pd, specifically platinum (Pt), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os). As the platinum group elements, one type may be used alone, or two or more types may be used in any combination and ratio. Other base material particles include alumina-based particles in which Pd and / or Ni are not supported, metal oxides such as ceria and zirconia; zirconia and ceria-zirconia doped with rare earth elements and / or transition elements, and the like. Composite oxides; perovskite-type oxides; zeolites; composite oxides containing alumina such as silica-alumina, silica-alumina-zirconia, and silica-alumina-boria; and the like. The proportion of these other catalytically active components and other base metal particles used is not particularly limited, but is preferably 0.01 to 30% by mass in total, and more preferably in total, with respect to the total amount of the methane oxidation catalyst 100. It is 0.01 to 15% by mass, more preferably 0.01 to 5% by mass in total.
　また、本実施形態のメタン酸化触媒１００は、上述した複合粒子２１や他の成分の他に、当業界で公知の添加剤を含んでいてもよい。添加剤としては、各種バインダー、非イオン系界面活性剤やアニオン系界面活性剤等の分散安定化剤、ｐＨ調整剤、粘度調整剤等が挙げられるが、これらに特に限定されない。これらの添加剤の使用割合は、特に限定されないが、メタン酸化触媒１００の総量に対して、合計で０．０１～１０質量％が好ましく、合計で０．０５～８質量％がより好ましく、合計で０．１～５質量％がさらに好ましい。 Further, the methane oxidation catalyst 100 of the present embodiment may contain additives known in the art in addition to the above-mentioned composite particles 21 and other components. Examples of the additive include, but are not limited to, various binders, dispersion stabilizers such as nonionic surfactants and anionic surfactants, pH adjusters, viscosity adjusters and the like. The proportion of these additives used is not particularly limited, but is preferably 0.01 to 10% by mass in total, more preferably 0.05 to 8% by mass in total, and total to the total amount of the methane oxidation catalyst 100. It is more preferably 0.1 to 5% by mass.
　上述した複合粒子２１は、常法にしたがって製造することができ、その製造方法は、特に限定されない。再現性よく簡易且つ低コストで製造する観点からは、蒸発乾固法（含浸法、スプレードライ法等）等が好ましい。例えば、アルミナ系母材粒子１１（以降において、「原料アルミナ粉体」と称する場合がある。）を、Ｐｄ塩を含む溶液に浸漬し、アルミナ系母材粒子１１の表面１１ａ上にＰｄを担持させ、その後さらにＮｉ塩を含む溶液に浸漬し、アルミナ系母材粒子１１の表面１１ａ上にＮｉを担持させることで、複合粒子２１を得ることができる。この含浸処理により、Ｐｄイオン及び／又はＮｉイオンが、アルミナ系母材粒子１１の表面１１ａに高分散状態で吸着（付着）される。このとき、ＰｄとＮｉの担持する順序を逆にすることもできる。好ましい一態様としては、アルミナ系母材粒子１１の表面１１ａ上に微細なＰｄを高分散に担持させる観点から、アルミナ系母材粒子１１を、Ｐｄ塩及びＮｉ塩を含む溶液に浸漬し、アルミナ系母材粒子１１の表面１１ａ上にＰｄとＮｉとを共担持させる方法が挙げられる。 The above-mentioned composite particles 21 can be produced according to a conventional method, and the production method thereof is not particularly limited. From the viewpoint of reproducibility, simplicity, and low cost, the evaporation-drying method (impregnation method, spray-drying method, etc.) is preferable. For example, the alumina-based base material particles 11 (hereinafter, may be referred to as “raw material alumina powder”) is immersed in a solution containing a Pd salt, and Pd is supported on the surface 11a of the alumina-based base material particles 11. Then, the composite particles 21 can be obtained by further immersing the particles in a solution containing a Ni salt and supporting Ni on the surface 11a of the alumina-based base material particles 11. By this impregnation treatment, Pd ions and / or Ni ions are adsorbed (adhered) to the surface 11a of the alumina-based base material particles 11 in a highly dispersed state. At this time, the order in which Pd and Ni are supported can be reversed. As a preferred embodiment, from the viewpoint of supporting fine Pd on the surface 11a of the alumina-based base material particles 11 in a highly dispersed manner, the alumina-based base material particles 11 are immersed in a solution containing a Pd salt and a Ni salt, and alumina is used. A method of co-supporting Pd and Ni on the surface 11a of the system base material particles 11 can be mentioned.
　原料アルミナ粉体のＢＥＴ比表面積は、特に限定されないが、ＰｄやＮｉの高分散担持やガス拡散性等に応じて適宜設定でき、特に限定されないが、１０～４００ｍ２／ｇが好ましく、より好ましくは２０～３５０ｍ２／ｇ、さらに好ましくは５０～３００ｍ２／ｇである。なお、アルミナ粉体として、各種グレードのものが国内外のメーカから数多く市販されており、各種グレードの市販品を、本実施形態のアルミナ系母材粒子１１（原料アルミナ粉体）として用いることができる。また、上述したアルミナ系母材粒子１１（原料アルミナ粉体）は、当業界で公知の方法で製造することもできる。 The BET specific surface area of the raw material alumina powder is not particularly limited, but can be appropriately set depending on the high dispersion support of Pd and Ni, gas diffusivity, etc., and is not particularly limited, but is preferably 10 to 400 m 2 / g, more preferably. Is 20 to 350 m 2 / g, more preferably 50 to 300 m 2 / g. As the alumina powder, many grades are commercially available from domestic and overseas manufacturers, and the commercially available products of various grades can be used as the alumina-based base material particles 11 (raw material alumina powder) of the present embodiment. can. Further, the above-mentioned alumina-based base material particles 11 (raw material alumina powder) can also be produced by a method known in the art.
　Ｐｄ塩及び／又はＮｉ塩を含む溶液は、特に限定されないが、Ｐｄ塩及び／又はＮｉ塩、並びに必要に応じて配合する他の成分や添加剤等を水と混合した、Ｐｄ塩及び／又はＮｉ塩含有水溶液が好適に用いられる。ここで用いる塩の形態は、常法にしたがって選択すればよく、特に限定されないが、一般的には、塩酸塩、オキシ塩酸塩、硝酸塩、オキシ硝酸塩、炭酸塩、リン酸塩、酢酸塩、シュウ酸塩、クエン酸塩、アンミン錯塩等が好ましい。また、水溶液中のＰｄイオン及び／又はＮｉイオンの含有割合は、得られるメタン酸化触媒１００においてＰｄ及びＮｉが所望の含有割合となるように適宜調整することができ、特に限定されない。このような溶液に、例えば上述したアルミナ系母材粒子１１（原料アルミナ粉体）を含浸ないしは浸漬させ、溶媒（例えば水）を除去し、必要に応じて乾燥処理及び／又は２００～６００℃程度の熱処理（焼成処理）を施すことで、アルミナ系母材粒子１１の表面１１ａ上に担持されたＰｄとＮｉとを含有する複合粒子２１を生産性よく得ることができる。 The solution containing the Pd salt and / or the Ni salt is not particularly limited, but the Pd salt and / or the Ni salt and other components and additives to be blended as necessary are mixed with water, and the Pd salt and / or A Ni salt-containing aqueous solution is preferably used. The form of the salt used here may be selected according to a conventional method and is not particularly limited, but is generally limited to hydrochloride, oxyhydrochloride, nitrate, oxynitrate, carbonate, phosphate, acetate and shu. Acidates, citrates, ammine complex salts and the like are preferred. Further, the content ratio of Pd ion and / or Ni ion in the aqueous solution can be appropriately adjusted so that the content ratio of Pd and Ni in the obtained methane oxidation catalyst 100 is a desired content ratio, and is not particularly limited. For example, the above-mentioned alumina-based base material particles 11 (raw material alumina powder) are impregnated or immersed in such a solution to remove the solvent (for example, water), and if necessary, a drying treatment and / or about 200 to 600 ° C. By performing the heat treatment (firing treatment) of the above, the composite particles 21 containing Pd and Ni supported on the surface 11a of the alumina-based base material particles 11 can be obtained with good productivity.
