JP2017521241A - Molecular sieve catalyst composition, catalyst composite, system, and method - Google Patents

Abstract

A selective catalytic reduction catalyst is described comprising a zeolite framework material of silicon and aluminum atoms, wherein a portion of said silicon atoms are isomorphously substituted with a tetravalent metal. The catalyst may include a promoter metal so that it effectively promotes the reaction of ammonia and nitrogen oxides to selectively form nitrogen and H2O over a temperature range of 150C to 650C. In another aspect, a selective catalytic reduction complex is described that includes an SCR catalyst material and an ammonia storage material comprising a transition metal having an oxidation number IV. The SCR catalyst material effectively promotes the reaction between ammonia and nitrogen oxides to selectively form nitrogen and H 2 O over a temperature range of 150 ° C. to 600 ° C., and the SCR catalyst material has a temperature of 400 ° C. or higher. Effective for storing ammonia at temperature. A method of selectively reducing nitrogen oxides and a method of simultaneously performing selective reduction of nitrogen oxides and storage of ammonia are also described. Further, an exhaust gas treatment system is also described.

Description

  The present invention relates generally to the field of selective catalytic reduction materials, selective catalytic reduction complexes, and methods for selectively reducing nitrogen oxides. More specifically, embodiments of the present invention relate to an SCR catalyst material comprising spherical particles that include agglomeration of molecular sieve crystals.

The harmful components of nitrogen oxides (NO _x ) cause air pollution over time. NO _x is contained in exhaust gases from internal combustion engine (eg, automobiles and trucks), combustion equipment (eg, power plants heated by natural gas, oil or coal) and nitric acid production plants.

Various methods have been used for the treatment of NO _x containing gas mixtures. One type of treatment involves the catalytic reduction of nitrogen oxides. There are two processes: (1) a non-selective reduction process using carbon monoxide, hydrogen or lower hydrocarbon as a reducing agent, and (2) a selective reduction process using ammonia or an ammonia precursor as a reducing agent. In the selective reduction process, a high removal of nitrogen oxides can be achieved with a small amount of reducing agent.

The selective reduction process is called the SCR process (selective catalytic reduction). Used in this SCR process is the catalytic reduction of nitrogen oxides with ammonia in the presence of atmospheric oxygen, mainly involving the formation of nitrogen and steam:
4NO + 4NH ₃ + O ₂ → 4N ₂ + 6H ₂ O (standard SCR reaction)
2NO ₂ + 4NH ₃ → 3N ₂ + 6H ₂ O (slow SCR reaction)
NO + NO ₂ + NH ₃ → 2N ₂ + 3H ₂ O (fast SCR reaction)

  The catalyst used in the SCR process should ideally be able to maintain good catalytic activity under hydrothermal conditions, for example over a wide use temperature condition of 200 ° C. to 600 ° C. or higher. In fact, hydrothermal conditions often occur, such as during regeneration of soot filters, ie, components of exhaust gas treatment systems used for particle removal.

  Molecular sieves such as zeolites have been used for selective catalytic reduction (SCR) of nitrogen oxides with reducing agents such as ammonia, urea or hydrocarbons in the presence of oxygen. Zeolite is a crystalline material with a fairly uniform pore size, the pore size range being about 3 mm in diameter, depending on the type of zeolite and the type and amount of cations contained in the zeolite lattice. -10 angstroms. Zeolite having an 8-ring pore opening and a double hexacyclic secondary structure unit, particularly a zeolite having a cage-like structure, has recently found interest for use as an SCR catalyst. A specific type of zeolite with these properties is chabasite (CHA), which is a small pore zeolite with an 8-membered ring pore opening (~ 3.8 angstroms) accessible by its three-dimensional porosity. It is. A cage-like structure results from the connection of double hexacyclic structural units by four rings.

  Metal-promoted zeolite catalysts, such as iron-promoted zeolite catalysts and copper-promoted zeolite catalysts, are known for the selective catalytic reduction of nitrogen oxides with ammonia. Iron-promoted zeolite beta was an effective commercial catalyst for the selective reduction of nitrogen oxides with ammonia. Unfortunately, it has been found that under the severe hydrothermal conditions shown during regeneration of soot filters, for example locally above 700 ° C., the activity of many metal-promoted zeolites begins to decline. . This reduction is often attributed to the dealumination of the zeolite and thus the resulting loss of metal-containing active centers within the zeolite.

  Metal-promoted, especially copper-promoted aluminosilicate zeolites with the CHA structure type have recently received much interest as catalysts for SCR of nitrogen oxides in lean burn engines using nitrogen-containing reducing agents. . This is because, as described in US Pat. No. 7,601,662 (United States Patent Number 7,601,662), these materials have a wide temperature window with excellent hydrothermal durability. Because it is. Prior to the discovery of the metal-promoted zeolites described in US Pat. No. 7,601,662, the literature shows that a number of metal-promoted zeolites have been identified in the patent and scientific literature as SCR. Although proposed for use as a catalyst, each proposed material had one or both of the following disadvantages: (1) Insufficient nitrogen oxides at low temperatures, eg, 350 ° C. and below (2) Insufficient hydrothermal stability clearly indicated by a significant reduction in catalytic activity in the conversion of nitrogen oxides by SCR.

  Thus, the invention described in US Pat. No. 7,601,662 is a material that provides nitrogen oxide conversion at low temperatures and retention of SCR catalytic activity after hydrothermal degradation at temperatures above 650 ° C. Set an urgent unresolved issue to provide.

Despite the excellent properties of current catalysts, there is a constant desire to reduce the N ₂ O production (make) during the SCR reaction. Accordingly, there is a need for an SCR catalyst with improved NO _x conversion efficiency and lower N ₂ O production compared to current technology.

Summary A first aspect of the invention relates to a selective catalytic reduction (SCR) material. In a first embodiment, the selective catalytic reduction material comprises spherical particles comprising aggregates of molecular sieve crystals, wherein the spherical particles have a median particle size in the range of about 0.5 to about 5 microns. Have

  In the second embodiment, the SCR catalyst material of the first embodiment is modified, where the molecular sieve includes d6r units.

  In the third embodiment, the SCR catalyst material of the first and second embodiments is modified, wherein the molecular sieve is AEI, AFT, AFX, CHA, EAB, EMT, ERI, FAU, GME, JSR, Has a structural type selected from the group consisting of KFI, LEV, LTL, LTN, MOZ, MSO, MWW, OFF, SAS, SAT, SAV, SBS, SBT, SFW, SSF, SZR, TSC, WEN and combinations thereof .

  In the fourth embodiment, the SCR catalyst material of the first to third embodiments is modified, where the molecular sieve is AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, SAS, SAT and It has a structural type selected from SAV.

  In the fifth embodiment, the SCR catalyst material of the first to fourth embodiments is modified, wherein the molecular sieve has a structural type selected from AEI, CHA and AFX.

  In the sixth embodiment, the SCR catalyst material of the first to fifth embodiments is modified, wherein the molecular sieve has a CHA structural type.

  In the seventh embodiment, the SCR catalyst material of the first to sixth embodiments is modified, wherein the molecular sieve having the CHA structure type is aluminosilicate zeolite, borosilicate, gallosilicate, SAPO, AlPO, MeAPSO. And MeAPO.

  In the eighth embodiment, the SCR catalyst material of the first to seventh embodiments is modified, wherein the molecular sieve having the CHA structure type is SSZ-13, SSZ-62, natural chabazite, zeolite K- Selected from the group consisting of G, Linde D, Linde R, LZ-218, LZ-235, LZ-236, ZK-14, SAPO-34, SAPO-44, SAPO-47 and ZYT-6.

  In the ninth embodiment, the SCR catalyst material of the first to eighth embodiments is modified, wherein the molecular sieve is selected from SSZ-13 and SSZ-62.

  In the tenth embodiment, the SCR catalyst material of the first to ninth embodiments is modified, where the molecular sieve is Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag and their Promoted with a metal selected from a combination.

  In the eleventh embodiment, the SCR catalyst material of the first to tenth embodiments is modified, wherein the molecular sieve is promoted with a metal selected from Cu, Fe, and combinations thereof.

  In the twelfth embodiment, the SCR catalyst material of the first to eleventh embodiments is modified, wherein the SCR catalyst material is selected from nitrogen oxides in the presence of a reducing agent at a temperature of 200 ° C. to 600 ° C. Effective in catalyzing catalytic catalytic reduction.

  In the thirteenth embodiment, the SCR catalyst material of the sixth embodiment is modified, wherein the molecular sieve having the CHA structure type has a silica / alumina ratio in the range of 10-100.

  In a fourteenth embodiment, the SCR catalyst material of the tenth and eleventh embodiments is modified, wherein the metal is present in an amount ranging from about 0.1 to about 10 weight percent on an oxide basis.

  In a fifteenth embodiment, the SCR catalyst material of the first to fourteenth embodiments is modified, wherein the spherical particles have a median particle size in the range of about 1.2 to about 3.5 microns.

  In the sixteenth embodiment, the SCR catalyst material of the first to fifteenth embodiments is modified, wherein the crystals have a crystal size in the range of about 1 to about 250 nm.

  In the seventeenth embodiment, the SCR catalyst material of the first to sixteenth embodiments is modified, wherein the crystals have a crystal size in the range of about 100 to about 250 nm.

  In an eighteenth embodiment, the SCR catalyst material of the first to seventeenth embodiments is modified, where the SCR catalyst material takes the form of a washcoat.

  In the nineteenth embodiment, the SCR catalyst material of the eighteenth embodiment is modified, where the washcoat is a layer deposited on the substrate.

  In the twentieth embodiment, the SCR catalyst material of the nineteenth embodiment is modified, wherein the substrate comprises a filter.

  In the twenty-first embodiment, the SCR catalyst material of the twentieth embodiment is modified, wherein the filter is a wall flow filter.

  In the twenty-second embodiment, the SCR catalyst material of the twentieth embodiment is modified, wherein the filter is a flow-through filter.

  In a twenty-third embodiment, the SCR catalyst material of the first to twenty-second embodiments is modified, wherein at least 80% of the spherical particles have a median particle size in the range of 0.5 to 2.5 microns. .

  In the twenty-fourth embodiment, the SCR catalyst material of the first to twenty-third embodiments is modified, wherein the molecular sieve includes a zeolitic framework material of silicon atoms and aluminum atoms, wherein a portion of the silicon atoms is Isomorphic substitution with a tetravalent metal.

  In the twenty-fifth embodiment, the SCR catalyst material of the twenty-fourth embodiment is modified, wherein the molecular sieve is selected from Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag, and combinations thereof Be promoted with metal.

  In a twenty-sixth embodiment, the SCR catalyst material of the twenty-fourth and twenty-fifth embodiments is modified, wherein the tetravalent metal includes a tetravalent transition metal.