　なお、焼成条件は、常法にしたがえばよく、特に限定されない。焼成雰囲気は、酸化性雰囲気、還元性雰囲気、中性雰囲気のいずれの雰囲気でもよい。生産性等の観点からは、一般的には、１５０℃～１３００℃で０．１～１２時間が好ましく、より好ましくは３５０℃～６００℃で０．１～４時間である。ここで、高温焼成に先立って、真空乾燥機等を用いて減圧乾燥を行い、約５０℃～２００℃で約１～４８時間程度の乾燥処理を行ってもよい。 Note that the firing conditions may be in accordance with a conventional method and are not particularly limited. The firing atmosphere may be any of an oxidizing atmosphere, a reducing atmosphere, and a neutral atmosphere. From the viewpoint of productivity and the like, generally, it is preferably 0.1 to 12 hours at 150 ° C to 1300 ° C, and more preferably 0.1 to 4 hours at 350 ° C to 600 ° C. Here, prior to high-temperature firing, vacuum drying may be performed using a vacuum dryer or the like, and drying treatment may be performed at about 50 ° C. to 200 ° C. for about 1 to 48 hours.
　得られる複合粒子２１は、アルミナ系母材粒子１１の表面１１ａ上にＰｄとＮｉが共担持された複合構造を有し、これらＰｄ及びＮｉは、主たる触媒活性サイトとして機能する。なお、要求性能に応じて、複合粒子２１の粒度調整を行ってもよい。複合粒子２１の粒度調整は、常法にしたがって行うことができ、特に限定されない。好ましい一態様では、例えば複合粒子２１を湿式ミリング処理等することにより、例えば平均粒子径（Ｄ９０）を３～５０μｍとすることが好ましく、より好ましくは５～４０μｍ、さらに好ましくは１０～３０μｍである。 The obtained composite particle 21 has a composite structure in which Pd and Ni are co-supported on the surface 11a of the alumina-based base particle 11, and these Pd and Ni function as main catalytically active sites. The particle size of the composite particles 21 may be adjusted according to the required performance. The particle size of the composite particle 21 can be adjusted according to a conventional method, and is not particularly limited. In a preferred embodiment, for example, the composite particles 21 are preferably wet-milled to have an average particle diameter (D90) of 3 to 50 μm, more preferably 5 to 40 μm, and even more preferably 10 to 30 μm. ..
　本実施形態のメタン酸化触媒１００は、メタンを含むガスに複合粒子２１を曝すことでメタンを酸化（酸化除去）する触媒能を呈する。メタン酸化触媒１００の使用形態は、特に限定されない。例えば、上述した複合粒子２１の集合体である触媒粉末の形態で、そのまま用いることができる。また、例えば、複合粒子２１を任意の形状に成形して、粒状やペレット状の成形触媒とすることができる。なお、成形触媒の作製時には、各種公知の分散装置、混練装置、成形装置を用いることができる。 The methane oxidation catalyst 100 of the present embodiment exhibits a catalytic ability to oxidize (oxidize and remove) methane by exposing the composite particles 21 to a gas containing methane. The form of use of the methane oxidation catalyst 100 is not particularly limited. For example, it can be used as it is in the form of the catalyst powder which is an aggregate of the composite particles 21 described above. Further, for example, the composite particles 21 can be molded into an arbitrary shape to obtain a granular or pellet-shaped molding catalyst. When producing the molding catalyst, various known dispersion devices, kneading devices, and molding devices can be used.
　さらに、本実施形態のメタン酸化触媒１００は、モノリス担体等の触媒担体上に担持させた形態でも用いることができる。この形態は、触媒担体と、この触媒担体上に支持された、メタン酸化触媒１００（複合粒子２１）を含有する触媒層とを備える、積層触媒として定義できる。ここで、積層触媒の触媒エリアは、触媒層が１つのみの単層であっても、２以上の触媒層からなる積層体であってもよく、１以上の触媒層と当業界で公知の１以上の他の層とを組み合わせた積層体のいずれでもよい。なお、ここで用いる触媒担体としては、当業界で公知のものを適宜選択することができる。代表的には、コージェライト製、シリコンカーバイド製、窒化珪素製等のセラミックモノリス担体、ステンレス製等のメタルハニカム担体、ステンレス製等のワイヤメッシュ担体等が挙げられるが、これらに特に限定されない。なお、これらは、１種のみを単独で、又は２種以上の任意の組み合わせ及び割合で用いることができる。 Further, the methane oxidation catalyst 100 of the present embodiment can also be used in a form of being supported on a catalyst carrier such as a monolith carrier. This form can be defined as a laminated catalyst comprising a catalyst carrier and a catalyst layer containing a methane oxidation catalyst 100 (composite particles 21) supported on the catalyst carrier. Here, the catalyst area of the laminated catalyst may be a single layer having only one catalyst layer or a laminated body composed of two or more catalyst layers, and is known in the art as one or more catalyst layers. It may be any of the laminated bodies in which one or more other layers are combined. As the catalyst carrier used here, a catalyst carrier known in the art can be appropriately selected. Typical examples thereof include ceramic monolith carriers made of cordierite, silicon carbide, silicon nitride and the like, metal honeycomb carriers made of stainless steel and the like, wire mesh carriers made of stainless steel and the like, but are not particularly limited thereto. It should be noted that these can be used alone or in any combination and ratio of two or more.
　触媒層の形成方法は、常法にしたがって行えばよく、特に限定されない。各種公知のコーティング法、ウォッシュコート法、ゾーンコート法を適用することができる。一例を挙げると、本実施形態の本実施形態のメタン酸化触媒１００と、水系媒体と、必要に応じて当業界で公知のバインダー、他の触媒、助触媒粒子、ＯＳＣ材、母材粒子、添加剤等とを所望の配合割合で混合してスラリー状混合物を調製し、得られたスラリー状混合物を触媒担体の表面に付与し、乾燥、焼成することができる。この際、必要に応じてｐＨ調整のために酸や塩基を配合したり、粘性の調整やスラリー分散性向上のための界面活性剤や分散用樹脂等を配合したりすることができる。なお、スラリーの混合方法としては、ボールミル等による粉砕混合が適用可能であるが、他の粉砕、或いは混合方法を適用することもできる。そして、スラリー状混合物の付与後においては、常法にしたがい乾燥や焼成を行うことにより、本実施形態のメタン酸化触媒１００を含有する触媒層を触媒担体上に備える、積層触媒（メタン酸化積層触媒）を得ることができる。 The method for forming the catalyst layer may be performed according to a conventional method, and is not particularly limited. Various known coating methods, wash coat methods, and zone coat methods can be applied. As an example, the methane oxidation catalyst 100 of the present embodiment of the present embodiment, an aqueous medium, and optionally a binder known in the art, other catalysts, co-catalyst particles, OSC material, base material particles, addition. A slurry-like mixture can be prepared by mixing the agent and the like in a desired blending ratio, and the obtained slurry-like mixture can be applied to the surface of the catalyst carrier, dried and fired. At this time, if necessary, an acid or a base can be blended for pH adjustment, or a surfactant, a dispersion resin, or the like for adjusting the viscosity or improving the slurry dispersibility can be blended. As a method for mixing the slurry, pulverization and mixing using a ball mill or the like can be applied, but other pulverization or mixing methods can also be applied. Then, after the slurry-like mixture is added, the catalyst layer containing the methane oxidation catalyst 100 of the present embodiment is provided on the catalyst carrier by drying and firing according to a conventional method (methane oxidation laminated catalyst). ) Can be obtained.
　メタン酸化触媒１００の塗工量は、所望性能に応じて適宜設定でき、特に限定されないが、塗工量や圧力損失等の観点から、基材となる触媒担体１Ｌに対して、１００ｇ／Ｌ以上２００ｇ／Ｌ以下であることが好ましく、より好ましくは１００ｇ／Ｌ以上１８０ｇ／Ｌ以下、さらに好ましくは１１０ｇ／Ｌ以上１５０ｇ／Ｌ以下である。 The coating amount of the methane oxidation catalyst 100 can be appropriately set according to the desired performance and is not particularly limited, but is 100 g / L or more with respect to 1 L of the catalyst carrier as a base material from the viewpoint of the coating amount and pressure loss. It is preferably 200 g / L or less, more preferably 100 g / L or more and 180 g / L or less, and further preferably 110 g / L or more and 150 g / L or less.
　Ｐｄの塗工量は、所望性能に応じて適宜設定でき、特に限定されないが、基材となる触媒担体１Ｌに対して、４．５ｇ／Ｌ以上１６．０ｇ／Ｌ以下であることが好ましく、より好ましくは５．０ｇ／Ｌ以上１４．０ｇ／Ｌ以下、さらに好ましくは６．０ｇ／Ｌ以上１２．０ｇ／Ｌ以下である。 The coating amount of Pd can be appropriately set according to the desired performance and is not particularly limited, but is preferably 4.5 g / L or more and 16.0 g / L or less with respect to 1 L of the catalyst carrier as a base material. It is more preferably 5.0 g / L or more and 14.0 g / L or less, and further preferably 6.0 g / L or more and 12.0 g / L or less.
　Ｎｉの塗工量は、所望性能に応じて適宜設定でき、特に限定されないが、基材となる触媒担体１Ｌに対して、１．０ｇ／Ｌ以上１１．０ｇ／Ｌ以下であることが好ましく、より好ましくは２．０ｇ／Ｌ以上９．５ｇ／Ｌ以下、さらに好ましくは５．０ｇ／Ｌ以上８．０／Ｌ以下である。 The amount of Ni coated can be appropriately set according to the desired performance and is not particularly limited, but is preferably 1.0 g / L or more and 11.0 g / L or less with respect to 1 L of the catalyst carrier as a base material. It is more preferably 2.0 g / L or more and 9.5 g / L or less, and further preferably 5.0 g / L or more and 8.0 / L or less.
　以上詳述したとおり、本実施形態のメタン酸化触媒１００は、ガス中に含まれるメタンを酸化するための酸化触媒として有用である。具体的には、圧縮天然ガス（ＣＮＧ）、液化天然ガス（ＬＮＧ）、都市ガス、軽油、灯油等を燃料として用いるボイラー、加熱炉、ガスエンジン、ガスタービン、希薄燃焼ガスエンジン、その他の内燃機関等から排出されるガスに含まれるメタンの酸化触媒として、本実施形態のメタン酸化触媒１００を用いることができる。 As described in detail above, the methane oxidation catalyst 100 of the present embodiment is useful as an oxidation catalyst for oxidizing methane contained in the gas. Specifically, boilers, heating furnaces, gas engines, gas turbines, dilute combustion gas engines, and other internal combustion engines that use compressed natural gas (CNG), liquefied natural gas (LNG), city gas, light oil, kerosene, etc. as fuel. As the oxidation catalyst of methane contained in the gas discharged from the gas such as, the methane oxidation catalyst 100 of the present embodiment can be used.
　また、本実施形態のメタン酸化触媒１００は、ディーゼルエンジン等の圧縮点火内燃機関、これを用いるバイフューエルエンジン（ＢＦ）やデュアルフューエルエンジン（ＣＮＧ－ＤＦＣＩ、ＬＮＧ－ＤＦＣＩ等）等から排出される排ガスに含まれるメタンの酸化触媒として殊に有用である。この場合、例えばディーゼルエンジンの排ガス流路中に本実施形態のメタン酸化触媒１００を配置し、その後に、ディーゼル酸化触媒（ＤＯＣ：Diesel Oxidation Catalyst）；排ガス中に含まれる煤等の粒子状物質（ＰＭ：Particulate matter）を捕集するためのディーゼル微粒子捕集フィルター（ＤＰＦ：Diesel Particulate Filler）、触媒塗工ＰＦ（ＣＰＦ：Catalyzed Particulate Filler）或いは触媒化燃焼フィルター（ＣＳＦ：Catalyzed Soot Filter）；リーン条件下でＮＯｘを吸蔵しリッチ条件下でＮＯｘを放出してＣＯやＨＣをＣＯ２やＨ２Ｏに酸化するとともにＮＯｘをＮ２に還元するリーンＮＯｘ吸蔵触媒（ＬＮＴ、Lean NOx Trap）；選択的触媒還元（ＳＣＲ：Selective Catalytic Reduction触媒）；アンモニア酸化触媒（ＡＭＯＸ：Ammonia Oxidation catalyst）等を適宜設けた形で実施可能である。なお、これらの配置順序や設置個数は、要求性能に応じて適宜変更でき、上記の例に限定されない。 Further, the methane oxidation catalyst 100 of the present embodiment is exhaust gas discharged from a compressed ignition internal combustion engine such as a diesel engine, a bi-fuel engine (BF) or a dual fuel engine (CNG-DFCI, LNG-DFCI, etc.) using the compressed ignition internal combustion engine. It is particularly useful as an oxidation catalyst for methane contained in. In this case, for example, the methane oxidation catalyst 100 of the present embodiment is placed in the exhaust gas flow path of a diesel engine, and then the diesel oxidation catalyst (DOC); a particulate substance such as soot contained in the exhaust gas (DOC). Diesel Particulate Filler (DPF) for collecting PM: Particulate matter, Catalyzed Particulate Filler (CPF) or Catalyzed Soot Filter (CSF); Lean condition A lean NOx particulate filter (LNT, Lean NOx Trap) that absorbs NOx underneath and releases NOx under rich conditions to oxidize CO and HC to CO 2 and H 2 O and reduce NOx to N 2 . It can be carried out by appropriately providing a catalytic reduction (SCR: Selective Catalytic Reduction catalyst); an ammonia oxidation catalyst (AMOX: Ammonia Oxidation catalyst) or the like. The arrangement order and the number of these arrangements can be appropriately changed according to the required performance, and are not limited to the above example.
　以下、実施例を用いて本発明の内容をさらに具体的に説明するが、本発明はその要旨を超えない限り、以下の実施例によって何ら限定されるものではない。すなわち、以下の実施例に示す材料、使用量、割合、処理内容、処理手順等は、本発明の趣旨を逸脱しない限り、適宜変更することができる。なお、以下の実施例における各種の製造条件や評価結果の値は、本発明の実施態様における上限又は下限の好ましい値としての意味を持つものであり、好ましい範囲は前記した上限又は下限の好ましい値としての意味をもつものであり、好ましい範囲は前記した上限又は下限の値と、下記実施例の値又は実施例同士の値との組み合わせで規定される範囲であってもよい。 Hereinafter, the content of the present invention will be described in more detail using examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. That is, the materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. The values of various production conditions and evaluation results in the following examples have meanings as preferable values of the upper limit or the lower limit in the embodiment of the present invention, and the preferable range is the preferable value of the upper limit or the lower limit described above. The preferred range may be a range defined by a combination of the above-mentioned upper limit or lower limit value and the value of the following examples or the values of the examples.
［アルミナ系母材粒子１１の細孔径及び細孔容量］
　アルミナ系母材粒子１１の細孔分布は、水銀圧入法により求める。ここでは、アルミナ系母材粒子１１０．２ｇをサンプルとして用い、水銀ポロシメーター（Thermo Fisher Scientific社製、商品名：PASCAL140及びPASCAL440）を用いて、水銀の接触角１３０°及び表面張力４８４ｄｙｎ／ｃｍの条件下にて細孔容積を測定し、このとき得られる細孔径－微分細孔容量の細孔分布曲線におけるピークトップ位置の値（モード径）を、アルミナ系母材粒子１１の細孔径とする。 [Pore diameter and pore capacity of alumina-based base material particles 11]
The pore distribution of the alumina-based base material particles 11 is determined by the mercury intrusion method. Here, 110.2 g of alumina-based base material particles are used as a sample, and a mercury porosimeter (manufactured by Thermo Fisher Scientific, trade names: PASCAL140 and PASCAL440) is used under the conditions of a mercury contact angle of 130 ° and a surface tension of 484 dyn / cm. The pore volume is measured below, and the value (mode diameter) of the peak top position in the pore distribution curve of the pore diameter-differential pore volume obtained at this time is taken as the pore diameter of the alumina-based base material particles 11.
［アルミナ系母材粒子１１の平均粒子径Ｄ５０］
　レーザ回折式粒度分布測定装置（例えば、島津製作所社製、レーザ回折式粒度分布測定装置ＳＡＬＤ－７１００等）を用いて粒度分布を測定し、そのメディアン径をアルミナ系母材粒子１１の平均粒子径Ｄ５０とする。 [Average particle diameter D50 of alumina-based base material particles 11]
The particle size distribution is measured using a laser diffraction type particle size distribution measuring device (for example, a laser diffraction type particle size distribution measuring device SALD-7100 manufactured by Shimadzu Corporation), and the median diameter thereof is the average particle size of the alumina-based base material particles 11. Let it be D50.