  In a twenty-seventh embodiment, the SCR catalyst material of the twenty-fourth to twenty-sixth embodiments is modified, wherein the tetravalent transition metal is selected from the group consisting of Ti, Zr, Hf, Ge, and combinations thereof. The

  In the twenty-eighth embodiment, the SCR catalyst material of the twenty-fourth to twenty-seventh embodiments is modified, wherein the tetravalent transition metal comprises Ti.

A second aspect of the present invention relates to a method for selectively reducing nitrogen oxides (NO _x ). In an embodiment of the 29, nitrogen oxides method of selectively reducing the (NO _x) is an exhaust gas stream containing NO _x, SCR catalytic material comprising spherical particles include aggregates of crystals of the molecular sieve Wherein the spherical particles have a median particle size in the range of about 0.5 to about 5 microns. In another embodiment, a method for selectively reducing nitrogen oxides (NO _x ) includes contacting an exhaust gas stream containing NO _x with the SCR catalyst material of the first to twenty-eighth embodiments. .

A third aspect of the present invention relates to a system for treating exhaust gases from lean-burn engines containing NO _x. In a thirtieth embodiment, a system for treating exhaust gas from a lean burn engine containing NO _x includes the SCR catalyst material of the first through twenty-eighth embodiments and at least one other exhaust gas treatment component. Including.

  The thirty-first embodiment includes a zeolite framework material of silicon atoms and aluminum atoms, wherein a part of the silicon atoms is isomorphously substituted with a tetravalent metal, and the catalyst is Cu, Fe, Co, Ni, La Relates to a metal promoted SCR catalyst selected from Ce, Mn, V, Ag and combinations thereof.

  In a thirty-second embodiment, the SCR catalyst of the thirty-first embodiment is modified, wherein the tetravalent metal includes a tetravalent transition metal.

  In a thirty-third embodiment, the SCR catalyst of the thirty-first and thirty-second embodiments is modified, wherein the tetravalent transition metal is selected from the group consisting of Ti, Zr, Hf, Ge, and combinations thereof. .

  In the thirty-fourth embodiment, the SCR catalyst of the thirty-first to thirty-third embodiments is modified, wherein the tetravalent transition metal includes Ti.

  In a thirty-fifth embodiment, the SCR catalyst composite of the thirty-first to thirty-fourth embodiments is modified, wherein the silica / alumina ratio is in the range of 1-300.

  In the thirty-sixth embodiment, the SCR catalyst composite of the thirty-first to thirty-fifth embodiments is modified, wherein the silica / alumina ratio is in the range of 1-50.

  In the thirty-seventh embodiment, the SCR catalyst composite of the thirty-first to thirty-sixth embodiments is modified, wherein the tetravalent metal / alumina ratio is in the range of 0.0001-1000.

  In the thirty-eighth embodiment, the SCR catalyst of the thirty-first to thirty-seventh embodiments is modified, wherein the tetravalent metal / alumina ratio is in the range of 0.01-10.

  In the thirty-ninth embodiment, the SCR catalyst of the thirty-first to thirty-eighth embodiments is modified, wherein the tetravalent metal / alumina ratio is in the range of 0.01-2.

  In the 40th embodiment, the SCR catalyst of the 31st to 39th embodiments is modified, wherein the silica / 4 valent metal ratio is in the range of 1-100.

  In the forty-first embodiment, the SCR catalyst of the thirty-first to forty-first embodiments is modified, wherein the silica / 4 valent metal ratio is in the range of 5-20.

  In a forty-second embodiment, the SCR catalyst of the thirty-first to forty-first embodiments is modified, wherein the zeolitic framework material has a ring size of 12 or less.

  In a forty-third embodiment, the SCR catalyst of the thirty-first to forty-second embodiments is modified, wherein the zeolitic framework material includes d6r units.

  In the forty-fourth embodiment, the SCR catalyst of the thirty-first to forty-third embodiments is modified, wherein the zeolite framework material is AEI, AFT, AFX, CHA, EAB, EMT, ERI, FAU, GME, JSR, It is selected from KFI, LEV, LTL, LTN, MOZ, MSO, MWW, OFF, SAS, SAT, SAV, SBS, SBT, SFW, SSF, SZR, TSC, WEN and combinations thereof.

  In a forty-fifth embodiment, the SCR catalyst of the thirty-first to forty-fourth embodiments is modified, wherein the zeolitic framework material is selected from AEI, CHA, AFX, ERI, KFI, LEV and combinations thereof.

  In the forty-sixth embodiment, the SCR catalyst of the thirty-first to forty-fifth embodiments is modified, wherein the zeolitic framework material is selected from AEI, CHA and AFX.

  In the 47th embodiment, the SCR catalyst of the 31st to 46th embodiments is modified, wherein the zeolite framework material is CHA.

  In the forty-eighth embodiment, the SCR catalyst of the thirty-first to forty-seventh embodiments is modified, wherein the catalyst is promoted with Cu, Fe, and combinations thereof.

In a forty-ninth embodiment, the SCR catalyst of the thirty-first to forty-eighth embodiments is modified, where the catalyst is effective to promote the formation of NO ⁺ .

  In the 50th embodiment, the SCR catalyst of the 31st to 49th embodiments is modified, except that the zeolite skeleton does not contain a phosphorus atom.

An embodiment of an additional aspect of the present invention relates to a method for selectively reducing nitrogen oxides (NO _x ). In a fifty-first embodiment, a method for selectively reducing nitrogen oxides (NO _x ) includes contacting an exhaust gas stream containing NO _x with the catalyst of the thirty-first to fifty-fifth embodiments.

  An embodiment of a further aspect of the invention relates to an exhaust gas treatment system. In a 52nd embodiment, an exhaust gas treatment system includes an exhaust gas stream containing ammonia and a catalyst according to the 31st to 50th embodiments.

In another aspect, the 53rd embodiment relates to the use of the catalyst of any of the 1st to 50th embodiments as a catalyst for the selective catalytic reduction of NO _{x in} the presence of ammonia.

The 54th embodiment includes a SCR catalyst material that promotes a reaction between ammonia and nitrogen oxides to selectively form nitrogen and H ₂ O over a temperature range of 150 ° C. to 600 ° C., and a transition having an oxidation number IV For an SCR catalyst composite comprising an ammonia storage material comprising a metal, the SCR catalyst material is effective for storing ammonia above 400 ° C., and a minimum NH ₃ storage at 400 ° C. is 0.1 g / L. It is.

  In a 55th embodiment, the SCR catalyst composite of the 54th embodiment is modified, wherein the transition metal is selected from the group consisting of Ti, Ce, Zr, Hf, Ge, and combinations thereof.

  In a 56th embodiment, the SCR catalyst bodies of the 54th and 55th embodiments are modified, wherein the SCR catalyst material is isomorphously replaced with an ammonia storage material.

  In a 57th embodiment, the SCR catalyst composite of the 54th and 55th embodiments is modified, wherein the ammonia storage material is dispersed in the SCR catalyst material.

  In a 58th embodiment, the SCR catalyst composite of the 54th and 55th embodiments is modified, wherein the ammonia storage material is dispersed as a layer on the SCR catalyst material.

  In the 59th embodiment, the SCR catalyst composite of the 54th and 55th embodiments is modified, wherein the ammonia storage material and the SCR catalyst material are arranged in a zone.

  In the 60th embodiment, the SCR catalyst composite of the 59th embodiment is modified, wherein the ammonia storage material is upstream of the SCR catalyst material.

  In the 61st embodiment, the SCR catalyst composite of the 54th and 55th embodiments is modified, wherein the SCR catalyst material is ion exchanged with an ammonia storage material.

  In a 62nd embodiment, the SCR catalyst composite of the 54th through 61st embodiments is modified, wherein the SCR catalyst material is disposed on a filter.

  In the 63rd embodiment, the SCR catalyst composite of the 62nd embodiment is modified, wherein the filter is a wall flow filter.

  In the 64th embodiment, the SCR catalyst composite of the 62nd embodiment is modified, wherein the filter is a flow-through filter.

  In a 65th embodiment, the SCR catalyst composite of the 54th to 64th embodiments is modified, wherein the SCR catalyst material comprises a molecular sieve, a mixed oxide, and an activated refractory metal oxide support. Including one or more of them.

  In the 66th embodiment, the SCR catalyst composite of the 65th embodiment is modified, wherein the mixed oxide is Fe / titania, Fe / alumina, Mg / titania, Mg / alumina, Mn / alumina, Mn / Titania, Cu / titania, Ce / Zr, Ti / Zr, vanadia / titania and mixtures thereof.

  In a 67th embodiment, the SCR catalyst composite of the 65th and 66th embodiments is modified, wherein the mixed oxide comprises vanadia / titania and is stabilized with tungsten.

  In the 68th embodiment, the SCR catalyst composite of the 65th embodiment is modified, wherein the molecular sieve has a skeleton of silicon atoms, phosphorus atoms and aluminum atoms.

  In a 69th embodiment, the SCR catalyst composite of the 68th embodiment is modified, wherein the silica / alumina ratio is in the range of 1-300.

  In the 70th embodiment, the SCR catalyst composite of the 68th and 69th embodiments is modified, wherein the silica / alumina ratio is in the range of 1-50.

  In the 71st embodiment, the SCR catalyst composite of the 68th to 70th embodiments is modified, wherein the alumina / 4valent metal ratio is in the range of 1:10 to 10: 1.

  In the 72nd embodiment, the SCR catalyst composite of the 68th to 71st embodiments is modified, wherein a portion of the silicon ions are isomorphously replaced with the metal of the ammonia storage material.

  In the 73rd embodiment, the SCR catalyst complex of the 65th embodiment is modified, wherein the molecular sieve has a ring size of 12 or less.

  In the 72nd embodiment, the SCR catalyst complex of the 65th to 73rd embodiment is modified, wherein the molecular sieve is MFI, BEA, AEI, AFT, AFX, CHA, EAB, EMT, ERI, FAU. , GME, JSR, KFI, LEV, LTL, LTN, MOZ, MSO, MWW, OFF, SAS, SAT, SAV, SBS, SBT, SFW, SSF, SZR, TSC, WEN and combinations thereof Has a structural type.

  In the 73rd embodiment, the SCR catalyst complex of the 72nd embodiment is modified, wherein the molecular sieve is a group consisting of MFI, BEA, CHA, AEI, AFX, ERI, KFI, LEV and combinations thereof. Having a structural type selected from

  In the 74th embodiment, the SCR catalyst complex of the 73rd embodiment is modified, wherein the molecular sieve has a structural type selected from the group consisting of AEI, CHA, AFX, and combinations thereof.

  In the 75th embodiment, the SCR catalyst composite of the 54th to 74th embodiments is modified, wherein the SCR catalyst material is Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag and Promoted with metals selected from their combination.

  In the 76th embodiment, the SCR catalyst composite of the 54th to 74th embodiments is modified, wherein the SCR catalyst material is promoted with Cu, Fe, and combinations thereof.

  In the 77th embodiment, the SCR catalyst complex of the 65th embodiment is modified, wherein the molecular sieve comprises SSZ-13, SSZ-39 or SAPO-34.

  In the 78th embodiment, the SCR catalyst composite of the 65th embodiment is modified, wherein the activated refractory metal oxide support is alumina, ceria, zirconia, silica, titania, silica-alumina, Zirconia-Alumina, Titania-Alumina, Lantana-Alumina, Lantana-Zirconia-Alumina, Barrier-Alumina, Barrier-Lantana-Alumina, Barrier-Lantana-Neodymia-Alumina, Alumina-Cromia, Alumina-Ceria, Zirconia-Silica, Titania- It is selected from silica, or zirconia-titania, and combinations thereof.

  In the 79th embodiment, the SCR catalyst composite of the 78th embodiment is modified, wherein the activated refractory metal oxide support is Cu, Fe, Co, Ni, La, Ce, Mn, Exchanged with a metal selected from the group consisting of V, Ag and combinations thereof.

  In the 80th embodiment, the SCR catalyst composite of the 65th embodiment is modified, wherein the transition metal comprises Ti.

  In the 81st embodiment, the SCR catalyst composite of the 80th embodiment is modified, wherein the alumina / titanium ratio is in the range of 1:10 to 10: 1.

A further aspect of the invention relates to a method. In the 82nd embodiment, the method of simultaneously performing selective reduction of nitrogen oxides (NO _x ) and storage of ammonia, the exhaust gas stream containing NO _x is converted into the SCR of the 54th to 81st embodiments. Contacting with the catalyst complex.

  In the 83rd embodiment, the method of the 82nd embodiment is modified, wherein the oxygen content of the exhaust gas stream is 1-30% and the moisture content of the exhaust gas stream is 1-20%. .

A further aspect of the invention relates to an SCR catalyst complex. In the 84th embodiment, the SCR catalyst composite effectively promotes the reaction between ammonia and nitrogen oxides to selectively form nitrogen and H ₂ O over a temperature range of 200 ° C. to 600 ° C. Material (wherein the SCR catalyst material comprises SSZ-13) and an ammonia storage material comprising Ti, which is effective for storing ammonia at 400 ° C. or higher.

FIG. 1 is a schematic cross-sectional view of an SCR catalyst material according to one or more embodiments. FIG. 2 is a partial cross-sectional view of an SCR catalyst composite according to one or more embodiments. FIG. 3 is a partial cross-sectional view of an SCR catalyst composite according to one or more embodiments. FIG. 4A is a perspective view of a wall flow filter base material. FIG. 4B is a diagram showing a partial cutaway view of the wall flow type filter substrate. FIG. 5 is a diagram showing an SEM image showing a crystal form of the catalyst material according to the example. FIG. 6 is a view showing an SEM image showing a crystal form of a catalyst material according to a comparative example. FIG. 7 is a graph showing a bar graph for comparing the NO _x conversion rates of the catalysts according to the examples. FIG. 8 is a graph showing a bar graph comparing the amount of N ₂ O produced by the catalyst according to the example. FIG. 9 is a graph showing a comparison of NO _x conversion rates of catalysts according to Examples. FIG. 10 is a graph showing a comparison of the amount of N ₂ O produced by the catalyst according to the example. FIG. 11 is a graph showing a bar graph for comparing the NO _x conversion rate at 20 ppm NH ₃ slip of the catalyst according to the example. FIG. 12 is a diagram showing an ATR analysis of a catalyst according to an example. FIG. 13 is a diagram showing FTIR analysis of a catalyst according to an example. FIG. 14 is a diagram showing FTIR analysis of a catalyst according to an example. FIG. 15 is a diagram showing a scanning electron microscope image of the material according to the example. FIG. 16 is a diagram comparing NO _x conversion rates of catalysts according to Examples. FIG. 17 is a diagram comparing NO _x conversion rates of catalysts according to Examples. FIG. 18A is a diagram showing a scanning electron microscope image of a material according to an example. FIG. 18B is a diagram showing a scanning electron microscope image of the material according to the example. FIG. 19 is a diagram showing the measurement of the washcoat porosity of the catalyst according to the example. FIG. 20 is a diagram comparing NH ₃ absorption of catalysts according to Examples. FIG. 21 is a diagram comparing NH ₃ absorption of catalysts according to Examples. FIG. 22 is a diagram comparing NH ₃ absorption of catalysts according to Examples. FIG. 23 is a diagram comparing NH ₃ absorption of catalysts according to Examples. FIG. 24 is a diagram comparing NH ₃ absorption of catalysts according to Examples.

DETAILED DESCRIPTION Before describing some exemplary embodiments of the present invention, it is to be understood that the present invention is not limited to the details of construction or process steps set forth in the following description. The invention is capable of other embodiments and of being practiced or carried out in various ways.

The ordinance, use of the NO _x reduction technologies for lightweight vehicles and heavy vehicles is obligatory. Selective catalytic reduction (SCR) of NO _x using urea is an efficient and dominant emission control technique for NO _x control. In order to meet the ordinance, there is a need for an SCR catalyst with improved performance compared to current Cu-SSZ-13 based benchmark technology. An SCR catalyst material having improved NO _x conversion efficiency and lower N ₂ O production compared to current Cu—SSZ-13 based benchmark technology is provided. The SCR catalyst material effectively promotes the reaction between ammonia and nitrogen oxide to selectively form nitrogen and H ₂ O over a temperature range of 200 to 600 ° C.

  Embodiments of the present invention relate to a selective catalytic reduction material comprising spherical particles that include agglomerates of molecular sieve crystals. Surprisingly, it has been found that spherical particles having an aggregate of molecular sieve crystals are particularly suitable in the exhaust gas purification catalyst component, especially as an SCR catalyst material.

  The terms used in the present disclosure are defined as follows.

  The term “catalyst” or “catalyst composition” or “catalytic material” as used herein refers to a material that promotes the reaction.

  As used herein, the term “catalyst article” or “catalyst complex” refers to an element used to promote a desired reaction. For example, the catalyst article or catalyst composite may have a washcoat containing a catalyst species, such as a catalyst composition, on a substrate.

As used herein, the term “selective catalytic reduction” (SCR) refers to a catalytic process in which nitrogen oxides are reduced to dinitrogen (N ₂ ) using a nitrogen-containing reducing agent.

  As used herein, the term “FTIR” refers to Fourier transform infrared spectroscopy, which obtains an infrared spectrum of absorption, emission, photoconductivity or Raman scattering of a solid, liquid or gas. Is the technology used for

  As used herein, the term “ATR” refers to attenuated total reflectance spectroscopy, which is a sampling technique used with infrared spectroscopy, particularly FTIR, and thus without further preparation of the sample. It is possible to directly inspect in a solid state or a liquid state.

  According to one or more embodiments, the selective catalytic reduction catalyst material comprises spherical particles comprising aggregates of molecular sieve crystals, wherein the spherical particles range from about 0.5 to about 5 microns. Having a median particle size of

  As used herein, the term “molecular sieve” refers to framework materials such as zeolites and other framework materials (eg, isomorphously substituted materials), which are one or more promoters used as catalysts. It may be particulate with the metal. Molecular sieves are materials based on a broad three-dimensional network of oxygen ions, and generally include tetrahedral sites and have a substantially uniform pore distribution with an average pore size of 20 cm or less. The size of the pores is defined by the size of the ring. The term “zeolite” as used herein refers to a specific example of a molecular sieve containing silicon and aluminum atoms. According to one or more embodiments, defining the molecular sieve by its structural type may be a structural type having the same structural type as the zeolite material and a framework material of any same structural type, such as SAPO, ALPO and MeAPO materials. It should be understood that it is intended to include.

  In a more particular embodiment, a reference to an aluminosilicate zeolite structure type limits the material to molecular sieves that do not contain phosphorus or other metals substituted in the framework. However, just in case, the term “aluminosilicate zeolite” as used herein excludes aluminophosphate materials such as SAPO, ALPO and MeAPO materials, and the broader term “zeolite” is Intended to include aluminosilicates and aluminophosphates. Zeolite is a crystalline material with a fairly uniform pore size, the pore size range depending on the type of zeolite and the type and amount of cations contained in the zeolite lattice. 10 angstroms. Zeolites generally have a silica / alumina (SAR) molar ratio of 2 or greater.

  The term “aluminophosphate” refers to another embodiment of a molecular sieve containing aluminum and phosphate atoms. Aluminophosphate is a crystalline material with a fairly uniform pore size.

In general, molecular sieves, such as zeolite, are defined as aluminosilicates having an open three-dimensional framework structure composed of apex-shared TO ₄ tetrahedra (where T is Al or Si, or optionally P). Is done. A cation that balances the charge of the anionic skeleton loosely binds to the skeleton oxygen, and the remaining pore volume is filled with water molecules. Non-skeletal cations are generally interchangeable and water molecules can be removed.

  In an exemplary embodiment, the molecular sieve may be isomorphously substituted. As used herein, the terms “zeolite framework” and “zeolite framework material” refer to specific examples of molecular sieves, which further include silicon and aluminum atoms. According to an embodiment of the present invention, the molecular sieve comprises a zeolite framework material of silicon (Si) ions and aluminum (Al) ions, wherein a portion of the silicon atoms are isomorphously substituted with a tetravalent metal. In certain embodiments, the backbone does not include a phosphorus (P) atom.

  As used herein, the terms “isomorphically substituted” and “isomorphic substitution” mean that there is no significant change in the crystal structure and one element in the mineral is replaced by another element. Refers to that. Elements that can be interchanged typically have similar ionic radii and valence states. In one or more embodiments, a portion of the silicon atoms are isomorphously substituted with a tetravalent metal. In other words, a part of silicon atoms in the zeolite framework material is replaced with a tetravalent metal. Such isomorphous substitution does not significantly change the crystal structure of the zeolite framework material.

  As used herein, the term “tetravalent metal” refers to a metal having a state with four electrons available for covalent chemical bonding at its valence (outermost electron shell). Tetravalent metals include germanium (Ge) and transition metals located in group 4 of the periodic table, titanium (Ti), zirconium (Zr) and hafnium (Hf). In one or more embodiments, the tetravalent metal is selected from Ti, Zr, Hf, Ge, and combinations thereof. In certain embodiments, the tetravalent metal includes Ti.

  In other embodiments, a portion of the silicon atoms are isomorphously substituted with a transition metal having an oxidation number of IV. While not intending to be bound by theory, it is believed that the presence of an element having a formal oxidation number IV helps to increase ammonia storage at high temperatures. In one or more embodiments, the transition metal having an oxidation number IV may be in the form of an oxide or may be substantially embedded in the SCR catalyst material. As used herein, the term “transition metal with oxidation number IV” refers to a metal having a state with four electrons available for covalent chemical bonding at its valence (outermost electron shell). Transition metals having an oxidation number IV include germanium (Ge), cerium (Ce), and transition metals located in group 4 of the periodic table, titanium (Ti), zirconium (Zr), and hafnium (Hf). In one or more embodiments, the transition metal having an oxidation number IV is selected from Ti, Ce, Zr, Hf, Ge, and combinations thereof. In certain embodiments, the transition metal having an oxidation number IV comprises Ti.