［ＢＥＴ比表面積の測定］
　ＢＥＴ比表面積は、比表面積／細孔分布測定装置（商品名：BELSORP-mini II、マイクロトラック・ベル株式会社製）及び解析用ソフトウェア（商品名：BEL_Master、マイクロトラック・ベル株式会社製）を用いて、ＢＥＴ一点法により、ＢＥＴ比表面積を求める。 [Measurement of BET specific surface area]
For the BET specific surface area, use a specific surface area / pore distribution measuring device (trade name: BELSORP-mini II, manufactured by Microtrac Bell Co., Ltd.) and analysis software (trade name: BEL_Master, manufactured by Microtrac Bell Co., Ltd.). Then, the BET specific surface area is obtained by the BET one-point method.
（実施例１）
　アルミナ系母材粒子（Ｓａｓｏｌ製、商品名：ＴＨ１００／１５０、ＢＥＴ比表面積：１５０ｍ２／ｇ、平均粒子径Ｄ５０：３２μｍ、細孔径（ピーク値）：１７．２ｎｍ、細孔容積：１．８２ｃｃ／ｇ）を用いた。硝酸Ｐｄ水溶液及び硝酸ニッケル（ＩＩ）六水和物水溶液を混合し、Ｐｄ塩及びＮｉ塩を含む水溶液（Ｐｄ換算で３．６質量％含有、Ｎｉ換算で１．６質量％含有）を調製した。このＰｄ塩及びＮｉ塩を含む水溶液に、上記のアルミナ系母材粒子を含浸させて、アルミナ系母材粒子上にＰｄとＮｉとを共担持させ、その後、５００℃で１時間焼成することにより、アルミナ系母材粒子上にＰｄ及びＮｉが担持された複合粒子を形成した後、湿式ミリング法により平均粒子径Ｄ９０が１４～１８μｍの範囲内になるまで混錬し、実施例１のメタン酸化触媒（Ｐｄ換算で３．０質量％含有、Ｎｉ換算で１．６質量％含有）を得た。 (Example 1)
Alumina-based base particle (manufactured by Sasol, trade name: TH100 / 150, BET specific surface area: 150 m 2 / g, average particle diameter D50: 32 μm, pore diameter (peak value): 17.2 nm, pore volume: 1.82 cc / G) was used. An aqueous solution of Pd nitrate and an aqueous solution of nickel (II) nitrate hexahydrate were mixed to prepare an aqueous solution containing a Pd salt and a Ni salt (containing 3.6% by mass in terms of Pd and 1.6% by mass in terms of Ni). .. The aqueous solution containing the Pd salt and the Ni salt is impregnated with the above alumina-based base material particles to co-support Pd and Ni on the alumina-based base material particles, and then fired at 500 ° C. for 1 hour. After forming composite particles in which Pd and Ni are supported on the alumina-based base material particles, the particles are kneaded by a wet milling method until the average particle diameter D90 is within the range of 14 to 18 μm, and the methane oxidation of Example 1 is carried out. A catalyst (containing 3.0% by mass in terms of Pd and 1.6% by mass in terms of Ni) was obtained.
（比較例１）
　硝酸Ｎｉ水溶液の使用を省略する以外は、実施例１と同様に行い、比較例１のメタン酸化触媒（Ｐｄ換算で３．０質量％含有）を得た。 (Comparative Example 1)
The same procedure as in Example 1 was carried out except that the use of the Nitric acid Nitric acid aqueous solution was omitted, to obtain the methane oxidation catalyst of Comparative Example 1 (containing 3.0% by mass in terms of Pd).
（比較例２）
　硝酸Ｎｉ水溶液に代えて、硝酸テトラアンミン白金(II)水溶液を用いる以外は、実施例１と同様に行い、比較例２のメタン酸化触媒（Ｐｔ換算で０．６質量％含有、Ｐｄ換算で３．０質量％含有）を得た。 (Comparative Example 2)
The same procedure as in Example 1 was carried out except that an aqueous solution of tetraammine platinum (II) nitrate was used instead of the aqueous solution of Ni nitric acid. (Containing 0% by mass) was obtained.
（比較例３）
　硝酸Ｎｉ水溶液に代えて、硝酸セリウム（IV）六水和物水溶液を用いる以外は、実施例１と同様に行い、比較例３のメタン酸化触媒（Ｐｄ換算で３．０量％含有、Ｃｅ換算で１０．０質量％含有）を得た。 (Comparative Example 3)
The same procedure as in Example 1 was carried out except that an aqueous solution of cerium (IV) nitrate hexahydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 3 (containing 3.0% by weight in Pd conversion, converted to Ce). (Containing 10.0% by mass) was obtained.
〔性能評価〕
　得られた実施例１及び比較例１～３のメタン酸化触媒をそれぞれ５０ｍｇ分取し、以下の条件でメタン酸化除去性能を評価した。結果を、図２に示す。
〔測定条件〕
　・ガス組成  ：1000ppm-CH4, 8%-O2, 2%-H2O He balance
　・Total流量 ：300cc/min
　・ガス分析  ：FT-IR 
　・評価温度　：600℃→200℃降温/100℃毎
　・触媒　　  ：50mg [Performance evaluation]
50 mg of each of the obtained methane oxidation catalysts of Example 1 and Comparative Examples 1 to 3 was dispensed, and the methane oxidation removal performance was evaluated under the following conditions. The results are shown in FIG.
〔Measurement condition〕
・ Gas composition: 1000ppm-CH 4 , 8% -O 2 , 2% -H 2 O He balance
・ Total flow rate: 300cc / min
・ Gas analysis: FT-IR
・ Evaluation temperature: 600 ℃ → 200 ℃ lower temperature / every 100 ℃ ・ Catalyst: 50mg
（比較例４）
　硝酸Ｎｉ水溶液に代えて、硝酸マグネシウム（II）六水和物水溶液を用いる以外は、実施例１と同様に行い、比較例４のメタン酸化触媒（Ｐｄ換算で３．０質量％含有、Ｍｇ換算で０．７質量％含有）を得た。 (Comparative Example 4)
The same procedure as in Example 1 was carried out except that an aqueous solution of magnesium (II) nitrate hexahydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 4 (containing 3.0% by mass in terms of Pd, converted to Mg). (Containing 0.7% by mass) was obtained.
（比較例５）
　硝酸Ｎｉ水溶液に代えて、硝酸コバルト（II）六水和物水溶液を用いる以外は、実施例１と同様に行い、比較例５のメタン酸化触媒（Ｐｄ換算で３．０質量％含有、Ｃｏ換算で１．７質量％含有）を得た。 (Comparative Example 5)
The same procedure as in Example 1 was carried out except that an aqueous solution of cobalt (II) nitrate hexahydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 5 (containing 3.0% by mass in terms of Pd, converted to Co). (Containing 1.7% by mass) was obtained.
（比較例６）
　硝酸Ｎｉ水溶液に代えて、酢酸バリウム（II）水溶液を用いる以外は、実施例１と同様に行い、比較例６のメタン酸化触媒（Ｐｄ換算で３．０質量％含有、Ｂａ換算で３．９質量％含有）を得た。 (Comparative Example 6)
The same procedure as in Example 1 was carried out except that an aqueous solution of barium (II) acetate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 6 (containing 3.0% by mass in terms of Pd and 3.9 in terms of Ba). (Containing% by mass) was obtained.
（比較例７）
　硝酸Ｎｉ水溶液に代えて、硝酸銅（II）三水和物水溶液を用いる以外は、実施例１と同様に行い、比較例７のメタン酸化触媒（Ｐｄ換算で３．０質量％含有、Ｃｕ換算で１．８質量％含有）を得た。 (Comparative Example 7)
The same procedure as in Example 1 was carried out except that an aqueous solution of copper (II) nitrate trihydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 7 (containing 3.0% by mass in terms of Pd, converted to Cu). (Containing 1.8% by mass) was obtained.
（比較例８）
　硝酸Ｎｉ水溶液に代えて、硝酸鉄（III）九水和物水溶液を用いる以外は、実施例１と同様に行い、比較例８のメタン酸化触媒（Ｐｄ換算で３．０質量％含有、Ｆｅ換算で１．６質量％含有）を得た。 (Comparative Example 8)
The same procedure as in Example 1 was carried out except that an aqueous solution of iron (III) nitrate hydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 8 (containing 3.0% by mass in terms of Pd, converted to Fe). (Containing 1.6% by mass) was obtained.