In one or more embodiments, the zeolitic framework material comprises a MO ₄ / SiO ₄ / AlO ₄ tetrahedron (where M is a tetravalent metal) and is bound by a common oxygen atom to form a three-dimensional structure. Form a network. The isomorphously substituted tetravalent metal is embedded in the zeolite framework material as tetrahedral atoms (MO ₄ ). The isomorphously substituted tetrahedral unit then forms a skeleton of the zeolitic material together with the silicon and aluminum tetrahedral units. In certain embodiments, the tetravalent metal comprises titanium and the zeolite framework material comprises a TiO ₄ / SiO ₄ / AlO ₄ tetrahedron. Thus, in one or more embodiments, the catalyst comprises a zeolite framework of silicon and aluminum atoms, wherein a portion of the silicon atoms are isomorphously substituted with titanium.

One or more embodiments of the isomorphously substituted zeolite framework material comprises a void network formed by a rigid network of MO ₄ / (SiO ₄ ) / AlO ₄ tetrahedra (where M is a tetravalent metal). Mainly distinguished according to the shape.

In one or more embodiments, the molecular sieve includes a SiO ₄ / AlO ₄ tetrahedron and is joined by a common oxygen atom to form a three-dimensional network. In other embodiments, the molecular sieve comprises a SiO ₄ / AlO ₄ / PO ₄ tetrahedron. The molecular sieve of one or more embodiments is mainly distinguished according to the shape of the void formed by the rigid network of (SiO ₄ ) / AlO ₄ or SiO ₄ / AlO ₄ / PO ₄ tetrahedron. The entrance to the void is formed from 6, 8, 10 or 12 ring atoms with respect to the atoms forming the entrance opening. In one or more embodiments, the molecular sieve has a ring size of 12 or less, such as 6, 8, 10, and 12, for example.

  According to one or more embodiments, the molecular sieve may be based on a skeletal topology in which the structure is identified. Typically, any structural type of zeolite such as ABW, ACO, AEI, AEL, AEN, AET, AFG, AFI, AFN, AFO, AFR, AFS, AFT, AFX, Afy, AHT, ANA, APC, APD , AST, ASV, ATN, ATO, ATS, ATT, ATV, AWO, AWW, BCT, BEA, BEC, BIK, BOG, BPH, BRE, CAN, CAS, SCO, CFI, SGF, CGS, CHA, CHI, CLO , CON, CZP, DAC, DDR, DFO, DFT, DOH, DON, EAB, EDI, EMT, EON, EPI, ERI, ESV, ETR, EUO, FAU, FER, FRA, GIS, GIU, GME, GON, GOO , HEU, IFR, IHW, ISV, ITE, ITH, ITW, IWR, IWW JBW, KFI, LAU, LEV, LIO, LIT, LOS, LOV, LTA, LTL, LTN, MAR, MAZ, MEI, MEL, MEP, MER, MFI, MFS, MON, MOR, MOZ, MSO, MTF, MTN, MTT, MTW, MWW, NAB, NAT, NES, NON, NPO, NSI, OBW, OFF, OSI, OSO, OWE, PAR, PAU, PHI, PON, RHO, RON, RRO, RSN, RTE, RTH, RUT, RWR, RWY, SAO, SAS, SAT, SAV, SBE, SBS, SBT, SFE, SFF, SFG, SFH, SFN, SFO, SGT, SOD, SOS, SSY, STF, STI, STT, TER, THO, TON, TSC, UEI, UFI, UOZ, USI, UTL, VET, VFI, NI, VSV, can be used WIE, WEN, YUG, structure type or their combinations ZON.

  In one or more embodiments, the molecular sieve comprises an 8-ring small pore aluminosilicate zeolite. As used herein, “small pores” refers to pore openings that are less than about 5 angstroms, for example on the order of ˜3.8 angstroms. The term “8-ring” zeolite means an 8-ring pore opening and a double hexacyclic secondary structure unit, and a cage-like structure formed by connecting double hexacyclic structure units by four rings. Refers to a zeolite having Zeolites are composed of secondary structural units (SBU) and composite structural units (CBU) and appear in many different framework structures. Secondary structural units contain up to 16 tetrahedral atoms and are achiral. The composite structural unit need not be achiral and may not necessarily be used to build the entire skeleton. For example, a group of zeolites has a single four-ring (s4r) composite structure unit in its framework structure. “4” in the tetracycle indicates the positions of tetrahedral silicon and aluminum atoms, and oxygen atoms are located between the tetrahedral atoms. Other composite structural units include, for example, a single six-ring (s6r) unit, a double four-ring (d4r) unit, and a double six-ring (d6r) unit. A d4r unit is created by connecting two s4r units. A d6r unit is created by connecting two s6r units. There are 12 tetrahedral atoms in the d6r unit. Zeolite structure types with d6r secondary structure units are AEI, AFT, AFX, CHA, EAB, EMT, ERI, FAU, GME, JSR, KFI, LEV, LTL, LTN, MOZ, MSO, MWW, OFF, SAS, Includes SAT, SAV, SBS, SBT, SFW, SSF, SZR, TSC and WEN.

In one or more embodiments, the molecular sieve includes d6r units. While not intending to be bound by theory, in one or more embodiments, d6r units are believed to promote the formation of NO ⁺ . Thus, in one or more embodiments, the molecular sieve is AEI, AFT, AFX, CHA, EAB, EMT, ERI, FAU, GME, JSR, KFI, LEV, LTL, LTN, MOZ, MSO, MWW, OFF, It has a structural type selected from SAS, SAT, SAV, SBS, SBT, SFW, SSF, SZR, TSC, WEN and combinations thereof. In another particular embodiment, the molecular sieve has a structural type selected from the group consisting of CHA, AEI, AFX, ERI, KFI, LEV and combinations thereof. In a more specific embodiment, the molecular sieve has a structural type selected from CHA, AEI and AFX. In one or more very specific embodiments, the molecular sieve has a CHA structural type.

Zeolitic chabazite are approximate _{expression: (Ca, Na 2, K} 2, Mg) Al tectosilicates minerals naturally occurring zeolites group having _{2 Si 4 O 12 · 6H 2} O ( e.g. hydrated calcium aluminum silicate) including. Three synthetic forms of zeolitic chabasite were published by John Wiley & Sons in 1973 by D.C. W. It is described in “Zeolite Molecular Sieves” by Breck, which is incorporated herein by reference. Three synthetic forms reported by Breck are zeolite KG (described in J. Chem. Soc, p. 2822 (1956), Barrer et.al); zeolite D (UK Patent Application No. 868,846). (Described in British Patent No. 868,846) (1961)); and zeolite R (described in US Pat. No. 3,030,181 (US Patent No. 3,030,181)), by referring to these Incorporated herein. The synthesis of SSZ-13, another synthetic form of zeolitic chabasite, is described in US Pat. No. 4,544,538 (US Pat. No. 4,544,538), which is incorporated herein by reference. Incorporate in the description. Silicoaluminophosphate 34 (SAPO-34), a synthetic form of molecular sieve having a chabasite crystal structure, is synthesized by US Pat. Nos. 4,440,871 and 7,264,789. It is described in the specification (US Patent No. 7,264,789), which is incorporated herein by reference. A method for producing SAPO-44, another synthetic molecular sieve having a chabasite structure, is described in US Pat. No. 6,162,415 (US Pat. No. 6,162,415), to which reference is made. Are incorporated herein by reference.

  In one or more embodiments, the molecular sieve may include all aluminosilicates, borosilicates, gallosilicates, MeAPSO and MeAPO compositions. These are SSZ-13, SSZ-62, natural chabasite, zeolite KG, Linde D, Linde R, LZ-218, LZ-235, LZ-236, ZK-14, SAPO-34, SAPO-44, Including, but not limited to, SAPO-47, ZYT-6, CuSAPO-34, CuSAPO-44 and CuSAPO-47.

  The ratio of silica to alumina in the aluminosilicate molecular sieve (silica / alumina ratio) may vary over a wide range. In one or more embodiments, the molecular sieve has a silica / alumina molar ratio (SAR) in the range of 2 to 300, such as 5 to 250; 5 to 200; 5 to 100; and 5 to 50. In one or more specific embodiments, the molecular sieve is 10-200, 10-100, 10-75, 10-60 and 10-50; 15-100, 15-75, 15-60 and 15-50; Silica / alumina molar ratio (SAR) in the range of 20-100, 20-75, 20-60 and 20-50. In a more specific embodiment, the molecular sieve has any of the SAR ranges of the previous section, and the spherical particles of the molecular sieve are from about 0.5 to about 5 microns, more specifically from about 1.0 to about The individual crystals of the molecular sieve have a median particle size in the range of 3.5 microns and have a crystal size in the range of about 100 to about 250 nm.

  Isomorphic substitution of silicon with a tetravalent metal can affect the silica / alumina ratio of the zeolite framework material. In one or more embodiments, the molecular sieve is isomorphously substituted with a tetravalent metal and silica in the range of 2-300, such as 5-250; 5-200; 5-100; and 5-50. / Alumina molar ratio (SAR). In one or more specific embodiments, the first and second molecular sieves are independently 10-200, 10-100, 10-75, 10-60 and 10-50; Having a silica / alumina molar ratio (SAR) in the range of 75, 15-60 and 15-50; 20-100, 20-75, 20-60 and 20-50.

  In embodiments where the molecular sieve is isomorphously substituted with a tetravalent metal, the tetravalent metal / alumina ratio may vary over a very wide range. Note that this ratio is an atomic ratio, not a molar ratio. In one or more embodiments, the ratio of tetravalent metal to alumina (tetravalent metal / alumina ratio) is in the range of 0.0001-10000, such as 0.0001-10000, 0.001-1000 and 0.001. It is in the range of 01-10. In other embodiments, the tetravalent metal / alumina ratio is in the range of 0.01-10, such as in the range of 0.01-10, 0.01-5, 0.01-2, and 0.01-1. is there. In certain embodiments, the tetravalent metal / alumina ratio is in the range of 0.01-2.

  In a particular embodiment where the molecular sieve is isomorphously substituted with a tetravalent metal, the tetravalent metal comprises titanium and the titania / alumina ratio is in the range of 0.0001-10000, such as 0.0001-10000, It exists in the range of 0.001-1000 and 0.01-10. In other embodiments, the titania / alumina ratio is in the range of 0.01 to 10, such as 0.01 to 10, 0.01 to 5, 0.01 to 2, and 0.01 to 1. In certain embodiments, the titania / alumina ratio is in the range of 0.01-2.

  The silica / tetravalent metal ratio may vary over a wide range. Note that this ratio is an atomic ratio, not a molar ratio. In one or more embodiments, the silica / 4valent metal ratio is in the range of 1-100, such as 1-50, 1-30, 1-25, 1-20, 5-20, and 10-20. is there. In certain embodiments, the silica / 4 valent metal ratio is about 15. In one or more embodiments, the tetravalent metal comprises titanium and the silica / titania ratio is in the range of 1-100, such as 1-50, 1-30, 1-25, 1-20, 5-20. And in the range of 10-20. In certain embodiments, the silica / titania ratio is about 15.

Promoter metal:
The molecular sieve of one or more embodiments may subsequently be ion exchanged with one or more promoter metals such as iron, copper, cobalt, nickel, cerium or platinum group metals. The synthesis of zeolites and related microporous and mesoporous materials depends on the structural type of the zeolitic material, but typically several components (eg silica, alumina, phosphorus, alkali metals) to form a synthetic gel A combination of organic templates, etc.) that is hydrothermally crystallized to form the final product. The structure directing agent may take the form of organics, ie tetraethylammonium hydroxide (TEAOH), or inorganic cations, ie Na ⁺ or K ⁺ . During crystallization, the tetrahedral units organize around the SDA to form the desired framework, and the SDA is often embedded within the pore structure of the zeolite crystal. In one or more embodiments, the crystallization of the molecular sieve can be obtained by the addition of structure directing agents / templates, crystal nuclei or elements. In some cases, crystallization can be performed at a temperature of less than 100 ° C.

  As used herein, the term “promoted” refers to a component that is intentionally added to the molecular sieve as opposed to impurities inherent in the molecular sieve. Thus, the cocatalyst is intentionally added to increase the activity of the catalyst as compared to a catalyst that does not have an intentionally added cocatalyst. To promote nitrogen oxide SCR, in one or more embodiments, a suitable metal is exchanged into the molecular sieve. According to one or more embodiments, the molecular sieve is promoted with a metal selected from Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag, and combinations thereof. In certain embodiments, the molecular sieve is promoted with Cu, Fe, and combinations thereof.

  The co-catalyst metal content of the molecular sieve calculated as oxide is at least about 0.1% by weight in one or more embodiments and is reported on the basis that it contains no volatiles. In certain embodiments, the co-catalyst metal comprises Cu and the Cu content calculated as CuO is based on the total mass of calcined molecular sieves reported on an oxide basis without volatile matter, It is in the range up to about 10% by weight, for example 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5 and 0.1% by weight. In certain embodiments, the Cu content calculated as CuO is in the range of about 2 to about 5 weight percent. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For a specific molecular sieve having a SAR of 2 to 300, the Cu content is 0.1 to 10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For a specific molecular sieve having a SAR of 5 to 250, the Cu content is 0.1 to 10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For a specific molecular sieve having a SAR of 5 to 200, the Cu content is 0.1 to 10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For specific molecular sieves having a SAR of 5 to 100, the Cu content is 0.1 to 10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For certain molecular sieves having a SAR of 5-50, the Cu content is 0.1-10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For a specific molecular sieve having a SAR of 10 to 250, the Cu content is 0.1 to 10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For a specific molecular sieve having a SAR of 10-200, the Cu content is 0.1-10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis, Alternatively, it may be in the range of 0.5-8% by mass, or 0.8-6% by mass, or 1-4% by mass, or even 2-3% by mass. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For a specific molecular sieve having a SAR of 10 to 100, the Cu content is 0.1 to 10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For a specific molecular sieve having a SAR of 10-75, the Cu content is 0.1-10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis, Alternatively, it may be in the range of 0.5-8% by mass, or 0.8-6% by mass, or 1-4% by mass, or even 2-3% by mass. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For certain molecular sieves having a SAR of 10-60, the Cu content is 0.1-10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For a specific molecular sieve having a SAR of 10-50, the Cu content is 0.1-10% by weight, based on the total weight of the calcined molecular sieve reported on a volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For certain molecular sieves having a SAR of 15-100, the Cu content is 0.1-10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For a specific molecular sieve having a SAR of 15-75, the Cu content is 0.1-10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis, Alternatively, it may be in the range of 0.5-8% by mass, or 0.8-6% by mass, or 1-4% by mass, or even 2-3% by mass. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For certain molecular sieves having a SAR of 15-60, the Cu content is 0.1-10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For certain molecular sieves having a SAR of 15-50, the Cu content is 0.1-10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For specific molecular sieves having a SAR of 20-100, the Cu content is 0.1-10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For specific molecular sieves having a SAR of 20-75, the Cu content is 0.1-10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For specific molecular sieves with a SAR of 20-60, the Cu content is 0.1-10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  For specific molecular sieves having a SAR of 20-50, the Cu content is 0.1-10% by weight, based on the total weight of the calcined molecular sieve reported on an volatile-free oxide basis, in each case. , Or 0.5-8 mass%, or 0.8-6 mass%, or 1-4 mass%, or even 2-3 mass%. In a more specific embodiment, the molecular sieve has this specific combination of SAR and Cu content, and the spherical particles of the molecular sieve are about 0.5 to about 5 microns, more specifically about 1. The individual crystals of the molecular sieve have a median particle size in the range of 2 to about 3.5 microns and the crystal size in the range of about 100 to about 250 nm.

  While not intending to be bound by theory, when the molecular sieve is isomorphously substituted with a tetravalent metal, the tetravalent metal is embedded in the zeolite framework as a tetrahedral atom, and structurally It is considered that it can be electronically bonded to the active promoter metal center. In one or more embodiments, the cocatalyst metal may be ion exchanged into an isomorphously substituted molecular sieve. In certain embodiments, copper may be ion exchanged into isomorphously substituted molecular sieves. This metal may be replaced after the preparation or manufacture of isomorphically substituted molecular sieves.

Porosity and particle shape and size:
In one or more embodiments, the catalyst material comprises spherical particles that include agglomerates of molecular sieve crystals. The term “aggregate” or “aggregation” as used herein refers to clusters or aggregates of primary particles, ie, crystals of molecular sieves.

  In one or more embodiments, the spherical particles range from about 0.5 to about 5 microns, such as 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,. 1, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.75, 2.0, 2.25, 2.5, 2.75, It has a median diameter in the range of 3.0, 3.25, 3.5, 3.75, 4, 4.24, 4.5, 4.75 and 5 microns. The particle size of the spherical particles can be measured with a microscope, more specifically with a scanning electron microscope (SEM). In one or more specific embodiments, the spherical particles have a median particle size in the range of about 1.0 to about 5 microns, such as in the range of about 1.2 to about 3.5 microns. As used herein, the term “median particle size” refers to the median cross-sectional diameter of a spherical particle. In one or more embodiments, at least 80% of the spherical particles have a median particle size in the range of 0.5 to 2.5 microns.

  In one or more embodiments, the individual crystals of the molecular sieve are in the range of about 1 to about 250 nm, such as 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110. , 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240 and 250 nm. The crystal size of the individual crystals of the molecular sieve can be measured with a microscope, more specifically with a scanning electron microscope (SEM). In certain embodiments, the individual crystals of the molecular sieve have a crystal size in the range of about 100 to about 250 nm, or about 100 to about 200 nm. In general, there is no particular limitation as far as the shape of the individual crystals of the molecular sieve is concerned. In one or more embodiments, the individual crystals of the molecular sieve are cubic, spherulitic, platelet, acicular, equiaxed, octagonal, tetragonal, hexagonal, oblique It may be, but is not limited to, tetragonal, triangular, etc., or any combination thereof.

  While not intending to be bound by theory, it is believed that in one or more embodiments, the catalyst material has a monodispersed snowball structure. As used herein, the term “monodispersed snowball” refers to a substantially spherical mass of an arrangement or collection of a number of individual molecular sieve crystals. As used herein, the term “monodispersed” means that the individual molecular sieve crystals are uniform and approximately the same size and have a crystal size in the range of about 1 to about 250 nanometers. means. Monodispersed snowballs are similar to the individual snow particles that form a snowball. In other embodiments, the catalyst material has a spherical snowball structure, wherein at least 80% of the spherical particles have a median particle size in the range of 0.5 to 2.5 microns.

  In one or more embodiments, individual crystals of molecular sieves form microaggregates, which in turn form macroaggregated snowball structures. In one or more embodiments, the microaggregates are less than 1.0 microns, such as less than 0.9 microns, less than 0.8 microns, less than 0.7 microns, less than 0.6 microns, less than 0.5 microns, Spherical snowballs having sizes in the range of less than 0.4 microns, less than 0.3 microns, less than 0.2 microns, and less than 0.1 microns, and macroaggregates are from about 0.5 microns to about 5 microns. It has a particle size in the range of microns, for example from about 1.2 microns to about 3.5 microns. The size of the microaggregates can be measured with a microscope, more specifically with a scanning electron microscope (SEM).

  In one or more embodiments, the molecular sieve includes an isomorphously substituted zeolitic framework material, wherein a portion of the silicon atoms are isomorphously substituted with a tetravalent metal. The isomorphous substituted zeolite framework material according to embodiments of the present invention can be provided as a washcoat. The isomorphously substituted zeolite framework material provides a washcoat that is generally very porous. The particle size of the isomorphous substituted zeolite framework material is generally in the range of 1-2 μm. Furthermore, although not intended to be bound by theory, it is believed that the presence of a tetravalent metal, particularly titanium, controls the zeolite crystals to produce a monodispersed snowball structure. In other words, molecular sieves include agglomerates of molecular sieve crystals that are isomorphously substituted with a tetravalent metal. As will be apparent to those skilled in the art, the particles of the molecular sieve comprising the isomorphously substituted zeolite framework material are considerably larger than the molecular sieve having a CHA structure prepared according to conventional methods known in the art. Molecular sieves prepared by such conventional methods are known to have a particle size of less than about 0.5 μm.

The monodispersed snowball structure of one or more embodiments can be more easily understood by the schematic diagram of FIG. Referring to FIG. 1, an exemplary embodiment of a catalyst material is shown. The catalyst material includes spherical particles 10 that include agglomeration of crystals 20. Spherical particles 10 have a particle size _{S p} containing from about 0.5 to about 5 microns, for example from about 1.2 to about 3.5 microns. Individual crystals of the molecular sieve 20 has a crystal size _{S c} which includes a range from about 1 to about 250 nanometers, such as about 100 to 250 nm, or such as 100 to 200 nm. In one or more embodiments, the individual crystals 20 of the molecular sieve form a microaggregate 30 which in turn forms a macroaggregated snowball structure 10. Micro aggregate 30 has a size _{S m} in the range greater than 1.0 microns below and 0 microns.

  As will be apparent to those skilled in the art, the molecular sieve crystal spherical particles are significantly different in structure from molecular sieves having a CHA structure without an aggregated snowball structure.