〔性能評価〕
　得られた実施例１及び比較例４～８のメタン酸化触媒をそれぞれ５０ｍｇ分取し、以下の条件でメタン酸化除去性能を評価した。結果を、図３に示す。
〔測定条件〕
　・ガス組成  ：1000ppm-CH4, 8%-O2, 2%-H2O He balance
　・Total流量 ：300cc/min
　・ガス分析  ：FT-IR 
　・評価温度　：600℃→200℃降温/100℃毎
　・触媒　　  ：50mg [Performance evaluation]
50 mg of each of the obtained methane oxidation catalysts of Example 1 and Comparative Examples 4 to 8 was dispensed, and the methane oxidation removal performance was evaluated under the following conditions. The results are shown in FIG.
〔Measurement condition〕
・ Gas composition: 1000ppm-CH 4 , 8% -O 2 , 2% -H 2 O He balance
・ Total flow rate: 300cc / min
・ Gas analysis: FT-IR
・ Evaluation temperature: 600 ℃ → 200 ℃ lower temperature / every 100 ℃ ・ Catalyst: 50mg
（比較例９）
　硝酸Ｎｉ水溶液に代えて、硝酸イットリウム（III）六水和物水溶液を用いる以外は、実施例１と同様に行い、比較例９のメタン酸化触媒（Ｐｄ換算で３．０質量％含有、Ｙ換算で２．５質量％含有）を得た。
として用いた。 (Comparative Example 9)
The same procedure as in Example 1 was carried out except that an aqueous solution of yttrium (III) nitrate hexahydrate was used instead of the aqueous solution of Ni nitric acid, and the methane oxidation catalyst of Comparative Example 9 (containing 3.0% by mass in Pd conversion, converted to Y). (Containing 2.5% by mass) was obtained.
Used as.
（比較例１０）
　硝酸Ｎｉ水溶液に代えて、硝酸セリウム（IV）六水和物水溶液を用いる以外は、実施例１と同様に行い、比較例１０のメタン酸化触媒（Ｐｄ換算で３．０質量％含有、Ｃｅ換算で３．９質量％含有）を得た。 (Comparative Example 10)
The same procedure as in Example 1 was carried out except that an aqueous solution of cerium (IV) nitrate hexahydrate was used instead of the aqueous solution of Ni nitrate, and the methane oxidation catalyst of Comparative Example 10 (containing 3.0% by mass in terms of Pd, converted to Ce). (Containing 3.9% by mass) was obtained.
（比較例１１）
　硝酸Ｎｉ水溶液に代えて、硝酸プラセオジム（III）六水和物水溶液を用いる以外は、実施例１と同様に行い、比較例１１のメタン酸化触媒（Ｐｄ換算で３．０質量％含有、Ｐｒ換算で４．０質量％含有）を得た。 (Comparative Example 11)
The same procedure as in Example 1 was carried out except that a praseodymium nitrate (III) hexahydrate aqueous solution was used instead of the Nitric acid Nitric acid aqueous solution, and the methane oxidation catalyst of Comparative Example 11 (containing 3.0% by mass in Pd conversion, Pr conversion). (Containing 4.0% by mass) was obtained.
（比較例１２）
　硝酸Ｎｉ水溶液に代えて、硝酸ネオジム（III）六水和物水溶液を用いる以外は、実施例１と同様に行い、比較例１２のメタン酸化触媒（Ｐｄ換算で３．０質量％含有、Ｎｄ換算で４．１質量％含有）を得た。 (Comparative Example 12)
The same procedure as in Example 1 was carried out except that an aqueous solution of neodymium (III) nitrate hexahydrate was used instead of the aqueous solution of Ni nitric acid, and the methane oxidation catalyst of Comparative Example 12 (containing 3.0% by mass in Pd conversion, converted to Nd). (Containing 4.1% by mass) was obtained.
〔性能評価〕
　得られた実施例１及び比較例９～１２のメタン酸化触媒をそれぞれ５０ｍｇ分取し、以下の条件でメタン酸化除去性能を評価した。結果を、図４に示す。
　・ガス組成  ：1000ppm-CH4, 8%-O2, 2%-H2O He balance
　・Total流量 ：300cc/min
　・ガス分析  ：FT-IR 
　・評価温度　：600℃→200℃降温/100℃毎
　・触媒　　  ：50mg [Performance evaluation]
50 mg of each of the obtained methane oxidation catalysts of Example 1 and Comparative Examples 9 to 12 was dispensed, and the methane oxidation removal performance was evaluated under the following conditions. The results are shown in FIG.
・ Gas composition: 1000ppm-CH 4 , 8% -O 2 , 2% -H 2 O He balance
・ Total flow rate: 300cc / min
・ Gas analysis: FT-IR
・ Evaluation temperature: 600 ℃ → 200 ℃ lower temperature / every 100 ℃ ・ Catalyst: 50mg
（実施例２）
　硝酸Ｐｄ水溶液及び硝酸ニッケル（ＩＩ）六水和物水溶液を混合して得た、Ｐｄ塩及びＮｉ塩を含む水溶液（Ｐｄ換算で３．６質量％含有、Ｎｉ換算で２．０質量％含有）に、アルミナ系母材粒子（Ｓａｓｏｌ製、商品名：ＴＨ１００／１５０、ＢＥＴ比表面積：１５０ｍ２／ｇ、平均粒子径Ｄ５０：３２μｍ、細孔径（ピーク値）：１７．２ｎｍ、細孔容積：１．８２ｃｃ／ｇ）を含浸させて、アルミナ系母材粒子上にＰｄとＮｉとを共担持させ、その後、４５０℃で０．５時間焼成することにより、アルミナ系母材粒子上にＰｄ及びＮｉが担持された複合粒子を形成した後、湿式ミリング法により平均粒子径Ｄ９０が１４～１８μｍの範囲内になるまで混錬し、実施例２のメタン酸化触媒（Ｐｄ換算で３．６質量％含有、Ｎｉ換算で２．０質量％含有）を得た。
　得られた実施例２のメタン酸化触媒を、コージェライト担体(ＮＧＫ社製、φ２５．４ｘ５０ｍｍ)上にウェットコーティングし（塗工量：１２５ｇ／Ｌ、Ｐｄ換算塗工量：４．５ｇ／Ｌ、Ｎｉ換算塗工量：２．５ｇ／Ｌ）、４５０℃で３０分間焼成処理することで、実施例２のメタン酸化積層触媒を得た。 (Example 2)
An aqueous solution containing a Pd salt and a Ni salt obtained by mixing an aqueous solution of Pd nitrate and an aqueous solution of nickel (II) nitrate hexahydrate (containing 3.6% by mass in terms of Pd and 2.0% by mass in terms of Ni). Alumina-based base particle (manufactured by Sasol, trade name: TH100 / 150, BET specific surface area: 150 m 2 / g, average particle diameter D50: 32 μm, pore diameter (peak value): 17.2 nm, pore volume: 1 .82cc / g) was impregnated to co-support Pd and Ni on the alumina-based base material particles, and then fired at 450 ° C. for 0.5 hours to cause Pd and Ni on the alumina-based base material particles. After forming the composite particles on which the particles were supported, the particles were kneaded by a wet milling method until the average particle diameter D90 was within the range of 14 to 18 μm, and the methane oxidation catalyst of Example 2 (containing 3.6% by mass in terms of Pd) was kneaded. , 2.0% by mass in terms of Ni) was obtained.
The obtained methane oxidation catalyst of Example 2 was wet-coated on a cordierite carrier (manufactured by NGK, φ25.4 x 50 mm) (coating amount: 125 g / L, Pd equivalent coating amount: 4.5 g / L, The methane oxidation laminated catalyst of Example 2 was obtained by firing treatment at 450 ° C. for 30 minutes at a Ni equivalent coating amount: 2.5 g / L).