  The catalyst material according to embodiments of the present invention can be provided in the form of a powder or sprayed material from a separation technique such as decantation, filtration, centrifugation or spraying.

  In general, the powder or sprayed material can be molded without any other compound, for example, by appropriate compression, a molded product of a desired shape, such as a tablet, cylinder, sphere, etc. can be obtained.

  By way of example, the powder or sprayed material is mixed or coated with suitable modifiers well known in the art. By way of example, modifiers such as silica, alumina, zeolites or refractory binders (eg zirconium precursors) may be used. The powder or sprayed material may optionally form a slurry with, for example, water after mixing or coating with a suitable modifier, which may be a suitable refractory carrier, such as a flow-through honeycomb substrate carrier or wall flow. Deposited on a type honeycomb substrate carrier.

  The catalyst material according to embodiments of the present invention may also be in the form of extrudates, pellets, tablets, or any other suitable shape for use as a fixed bed of granular catalyst or as a shaped piece such as a plate, saddle, tube, etc. It can be provided in the form of particles.

SCR catalyst complex:
The ordinance, use of the NO _x reduction technologies for lightweight vehicles and heavy vehicles is obligatory. Selective catalytic reduction (SCR) of NO _x using ammonia is an efficient and dominant emission control technique for NO _x control. In an exemplary embodiment, an SCR catalyst composite is provided that has an increased ammonia storage capacity at a temperature of 400 ° C. or higher and the ability to promote ammonia storage in water. While the catalyst material of one or more embodiments can be used in any lean burn engine, including diesel engines, lean burn gasoline direct injection engines and compressed natural gas engines, in certain embodiments, the catalyst material is lean It will be used in burn gasoline direct injection (GDI) engines.

Embodiments of the present invention relate to a catalyst composite comprising an SCR catalyst material and an ammonia storage material comprising a transition metal having an oxidation number IV. This SCR catalyst composite is effective for storing ammonia at 400 ° C. or higher, and the minimum NH ₃ storage amount at 400 ° C. is 0.1 g / L. In one or more embodiments, the SCR catalyst material promotes the reaction of ammonia with nitrogen oxides to selectively form nitrogen and H ₂ O over a temperature range of 150 ° C. to 600 ° C. The material is effective for storing ammonia above 400 ° C., and the minimum NH ₃ storage at 400 ° C. is 0.1 g / L. Surprisingly, it has been found that this catalyst composite is particularly suitable as an SCR catalyst material, particularly in exhaust gas purification catalyst components.

  According to one or more embodiments, the SCR catalyst composite includes an SCR catalyst material and an ammonia storage material. In one or more embodiments, the SCR catalyst material includes one or more of molecular sieves, mixed oxides, and activated refractory metal oxide supports.

  In one or more embodiments, the SCR catalyst material includes a molecular sieve. According to one or more embodiments, the ammonia storage material includes a transition metal having an oxidation number IV. While not intending to be bound by theory, it is believed that the presence of an element having a formal oxidation number IV helps to increase ammonia storage at high temperatures. In one or more embodiments, the transition metal having an oxidation number IV may be in the form of an oxide or may be substantially embedded in the SCR catalyst material. As used herein, the term “transition metal with oxidation number IV” refers to a metal having a state with four electrons available for covalent chemical bonding at its valence (outermost electron shell). Transition metals having an oxidation number IV include germanium (Ge), cerium (Ce), and transition metals located in group 4 of the periodic table, titanium (Ti), zirconium (Zr), and hafnium (Hf). In one or more embodiments, the transition metal having an oxidation number IV is selected from Ti, Ce, Zr, Hf, Ge, and combinations thereof. In certain embodiments, the transition metal having an oxidation number IV comprises Ti.

  One or more embodiments of the present invention relate to an SCR catalyst composite that includes an SCR catalyst material and an ammonia storage material that includes a transition metal having an oxidation number of IV, wherein the SCR catalyst material and the ammonia storage material are layered. Are in an arrangement or relationship. In one or more embodiments, the ammonia storage material may take any flexible form, for example layered or homogeneously mixed with the SCR catalyst material and substantially within the same SCR catalyst material. Has been introduced. According to one or more embodiments, the ammonia storage material is dispersed as a layer over the SCR catalyst material. According to one or more embodiments, the SCR catalyst material is washcoated on the substrate, and then the ammonia storage material is washcoated as a layer over the SCR catalyst material.

  In other embodiments, the SCR catalyst material and the ammonia storage material are arranged in zones. In one or more embodiments, the SCR catalyst material and the ammonia storage material are arranged in a lateral zone and the ammonia storage material is upstream from the SCR catalyst material. As used herein, the term “laterally zoned” refers to the relative positioning of the SCR catalyst material and the ammonia storage material. “Lateral” means that the SCR catalyst material and the ammonia storage material are arranged side by side so that the ammonia storage material is upstream of the SCR catalyst material. As used herein, the terms “upstream” and “downstream” refer to relative directions according to the flow of engine exhaust gas flow from the engine to the exhaust pipe, where the engine is located upstream and the exhaust All of the pollution-reducing items such as tubes and filters and catalysts are downstream from the engine. According to one or more embodiments, the laterally zoned ammonia storage material and the SCR catalyst material may be disposed on the same or common substrate or on different substrates that are separate from each other.

  In yet another embodiment, the SCR catalyst material is ion exchanged with an ammonia storage material.

  In one or more embodiments, in a layered or zoned arrangement, the transition metal having an oxidation number IV may be present in the form of an oxide, ion-exchanged, or at the zeolite framework position. It may be isomorphously substituted. For example, in certain embodiments, the transition metal having an oxidation number IV includes titanium. In such embodiments where the transition metal having an oxidation number IV is present in the form of an oxide, an ammonia storage material comprising the transition metal having an oxidation number IV is dispersed across the support material.

Referring to FIG. 2, an exemplary embodiment of a laterally zoned system is shown. The SCR catalyst composite 200 is shown in a laterally zoned arrangement, where an ammonia storage material 210 is placed upstream of the SCR catalyst material 220 on a common substrate 230. The substrate 230 has an inlet end 240 and an outlet end 250 that define an axial length L. In one or more embodiments, the substrate 230 generally has a plurality of honeycomb substrate channels 260, of which only one channel is shown in cross-section for clarity. The ammonia storage material 210 extends from the inlet end 240 of the base material 230 without reaching the entire axial length L of the base material 230. The length of the ammonia storage material 210 is shown as the first zone 210a in FIG. The ammonia storage material 210 includes a transition metal having an oxidation number IV. The SCR catalyst material 220 extends from the outlet end 250 of the base material 230 without reaching the entire axial length L of the base material 230. The length of the SCR catalyst material 220 is shown as the second zone 220a in FIG. The SCR catalyst material 220 promotes the reaction between ammonia and nitrogen oxide to selectively form nitrogen and H ₂ O over a temperature range of 150 ° C. to 600 ° C., and the ammonia storage material 210 is 400 ° C. or higher. Effective for storing ammonia, the minimum NH ₃ storage is 0.00001 g / L.

  It should be understood that the lengths of the first zone 210a and the second zone 220a can be varied. In one or more embodiments, the lengths of the first zone 210a and the second zone 220a may be equal. In other embodiments, the first zone may be 20%, 25%, 35% or 40%, 60%, 65%, 75% or 80% of the substrate length L, where: The second zone is the remaining part of the length L of the substrate each time.

Referring to FIG. 3, another embodiment of a laterally zoned SCR catalyst composite 110 is shown. The illustrated SCR catalyst composite 110 is shown in a laterally zoned arrangement, where ammonia storage material 118 is located upstream of SCR catalyst material 120 on separate substrates 112 and 113. Has been. The ammonia storage material 118 is deposited on the substrate 112 and the SCR catalyst material is deposited on a separate substrate 113. The substrates 112 and 113 may be composed of the same material or different materials. The substrate 112 has an inlet end 122a and an outlet end 124a that define an axial length L1. The base material 113 has an inlet end 122b and an outlet end 124b that define an axial length L2. In one or more embodiments, substrates 112 and 113 generally have a plurality of channels 114 of a honeycomb substrate, of which only one channel is shown in cross section for clarity. The ammonia storage material 118 extends from the inlet end 122a of the substrate 112 to the outlet end 124a through the entire axial length L1 of the substrate 112. The length of the ammonia storage material 118 is shown as the first zone 118a in FIG. The ammonia storage material 118 includes a transition metal having an oxidation number IV. The SCR catalyst material 120 extends from the outlet end 124b of the base material 113 to the inlet end 122b through the entire axial length L2 of the base material 113. The SCR catalyst material 120 defines a second zone 120a. The length of the SCR catalyst material is shown as the second zone 20b in FIG. The SCR catalyst material 120 promotes the reaction between ammonia and nitrogen oxide to selectively form nitrogen and H ₂ O over a temperature range of 150 ° C. to 600 ° C., and the ammonia storage material 118 is 400 ° C. or higher. Effective for storing ammonia, the minimum NH ₃ storage is 0.00001 g / L. The length of zones 118a and 120a can be varied as described with respect to FIG.

  In one or more embodiments, an SCR catalyst composite comprising an ammonia storage material and an SCR catalyst material is coated on a flow-through or wall flow filter. 4A and 4B show a wall flow type filter substrate 35 having a plurality of passages 52. FIG. The passage is surrounded in a tubular shape by the inner wall 53 of the filter substrate. The substrate has an inlet end 54 and an outlet end 56. The passages are alternately closed at the inlet end by an inlet plug 58 and at the outlet end by an outlet plug 60 to form opposing checkerboard patterns at the inlet 54 and outlet 56. A gas stream 62 enters through the unblocked channel inlet 64 and is stopped by the outlet plug 60 and diffuses through the channel wall 53 (which is porous) toward the outlet side 66. The gas cannot return to the inlet side of the wall because of the inlet plug 58.

  In one or more embodiments, the wall flow filter substrate is a ceramic-like material such as cordierite, alpha-alumina, silicon carbide, silicon nitride, zirconia, mullite, spodumene, alumina-silica-magnesia or zirconium silicate, or Consists of porous and refractory metal. In other embodiments, the wall flow-type substrate is formed from a ceramic fiber composite material. In certain embodiments, the wall flow type substrate is formed from cordierite and silicon carbide. Such materials can withstand the environments generated in the treatment of exhaust streams, particularly high temperatures.

In one or more embodiments, the wall flow type substrate comprises a thin porous walled honeycomb monolith through which fluid flow passes without significantly increasing the back pressure or pressure across the article. Typically, the presence of clean wall flow type articles will result in back pressures from 1 inch of water column to 10 psig. The ceramic wall flow type substrate used in this system is formed of a material having a porosity of at least 50% (eg 50-75%) having an average pore size of at least 5 microns (eg 5-30 microns). . In one or more embodiments, the substrate has a porosity of at least 55% and an average pore size of at least 10 microns. When substrates having these porosities and these average pore sizes are coated with the techniques described below, sufficient levels of catalyst composition on the substrate to achieve excellent NO _x conversion efficiency. Can be loaded. These substrates can still maintain sufficient exhaust flow properties, i.e. acceptable back pressure, despite being loaded with the SCR catalyst. United States Patent No. 4,329,162 (United States Patent No. 4,329,162) is hereby incorporated by reference with respect to the disclosure of suitable wall flow substrates.

  Typical wall flow filters used commercially are formed with a lower wall porosity, for example about 35-50%, than the wall flow filters utilized in the present invention. In general, the pore size distribution of commercially available wall flow filters is typically very broad with an average pore size of less than 17 microns.

  Porous wall flow filters used in one or more embodiments are catalyzed by having the element walls have or include one or more SCR catalyst materials thereon. The catalytic material may be present only on the inlet side of the element wall, only on the outlet side, both on the inlet side and on the outlet side, or the wall itself may consist of all or part of the catalytic material. . The invention includes the use of one or more layers of catalytic material on the inlet and / or outlet walls of the element and the use of a combination of one or more layers of catalytic material.

  To coat a wall flow type substrate with one or more embodiments of the SCR catalyst composite, the substrate is perpendicular to a portion of the catalyst slurry so that the top of the substrate is directly above the surface of the slurry. Immerse in the direction. In this way, the slurry contacts the inlet face of each honeycomb wall, but is prevented from contacting the outlet face of each wall. The sample is left in the slurry for about 30 seconds. The substrate is transferred from the slurry and the removal of excess slurry from the wall flow type substrate first drains the slurry from the channel, then blows compressed air (relative to the direction of slurry infiltration) and then the slurry This is done by drawing a vacuum from the direction of penetration. By using this technique, the catalyst slurry penetrates the walls of the substrate, but the pores are not occluded to the extent that excessive back pressure is generated on the finished substrate. The term “penetrating” as used herein, when used to describe the dispersion of a catalyst slurry on a substrate, means that the catalyst composition is dispersed throughout the walls of the substrate. To do.

  The coated substrate is typically dried at about 100 ° C. and fired at higher temperatures (eg, 300-450 ° C.). After calcination, the catalyst loading can be determined by calculating the coated and uncoated mass of the substrate. As will be apparent to those skilled in the art, the catalyst loading can be varied by changing the solids content of the coating slurry. Alternatively, the substrate may be repeatedly dipped into the coating slurry, followed by removal of excess slurry as described above.

  According to one or more embodiments, the ammonia storage material of the SCR catalyst composite is dispersed in the SCR catalyst material. Thus, according to an embodiment of the present invention, the SCR catalyst material comprises a molecular sieve having a skeleton of silicon (Si) ions and aluminum (Al) ions, and optionally phosphorus (P) ions, where silicon atoms Is isomorphously substituted with an ammonia storage material comprising a transition metal having an oxidation number IV.

In one or more embodiments, an ammonia oxidation (AMO _x ) catalyst may be provided downstream of the SCR catalyst complex to remove any ammonia slipped from the exhaust gas treatment system. In certain embodiments, the AMOx catalyst may include a platinum group metal such as platinum, palladium, rhodium, or combinations thereof.

AMO _x and / or one or more SCR catalyst materials may be coated on a flow-through or wall-flow filter. If a wall flow type substrate is utilized, the resulting system can remove particulate matter along with gaseous contaminants. The wall flow filter substrate may be composed of materials well known in the art such as cordierite, aluminum titanate or silicon carbide. The loading of the catalyst composition on the wall flow substrate depends on the substrate properties such as porosity and wall thickness and is typically lower than the loading on the flow through substrate. I want you to understand.

  In one or more embodiments, a portion of the silicon atoms are isomorphously substituted with a transition metal having an oxidation number IV. In other words, a portion of the silicon atoms in the zeolite framework material is replaced with a transition metal having an oxidation number IV. Such isomorphous substitution does not significantly change the crystal structure of the zeolite framework material.

Typically, NH ₃ storage over zeolite SCR catalysts needs to be suppressed to obtain a faster NO _x conversion response for highly dynamic engine operation. While not intending to be bound by theory, prior art SCR catalysts provide the required high temperature NH ₃ storage, weak NH ₃ physisorption into the zeolite voids, or blends of unused exchange sites. Achieving this by relying on Steed acidity is considered impossible due to the presence of relatively large amounts of competing water vapor.

Therefore, realizing a secondary functional site that can perform NH ₃ storage at high temperatures and can distinguish between NH ₃ and H ₂ O for storage, ie, utilizing Lewis acidity There is a need. Since NH ₃ is inherently nucleophilic (or more generally basic), it is believed that Lewis acidity can provide an additional means for NH ₃ storage. Accordingly, transition metals with different oxidation numbers can tunably provide Lewis acidity strength. In general, the higher the acid number of the transition metal, the stronger the Lewis acidity is expected. Thus, transition metals having an oxidation number IV are intended to provide catalytic materials that can store NH ₃ at relatively high temperatures.

In one or more embodiments, the SCR catalyst material comprises a molecular sieve comprising a SiO ₄ / AlO ₄ tetrahedron. In one or more embodiments, the SCR catalyst material is isomorphously replaced with an ammonia storage material. In such an embodiment, the SCR catalyst material comprises a MO ₄ / SiO ₄ / AlO ₄ tetrahedron (where M is a transition metal having an oxidation number IV) and is bound by a common oxygen atom. To form a three-dimensional network. An isomorphously substituted transition metal having an oxidation number IV is embedded in the molecular sieve as tetrahedral atoms (MO ₄ ). The isomorphously substituted tetrahedral unit then forms a molecular sieve skeleton with the silicon and aluminum tetrahedral units. In a particular embodiment, the transition metal having an oxidation number IV comprises titanium and the SCR catalyst material then comprises a TiO ₄ / SiO ₄ / AlO ₄ tetrahedron.

In other embodiments, the SCR catalyst material comprises a molecular sieve comprising a SiO ₄ / AlO ₄ / PO ₄ tetrahedron. In one or more embodiments, the SCR catalyst material is isomorphously replaced with an ammonia storage material. In such embodiments, the SCR catalyst material comprises a MO ₄ / SiO ₄ / AlO ₄ / PO ₄ tetrahedron (where M is a transition metal having an oxidation number IV) and a common oxygen atom To form a three-dimensional network. An isomorphously substituted transition metal having an oxidation number IV is embedded in the molecular sieve as tetrahedral atoms (MO ₄ ). The isomorphously substituted tetrahedral units together with the silicon, aluminum and phosphorus tetrahedral units form the molecular sieve framework. In a particular embodiment, the transition metal having an oxidation number IV comprises titanium and the SCR catalyst material comprises a TiO ₄ / SiO ₄ / AlO ₄ / PO ₄ tetrahedron.

The isomorphously substituted molecular sieve of one or more embodiments is formed by a rigid network of MO ₄ / (SiO ₄ ) / AlO ₄ tetrahedra (where M is a metal having an oxidation number IV). It is mainly distinguished according to the shape of the void.

  In one or more embodiments, the molecular sieve of the SCR catalyst material has a structural type selected from any of those previously described. In one or more specific embodiments, the molecular sieve is MFI, BEA, AEI, AFT, AFX, CHA, EAB, EMT, ERI, FAU, GME, JSR, KFI, LEV, LTL, LTN, MOZ, MSO, It has a structural type selected from MWW, OFF, SAS, SAT, SAV, SBS, SBT, SFW, SSF, SZR, TSC, WEN and combinations thereof. In another particular embodiment, the molecular material has a structural type selected from the group consisting of MFI, BEA, CHA, AEI, AFX, ERI, KFI, LEV and combinations thereof. In a very particular embodiment, the molecular sieve has a structural type selected from CHA, AEI and AFX. In a very specific embodiment, the molecular sieve comprises SSZ-13, SSZ-39 or SAPO-34. In another very specific embodiment, the molecular sieve is of the aluminosilicate zeolite type and has an AEI structural type, such as SSZ-39. According to one or more embodiments, defining a molecular sieve by its structural type includes structural types that have the same structural type and any skeletal material of any identical structural type, such as SAPO, ALPO, and MeAPO materials. Should be understood as intended.

  The silica / alumina ratio of the molecular sieve may vary over a wide range. In one or more embodiments, the molecular sieve has a silica / alumina molar ratio (SAR) in the range of 2 to 300, such as 5 to 250; 5 to 200; 5 to 100; and 5 to 50. In one or more specific embodiments, the molecular sieve is 10-200, 10-100, 10-75, 10-60 and 10-50; 15-100, 15-75, 15-60 and 15-50; Silica / alumina molar ratio (SAR) in the range of 20-100, 20-75, 20-60 and 20-50.

  The transition metal / alumina ratio with oxidation number IV may vary over a very wide range. In one or more embodiments, the transition metal / alumina ratio having an oxidation number IV is in the range of 0.001 to 10000, such as 0.001 to 10000, 0.001 to 1000, and 0.01 to 10. . In other embodiments, the transition metal / alumina ratio having oxidation number IV is in the range of 0.01-10, such as 0.01-10, 0.01-5, 0.01-2, and 0.01-1. It is in the range. In certain embodiments, the transition metal / alumina ratio having oxidation number IV is in the range of 0.01-2.

  In certain embodiments, the transition metal having an oxidation number IV comprises titanium and the titania / alumina ratio is in the range of 0.001 to 10,000, such as 0.001 to 10000, 0.001 to 1000, and 0.01 to It is in a range such as 10. In other embodiments, the titania / alumina ratio is in the range of 0.01 to 10, such as 0.01 to 10, 0.01 to 5, 0.01 to 2, and 0.01 to 1. In certain embodiments, the titania / alumina ratio is in the range of 0.01-2. In a very specific embodiment, the titanium / alumina ratio is about 1.

  The transition metal ratio with silica / oxidation number IV may vary over a wide range. Note that this ratio is an atomic ratio, not a molar ratio. In one or more embodiments, the transition metal ratio having silica / oxidation number IV is in the range of 1-100, such as 1-50, 1-30, 1-25, 1-20, 5-20 and 10-20. It is in the range. In a particular embodiment, the transition metal ratio with silica / oxidation number IV is about 15. In one or more embodiments, the transition metal having an oxidation number IV comprises titanium and the silica / titania ratio is in the range of 1-100, such as 1-50, 1-30, 1-25, 1-20, It exists in the range of 5-20 and 10-20. In certain embodiments, the silica / titania ratio is about 15.

  In order to promote nitrogen oxide SCR, in one or more embodiments, a suitable metal is exchanged into the SCR catalyst material. According to one or more embodiments, the SCR catalyst material is promoted with a metal selected from Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag, and combinations thereof. In certain embodiments, the SCR catalyst material is promoted with Cu, Fe, and combinations thereof.