（実施例３）
　使用するアルミナ系母材粒子を、アルミナ系母材粒子（Ｓａｓｏｌ製、商品名：Ｓｉｒａｌｏｘ１．５／１００、ＢＥＴ比表面積：１００ｍ２／ｇ、平均粒子径Ｄ５０：３７μｍ、細孔径（ピーク値）：１１．６ｎｍ、細孔容積：０．４６ｃｃ／ｇ）に変更する以外は、実施例２と同様に行って、実施例３のメタン酸化積層触媒を得た。 (Example 3)
The alumina-based base particle to be used is an alumina-based base particle (manufactured by Sasol, trade name: Silarox 1.5 / 100, BET specific surface area: 100 m 2 / g, average particle diameter D50: 37 μm, pore diameter (peak value) :. The same procedure as in Example 2 was carried out except that the particle volume was changed to 11.6 nm and the pore volume: 0.46 cc / g) to obtain the methane oxide laminated catalyst of Example 3.
（実施例４）
　使用するアルミナ系母材粒子を、アルミナ系母材粒子（Ｓｏｌｖａｙ製、商品名：ＭＩ３８６、ＢＥＴ比表面積：２００ｍ２／ｇ、平均粒子径Ｄ５０：２２μｍ、細孔径（ピーク値）：１０．４ｎｍ、細孔容積：１．００ｃｃ／ｇ）に変更する以外は、実施例２と同様に行って、実施例４のメタン酸化積層触媒を得た。 (Example 4)
The alumina-based base particle to be used is an alumina-based base particle (manufactured by Solvay, trade name: MI386, BET specific surface area: 200 m 2 / g, average particle diameter D50: 22 μm, pore diameter (peak value): 10.4 nm, The same procedure as in Example 2 was carried out except that the pore volume was changed to 1.00 cc / g) to obtain the methane oxide lamination catalyst of Example 4.
（実施例５）
　使用するアルミナ系母材粒子を、アルミナ系母材粒子（Ｓａｓｏｌ製、商品名：ＴＨ１３０／１３０、ＢＥＴ比表面積：１３０ｍ２／ｇ、平均粒子径Ｄ５０：２２μｍ、細孔径（ピーク値）：２６．２ｎｍ、細孔容積：２．２９ｃｃ／ｇ）に変更する以外は、実施例２と同様に行って、実施例５のメタン酸化積層触媒を得た。 (Example 5)
The alumina-based base particle to be used is an alumina-based base particle (manufactured by Sasol, trade name: TH130 / 130, BET specific surface area: 130 m 2 / g, average particle diameter D50: 22 μm, pore diameter (peak value): 26. The same procedure as in Example 2 was carried out except that the particle volume was changed to 2 nm and the pore volume: 2.29 cc / g) to obtain the methane oxide lamination catalyst of Example 5.
〔性能評価〕
　得られた実施例２～５のメタン酸化積層触媒について、モデルガスを用いて以下の条件でメタン浄化率の測定を行った。この測定では、ガス分析計（商品名：MEXA-7100・HORIBA製）を用いた。また、このとき用いたモデルガス組成を表１に示し、結果を図５及び図６に示す。
Figure JPOXMLDOC01-appb-T000001
 [Performance evaluation]
For the obtained methane oxidation laminated catalysts of Examples 2 to 5, the methane purification rate was measured under the following conditions using a model gas. In this measurement, a gas analyzer (trade name: MEXA-7100, manufactured by HORIBA) was used. The model gas composition used at this time is shown in Table 1, and the results are shown in FIGS. 5 and 6.
Figure JPOXMLDOC01-appb-T000001
（実施例６）
　Ｎｉの担持量をＰｄの担持量の３倍に変更する以外は、実施例２と同様に行い、実施例６のメタン酸化触媒（Ｐｄ換算で３．６質量％含有、Ｎｉ換算で６．０質量％含有）を得た。
　得られた実施例６のメタン酸化触媒を、コージェライト担体(φ２５．４ｘ５０ｍｍ)上にウェットコーティングし（塗工量：１２５ｇ／Ｌ、Ｐｄ換算塗工量：４．５ｇ／Ｌ、Ｎｉ換算塗工量：７．４ｇ／Ｌ）、４５０℃で３０分間焼成処理することで、実施例６のメタン酸化積層触媒を得た。 (Example 6)
The same procedure as in Example 2 was carried out except that the amount of supported Ni was changed to 3 times the amount of supported Pd, and the methane oxidation catalyst of Example 6 (containing 3.6% by mass in Pd conversion, 6.0 in Ni conversion) was carried out. (Containing% by mass) was obtained.
The obtained methane oxidation catalyst of Example 6 was wet-coated on a cordierite carrier (φ25.4 x 50 mm) (coating amount: 125 g / L, Pd equivalent coating amount: 4.5 g / L, Ni equivalent coating). Amount: 7.4 g / L) and firing treatment at 450 ° C. for 30 minutes to obtain the methane oxidation laminated catalyst of Example 6.
（実施例７）
　使用するアルミナ系母材粒子を、アルミナ系母材粒子（Ｓａｓｏｌ製、商品名：ＴＨ１３０／１３０、ＢＥＴ比表面積：１３０ｍ２／ｇ、平均粒子径Ｄ５０：２２μｍ、細孔径（ピーク値）：２６．２ｎｍ、細孔容積：２．２９ｃｃ／ｇ）に変更する以外は、実施例６と同様に行って、実施例７のメタン酸化積層触媒を得た。 (Example 7)
The alumina-based base particle to be used is an alumina-based base particle (manufactured by Sasol, trade name: TH130 / 130, BET specific surface area: 130 m 2 / g, average particle diameter D50: 22 μm, pore diameter (peak value): 26. The same procedure as in Example 6 was carried out except that the particle volume was changed to 2 nm and the pore volume: 2.29 cc / g) to obtain the methane oxide lamination catalyst of Example 7.
（実施例８）
　使用するアルミナ系母材粒子を、アルミナ系母材粒子（Ｓａｓｏｌ製、商品名：ＴＨ１００／１００、ＢＥＴ比表面積：１００ｍ２／ｇ、平均粒子径Ｄ５０：２９μｍ、細孔径（ピーク値）：２６．７ｎｍ、細孔容積：１．７８ｃｃ／ｇ）に変更する以外は、実施例６と同様に行って、実施例８のメタン酸化積層触媒を得た。 (Example 8)
The alumina-based base particle to be used is an alumina-based base particle (manufactured by Sasol, trade name: TH100 / 100, BET specific surface area: 100 m 2 / g, average particle diameter D50: 29 μm, pore diameter (peak value): 26. The same procedure as in Example 6 was carried out except that the particle volume was changed to 7 nm and the pore volume: 1.78 cc / g) to obtain the methane oxide lamination catalyst of Example 8.
（実施例９）
　使用するアルミナ系母材粒子を、アルミナ系母材粒子（Ｓａｓｏｌ製、商品名：ＴＭ１００／１５０、ＢＥＴ比表面積：１５０ｍ２／ｇ、平均粒子径Ｄ５０：２７μｍ、細孔径（ピーク値）：２４．８ｎｍ、細孔容積：１．６０ｃｃ／ｇ）に変更する以外は、実施例６と同様に行って、実施例９のメタン酸化積層触媒を得た。 (Example 9)
The alumina-based base particle to be used is an alumina-based base particle (manufactured by Sasol, trade name: TM100 / 150, BET specific surface area: 150 m 2 / g, average particle diameter D50: 27 μm, pore diameter (peak value): 24. The same procedure as in Example 6 was carried out except that the particle volume was changed to 8 nm and the pore volume: 1.60 cc / g) to obtain the methane oxide lamination catalyst of Example 9.
〔性能評価〕
　得られた実施例６～９のメタン酸化積層触媒について、上記と同様に、モデルガスを用いてメタン浄化率の測定を行った。結果を図７及び図８に示す。 [Performance evaluation]
For the obtained methane oxidation laminated catalysts of Examples 6 to 9, the methane purification rate was measured using a model gas in the same manner as described above. The results are shown in FIGS. 7 and 8.
〔Ｐｄ粒子径〕
　実施例２、６及び７、並びに比較例１のメタン酸化積層触媒を、日立ハイテクノロジーズ社製ＨＤ－２０００の走査透過型電子顕微鏡（ＳＴＥＭ）を用いて倍率１００万倍でそれぞれ観察し、アルミニウム系母材粒子上のＰｄ粒子の粒子径を測定した。なお、Ｐｄ粒子の粒子径は、得られた撮影像から無作為に選択した２０個のＰｄ粒子の粒径の相加平均値として示す。結果を図９に示す。 [Pd particle size]
The methane oxidation laminated catalysts of Examples 2, 6 and 7 and Comparative Example 1 were observed at a magnification of 1 million times using a scanning transmission electron microscope (STEM) of HD-2000 manufactured by Hitachi High-Technologies, respectively, and were made of aluminum. The particle size of the Pd particles on the base metal particles was measured. The particle size of the Pd particles is shown as an arithmetic mean value of the particle sizes of 20 Pd particles randomly selected from the obtained photographed images. The results are shown in FIG.
（実施例１０）
　テトラアンミンパラジウム（II）塩化物水和物水溶液及び硝酸ニッケル（ＩＩ）六水和物水溶液を混合して得た、Ｐｄ塩及びＮｉ塩を含む水溶液に、アルミナ系母材粒子（Ｓａｓｏｌ製、商品名：ＴＨ１００／１５０、ＢＥＴ比表面積：１５０ｍ２／ｇ、平均粒子径Ｄ５０：３２μｍ、細孔径（ピーク値）：１７．２ｎｍ、細孔容積：１．８２ｃｃ／ｇ）を含浸させて、アルミナ系母材粒子上にＰｄとＮｉとを共担持させ、その後、４５０℃で０．５時間焼成することにより、アルミナ系母材粒子上にＰｄ及びＮｉが担持された複合粒子を形成した後、湿式ミリング法により平均粒子径Ｄ９０が１４～１８μｍの範囲内になるまで混錬し、実施例１０のメタン酸化触媒（Ｐｄ換算で３．６質量％含有、Ｎｉ換算で６．０質量％含有）を得た。
　得られた実施例１０のメタン酸化触媒を、コージェライト担体(ＮＧＫ社製、φ２５．４ｘ５０ｍｍ)上にウェットコーティングし（塗工量：１２５ｇ／Ｌ、Ｐｄ換算塗工量：４．５ｇ／Ｌ、Ｎｉ換算塗工量：７．４ｇ／Ｌ））、４５０℃で３０分間焼成処理することで、実施例１０のメタン酸化積層触媒を得た。 (Example 10)
Alumina-based base material particles (manufactured by Sasol, trade name) in an aqueous solution containing a Pd salt and a Ni salt obtained by mixing an aqueous solution of tetraammine palladium (II) chloride hydrate and an aqueous solution of nickel (II) nitrate hexahydrate. : TH100 / 150, BET specific surface area: 150 m 2 / g, average particle diameter D50: 32 μm, pore diameter (peak value): 17.2 nm, pore volume: 1.82 cc / g) to impregnate the alumina-based mother. Pd and Ni are co-supported on the material particles and then fired at 450 ° C. for 0.5 hours to form composite particles in which Pd and Ni are supported on the alumina-based base material particles, and then wet milling. By the method, the particles are kneaded until the average particle size D90 is within the range of 14 to 18 μm to obtain the methane oxidation catalyst of Example 10 (containing 3.6% by mass in terms of Pd and 6.0% by mass in terms of Ni). rice field.
The obtained methane oxidation catalyst of Example 10 was wet-coated on a cordierite carrier (manufactured by NGK, φ25.4 x 50 mm) (coating amount: 125 g / L, Pd equivalent coating amount: 4.5 g / L, Ni-equivalent coating amount: 7.4 g / L))) was fired at 450 ° C. for 30 minutes to obtain the methane oxidation lamination catalyst of Example 10.
（実施例１１）
　使用するアルミナ系母材粒子を、アルミナ系母材粒子（Ｓａｓｏｌ製、商品名：ＴＨ１３０／１３０、ＢＥＴ比表面積：１３０ｍ２／ｇ、平均粒子径Ｄ５０：２２μｍ、細孔径（ピーク値）：２６．２ｎｍ、細孔容積：２．２９ｃｃ／ｇ）に変更する以外は、実施例１０と同様に行って、実施例１１のメタン酸化積層触媒を得た。 (Example 11)
The alumina-based base particle to be used is an alumina-based base particle (manufactured by Sasol, trade name: TH130 / 130, BET specific surface area: 130 m 2 / g, average particle diameter D50: 22 μm, pore diameter (peak value): 26. The same procedure as in Example 10 was carried out except that the particle volume was changed to 2 nm and the pore volume: 2.29 cc / g) to obtain the methane oxide lamination catalyst of Example 11.
〔性能評価〕
　得られた実施例１０～１１のメタン酸化積層触媒について、上記と同様に、モデルガスを用いてメタン浄化率の測定を行った。結果を図１０に示す。 [Performance evaluation]
For the obtained methane oxidation laminated catalysts of Examples 10 to 11, the methane purification rate was measured using a model gas in the same manner as described above. The results are shown in FIG.
（実施例１２～１６）
　ウェットコーティング時の塗工量を表２に示すとおりに変更する以外は、実施例７と同様に行い、実施例１２～１６のメタン酸化積層触媒を得た。 (Examples 12 to 16)
The same procedure as in Example 7 was carried out except that the amount of coating applied during wet coating was changed as shown in Table 2, to obtain methane oxidation laminated catalysts of Examples 12 to 16.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
〔性能評価〕
　得られた実施例７，１２～１６のメタン酸化積層触媒について、上記と同様に、モデルガスを用いてメタン浄化率の測定を行った。測定結果を図１１に示す。 [Performance evaluation]
For the obtained methane oxidation laminated catalysts of Examples 7, 12 to 16, the methane purification rate was measured using a model gas in the same manner as described above. The measurement results are shown in FIG.
　本発明のメタン酸化触媒及びメタン酸化積層触媒等は、ガス中に含まれるメタンの５００℃未満の低温領域での触媒活性が高められたものであるため、圧縮天然ガス（ＣＮＧ）、液化天然ガス（ＬＮＧ）、都市ガス、軽油、灯油等を燃料として用いるボイラー、加熱炉、ガスエンジン、ガスタービン、希薄燃焼ガスエンジン、その他の内燃機関等から排出されるガスに含まれるメタンの酸化触媒として、さらには、ディーゼルエンジン等の圧縮点火内燃機関、これを用いるバイフューエルエンジン（ＢＦ）やデュアルフューエルエンジン（ＣＮＧ－ＤＦＣＩ、ＬＮＧ－ＤＦＣＩ等）等から排出される排ガスに含まれるメタンの酸化触媒として殊に有効に利用可能である。 Since the methane oxidation catalyst, the methane oxidation laminated catalyst, and the like of the present invention have enhanced catalytic activity of methane contained in the gas in a low temperature region of less than 500 ° C., compressed natural gas (CNG), liquefied natural gas, etc. As an oxidation catalyst for methane contained in gas discharged from (LNG), city gas, light oil, kerosene and other boilers, heating furnaces, gas engines, gas turbines, dilute combustion gas engines, and other internal combustion engines. Furthermore, it is particularly used as an oxidation catalyst for methane contained in exhaust gas discharged from compression ignition internal combustion engines such as diesel engines, bifuel engines (BF) and dual fuel engines (CNG-DFCI, LNG-DFCI, etc.) using the same. It can be effectively used.
　　１００　・・・メタン酸化触媒
　　　１１　・・・アルミナ系母材粒子
　　　１１ａ・・・表面
　　　２１　・・・複合粒子
　　　Ｐｄ　・・・パラジウム
　　　Ｎｉ　・・・ニッケル 100 ・ ・ ・ Methane oxidation catalyst 11 ・ ・ ・ Alumina-based base particle 11a ・ ・ ・ Surface 21 ・ ・ ・ Composite particles Pd ・ ・ ・ Palladium Ni ・ ・ ・ Nickel

Claims (16)

  1. 　ガス中に含まれるメタンを酸化するためのメタン酸化触媒であり、
    　アルミナ系母材粒子、及び前記アルミナ系母材粒子上に担持されたＰｄとＮｉとを含有する複合粒子を含む、
    メタン酸化触媒。     It is a methane oxidation catalyst for oxidizing methane contained in gas.
    Alumina-based base material particles and composite particles containing Pd and Ni supported on the alumina-based base material particles are included.
    Methane oxidation catalyst.
  2. 　前記アルミナ系母材粒子が、５ｎｍ以上３０ｎｍ以下の細孔径を有する
    請求項１に記載のメタン酸化触媒。     The methane oxidation catalyst according to claim 1, wherein the alumina-based base material particles have a pore diameter of 5 nm or more and 30 nm or less.
  3. 　前記アルミナ系母材粒子が、５μｍ以上２００μｍ以下の平均粒子径Ｄ５０を有する
    請求項１又は２に記載のメタン酸化触媒。     The methane oxidation catalyst according to claim 1 or 2, wherein the alumina-based base material particles have an average particle diameter D50 of 5 μm or more and 200 μm or less.
  4. 　ＰｄとＮｉの含有モル比（Ｐｄ／Ｎｉ）が、１／１～１／３である
    請求項１～３のいずれか一項に記載のメタン酸化触媒。     The methane oxidation catalyst according to any one of claims 1 to 3, wherein the molar ratio of Pd to Ni (Pd / Ni) is 1/1 to 1/3.
  5. 　Ｐｄ及びＮｉの含有量が、前記複合粒子の総量に対する金属換算量で、それぞれ３～２０質量％である
    請求項１～４のいずれか一項に記載のメタン酸化触媒。     The methane oxidation catalyst according to any one of claims 1 to 4, wherein the contents of Pd and Ni are 3 to 20% by mass, respectively, in terms of metal with respect to the total amount of the composite particles.
  6. 　前記アルミナ系母材粒子が、α－アルミナ、γ－アルミナ、及びベーマイトよりなる群から選択される１種以上を含む
    請求項１～５のいずれか一項に記載のメタン酸化触媒。     The methane oxidation catalyst according to any one of claims 1 to 5, wherein the alumina-based base material particles include one or more selected from the group consisting of α-alumina, γ-alumina, and boehmite.
  7. 　前記アルミナ系母材粒子が、アルカリ金属元素、アルカリ土類金属元素、遷移元素、及び希土類元素よりなる群から選択される１種以上を含む
    請求項１～６のいずれか一項に記載のメタン酸化触媒。     The methane according to any one of claims 1 to 6, wherein the alumina-based base metal particles include at least one selected from the group consisting of an alkali metal element, an alkaline earth metal element, a transition element, and a rare earth element. Oxidation catalyst.
  8. 　前記アルミナ系母材粒子が、１．５ｃｃ／ｇ以上２．５ｃｃ／ｇ以下の細孔容積を有する
    請求項１～７のいずれか一項に記載のメタン酸化触媒。     The methane oxidation catalyst according to any one of claims 1 to 7, wherein the alumina-based base material particles have a pore volume of 1.5 cc / g or more and 2.5 cc / g or less.
  9. 　前記ガスが、内燃機関から排出される排ガスである
    請求項１～８のいずれか一項に記載のメタン酸化触媒。     The methane oxidation catalyst according to any one of claims 1 to 8, wherein the gas is an exhaust gas discharged from an internal combustion engine.
  10. 　前記ガスが、メタンを燃料として使用する内燃機関から排出される排ガスである
    請求項１～９のいずれか一項に記載のメタン酸化触媒。     The methane oxidation catalyst according to any one of claims 1 to 9, wherein the gas is an exhaust gas discharged from an internal combustion engine using methane as a fuel.
  11. 　ガス中に含まれるメタンを酸化するためのメタン酸化積層触媒であり、
    　触媒担体、並びに、前記触媒担体上に支持された触媒層を備え、
    　前記触媒層は、アルミナ系母材粒子、及び前記アルミナ系母材粒子に担持されたＰｄとＮｉとを含有する複合粒子を含むメタン酸化触媒を有する、
    メタン酸化積層触媒。     It is a methane oxidation laminated catalyst for oxidizing methane contained in gas.
    A catalyst carrier and a catalyst layer supported on the catalyst carrier are provided.
    The catalyst layer has an alumina-based base material particle and a methane oxidation catalyst containing composite particles containing Pd and Ni supported on the alumina-based base material particles.
    Methane oxidation laminated catalyst.
  12. 　前記触媒層の塗工量が、前記触媒担体１Ｌに対して、１００ｇ／Ｌ以上２００ｇ／Ｌ以下である
    請求項１１に記載のメタン酸化積層触媒。     The methane oxidation laminated catalyst according to claim 11, wherein the coating amount of the catalyst layer is 100 g / L or more and 200 g / L or less with respect to 1 L of the catalyst carrier.
  13. 　Ｐｄの塗工量が、前記触媒担体１Ｌに対して、４．５ｇ／Ｌ以上１６．０ｇ／Ｌ以下である
    請求項１１又は１２に記載のメタン酸化積層触媒。     The methane oxidation laminated catalyst according to claim 11 or 12, wherein the coating amount of Pd is 4.5 g / L or more and 16.0 g / L or less with respect to 1 L of the catalyst carrier.
  14. 　Ｎｉの塗工量が、前記触媒担体１Ｌに対して、１．０ｇ／Ｌ以上１１．０ｇ／Ｌ以下である
    請求項１１～１３のいずれか一項に記載のメタン酸化積層触媒。     The methane oxidation laminated catalyst according to any one of claims 11 to 13, wherein the coating amount of Ni is 1.0 g / L or more and 11.0 g / L or less with respect to 1 L of the catalyst carrier.
  15. 　内燃機関から排出される排ガスの排ガス流路に、アルミナ系母材粒子、及び前記アルミナ系母材粒子に担持されたＰｄとＮｉとを含有する複合粒子を含むメタン酸化触媒が配置された、
    排ガス浄化システム。     A methane oxidation catalyst containing alumina-based base material particles and composite particles containing Pd and Ni supported on the alumina-based base material particles was arranged in the exhaust gas flow path of the exhaust gas discharged from the internal combustion engine.
    Exhaust gas purification system.
  16. 　アルミナ系母材粒子をＰｄ塩及びＮｉ塩を含む溶液に浸漬し、前記アルミナ系母材粒子上にＰｄとＮｉとを共担持させ、前記アルミナ系母材粒子上にＰｄ及びＮｉが担持された複合粒子を形成する、
    メタン酸化触媒の製造方法。
          The alumina-based base material particles were immersed in a solution containing a Pd salt and a Ni salt, Pd and Ni were co-supported on the alumina-based base material particles, and Pd and Ni were supported on the alumina-based base material particles. Forming composite particles,
    Method for manufacturing methane oxidation catalyst.
PCT/JP2021/034080 2020-09-25 2021-09-16 Methane oxidation catalyst, methane oxidation multilayer catalyst, exhaust gas purification system using said methane oxidation catalyst or said methane oxidation multilayer catalyst, and method for producing methane oxidation catalyst WO2022065188A1 (en)

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Citations (6)

* Cited by examiner, † Cited by third party
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JPH06106059A (en) * 1991-03-27 1994-04-19 Mitsubishi Heavy Ind Ltd Oxidation catalyst
JP2002113367A (en) * 2000-10-10 2002-04-16 Toyota Central Res & Dev Lab Inc Catalyst for saturated hydrocarbon oxidation
JP2003071288A (en) * 2001-08-30 2003-03-11 Toyota Central Res & Dev Lab Inc Saturated hydrocarbon oxidation catalyst
WO2014141903A1 (en) * 2013-03-15 2014-09-18 エヌ・イーケムキャット株式会社 Oxidation catalyst and exhaust gas purification device using same
JP2016504182A (en) * 2012-11-29 2016-02-12 ビーエーエスエフ ソシエタス・ヨーロピアＢａｓｆ Ｓｅ Diesel oxidation catalyst containing palladium, gold and ceria
JP2016215091A (en) * 2015-05-15 2016-12-22 株式会社 Ａｃｒ Binary fuel oxidation catalyst, binary fuel scr exhaust gas treatment mechanism, binary fuel diesel internal combustion engine and controlling method therefor

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06106059A (en) * 1991-03-27 1994-04-19 Mitsubishi Heavy Ind Ltd Oxidation catalyst
JP2002113367A (en) * 2000-10-10 2002-04-16 Toyota Central Res & Dev Lab Inc Catalyst for saturated hydrocarbon oxidation
JP2003071288A (en) * 2001-08-30 2003-03-11 Toyota Central Res & Dev Lab Inc Saturated hydrocarbon oxidation catalyst
JP2016504182A (en) * 2012-11-29 2016-02-12 ビーエーエスエフ ソシエタス・ヨーロピアＢａｓｆ Ｓｅ Diesel oxidation catalyst containing palladium, gold and ceria
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