  The promoter metal content of the SCR catalyst material, calculated as oxide, is reported to be at least about 0.1 wt% in one or more embodiments and free of volatiles. In a particular embodiment, the cocatalyst metal comprises Cu and the Cu content calculated as CuO is based on the total mass of calcined SCR catalyst material reported on the basis that it contains no volatiles each time. , In the range up to about 10% by weight, for example 9, 8, 7, 6, 5, 4, 3, 2 and 1% by weight. In certain embodiments, the Cu content calculated as CuO is in the range of about 2 to about 5 weight percent.

  While not intending to be bound by theory, when the SCR catalyst material is isomorphously substituted with an ammonia storage material that includes a transition metal having an oxidation number IV, the transition metal having an oxidation number IV is defined as a tetrahedral atom. It is embedded in the molecular sieve skeleton and is considered to be able to bind closely to the active promoter metal center structurally and electronically. In one or more embodiments, the promoter metal may be ion exchanged into the SCR catalyst. In certain embodiments, copper may be ion exchanged into the SCR catalyst material. This metal may be replaced after preparation or manufacture of the SCR catalyst.

According to one or more embodiments, the SCR catalyst material comprises a mixed oxide. As used herein, the term “mixed oxide” refers to an oxide that includes a cation of one or more chemical elements or a cation of a single element in several oxidation numbers. In one or more embodiments, the mixed oxide is Fe / titania (eg, FeTiO ₃ ), Fe / alumina (eg, FeAl ₂ O ₃ ), Mg / titania (eg, MgTiO ₃ ), Mg / alumina (eg, MgAl ₂ O). ₃ ), Mn / alumina, Mn / titania (eg MnO _x / TiO ₂ ) (eg MnO _x / Al ₂ O ₃ ), Cu / titania (eg CuTiO ₃ ), Ce / Zr (eg CeZrO ₂ ), Ti / Zr (Eg TiZrO ₂ ), vanadia / titania (eg V ₂ O ₅ / TiO ₂ ) and mixtures thereof. In certain embodiments, the mixed oxide comprises vanadia / titania. Vanadia / titania oxide can be activated or stabilized with tungsten (eg, WO ₃ ) to provide V ₂ O ₅ / TiO ₂ / WO ₃ . In one or more embodiments, the SCR catalyst material comprises titania with vanadium dispersed therein. Vanadia may be dispersed at concentrations ranging from 1 to 10% by weight, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10% by weight. In certain embodiments, Vanadia is activated or stabilized by tungsten (WO ₃ ). Tungsten may be dispersed at concentrations ranging from 0.5 to 10% by weight, for example 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10% by weight. All percentages are based on oxides.

According to one or more embodiments, the SCR catalyst material includes a refractory metal oxide support material. As used herein, the terms “refractory metal oxide support” and “support” refer to a high surface area base material carrying additional compounds or elements. The carrier particles have pores larger than 20 mm and a wide pore distribution. As defined herein, such metal oxide supports exclude molecular sieves, specifically zeolites. In certain embodiments, a high surface area refractory metal oxide support that typically exhibits a BET surface area of greater than 60 grams per square meter (“m ² / g”) and frequently up to about 200 m ² / g, For example, an alumina support material also referred to as “gamma alumina” or “activated alumina” can be utilized. Such activated alumina is usually a mixture of the γ and δ phases of alumina, but may contain significant amounts of η, κ and θ-alumina phases. Refractory metal oxides other than activated alumina may be used as at least some supports for the catalyst components in a given catalyst. For example, bulk ceria, zirconia, α-alumina and other materials are known for such applications. Many of these materials have the disadvantage of having a significantly lower BEI surface area than activated alumina, which is easily offset by greater durability or performance enhancement of the resulting catalyst. “BET surface area” has the usual meaning of referring to the Brunauer-Emmett-Teller method of measuring surface area by N ₂ adsorption. The pore diameter and pore volume can also be measured using a BET type N ₂ adsorption or desorption experiment.

  One or more embodiments of the present invention include alumina, ceria, zirconia, silica, titania, silica-alumina, zirconia-alumina, titania-alumina, lantana-alumina, lantana-zirconia-alumina, barrier-alumina, barrier-lantana. High surface area comprising an active compound selected from the group consisting of alumina, barrier-lantana-neodymia-alumina, alumina-chromia, alumina-ceria, zirconia-silica, titania-silica, or zirconia-titania, and combinations thereof Include refractory metal oxide support. In one or more embodiments, the activated refractory metal oxide support is a metal selected from the group consisting of Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag, and combinations thereof. Exchanged.

SCR activity:
In one or more embodiments, the selective catalytic reduction material comprising spherical particles comprising agglomerates of molecular sieve crystals is at least 50% as measured at 80000 h ⁻¹ space velocity (Gas Hourly Space Velocity). indicating the deterioration NO _x conversion at 200 ° C.. In certain embodiments, the material exhibits a degraded NO _x conversion at 450 ° C. of at least 70%, measured at a space velocity of 80000 h ⁻¹ . More specifically, in a gas mixture of NO _x 500 ppm, NH ₃ 500 ppm, O ₂ 10%, H ₂ O 5%, N ₂ residue, a space of 80000 h ⁻¹ under steady state conditions at maximum NH ₃ slip conditions. Degraded NO _x conversion at 200 ° C is at least 55%, measured at gas velocity (gas hourly volume-based space velocity) per unit volume of catalyst, and at least at 450 ° C 75%, and even more specifically, the degraded NO _x conversion at 200 ° C. is at least 60% and at 450 ° C. is at least 80%. The core is hydrothermally degraded in a tubular furnace in a gas stream containing 10% H ₂ O, 10% O ₂ and N ₂ residue for 5 hours at 750 ° C. at a space velocity of 4,000 h ^−1. I let you.

  The measurement of SCR activity is specified in the literature (see eg PCT Application Publication No. WO 2008/106519).

Moreover, according to one or more embodiments, the catalyst material is effective in reducing N ₂ O production.

NO ⁺ formation and ammonia storage:
Furthermore, according to one or more embodiments, particularly when the molecular sieve comprises an isomorphous substituted zeolitic framework material of silicon and aluminum atoms, wherein a portion of the silicon atoms are isomorphously substituted with a tetravalent metal. This material is effective in promoting the formation of NO ⁺ . Without intending to be bound by theory, it is believed that the d6r unit of the zeolite framework material is an important factor that facilitates NO ⁺ formation. This is because the d6r unit promotes the movement / hopping of a short distance promoter metal (eg Cu) between the two six-membered mirror mirrors to provide NO ⁺ (which is also provided by the d6r unit). This creates a suitable vacancy for a stable coordination environment).

Moreover, according to one or more embodiments, particularly when the SCR catalyst complex includes an SCR catalyst material and an ammonia storage material that includes a transition metal having an oxidation number IV, the SCR catalyst material is oxidized with ammonia and nitrogen. Promotes reaction with materials to selectively form nitrogen and H ₂ O over a temperature range of 150 ° C. to 600 ° C., and an ammonia storage material is effective for storing ammonia at temperatures of 400 ° C. or higher. The minimum ammonia storage amount is 0.00001 g / L. In one or more embodiments, the oxygen content of the exhaust gas stream is 0-30% and the moisture content is 1-20%. The SCR catalyst complex according to one or more embodiments adsorbs NH ₃ even in the presence of H ₂ O. The SCR catalyst composite of one or more embodiments exhibits a higher hot ammonia storage capacity than the reference SCR catalyst material and catalyst composite.

Water, which also has a lone pair as a nucleophile, is the largest competitor for ammonia storage by Bronsted acid sites. As can be efficiently utilized by NO _x generated in lean cycle lean GDI engine, increasing the amount of NH ₃ is chemically adsorbed than NH ₃ amount of physically adsorbed is important. Without intending to be bound by theory, it is believed that the Lewis acidity of a transition metal having an oxidation number of IV increases the ability of the SCR catalyst complex to chemically adsorb ammonia. Accordingly, the SCR catalyst composite according to one or more embodiments has improved ammonia storage capacity at a temperature of about 400 ° C. or higher.

Base material:
In one or more embodiments, the catalyst material can be applied to the substrate as a washcoat. As used herein, the term “substrate” refers to a monolithic material on which a catalyst is placed, typically in the form of a washcoat. The washcoat is formed by preparing a slurry containing specific solids (eg, 30-90% by weight) of the catalyst in a liquid vehicle, which is then coated onto the substrate and dried to produce a washcoat layer I will provide a.

  As used herein, the term “washcoat” has its usual meaning in the art of thin and tacky coatings of catalyst materials or other materials applied to substrate materials such as honeycomb-type support members. However, it is sufficiently porous to pass the gas stream to be treated.

  In one or more embodiments, the substrate is a ceramic or metal having a honeycomb structure. Any suitable substrate, for example of the type having a narrow and parallel gas flow path, through which the flow path extends through the inlet or outlet surface of the substrate, allowing fluid flow therethrough A monolithic substrate may be used. The definition of the passage, which is an essentially straight path from the fluid inlet to the fluid outlet, is made by the wall on which the catalytic material is coated as a washcoat so that the gas flowing through this passage is in contact with the catalytic material. The flow path of the monolithic substrate may be thin-walled channels, which are of any suitable cross-sectional shape and size such as trapezoidal, rectangular, square, sinusoidal, hexagonal, elliptical, circular, etc. Good. Such a structure may include from about 60 to about 900 or more gas inlet openings (ie cells) per square inch of cross-section.

  The ceramic substrate can be any suitable refractory material such as cordierite, cordierite-α-alumina, silicon nitride, zircon-mullite, spodumene, alumina-silica-magnesia, zircon silicate, silimanite, magnesium silicate, zircon, It may be composed of petalite, α-alumina, aluminosilicate, or the like.

  Substrates useful for the catalyst of embodiments of the present invention may actually be made of metal and may be composed of one or more metals or metal alloys. The metal substrate may be used in various shapes such as pellets, corrugated sheets or monolithic forms. Specific examples of metallic substrates include heat resistant base metal alloys, particularly those in which iron is a substantial or major component. Such alloys may contain one or more of nickel, chromium and aluminum, and the sum of these metals is preferably at least about 15% by weight of the alloy, for example about 10-25% by weight. Of chromium, about 1-8 wt.% Aluminum and about 0-20 wt.% Nickel.

Preparation of catalyst and catalyst material:
Synthesis of conventional CHA-type molecular sieves Molecular sieves having a CHA structure can be prepared by various techniques known in the art, such as United States Patent Nos. 4,544,538 (Zones). ) And United States Patent No. 6,709,644 (Zones), which are incorporated herein by reference in their entirety.

Optional NH ₄ exchange to form NH ₄ -chabasite:
Optionally, the alkali metal zeolite obtained by NH ₄ exchanged NH ₄ - to form a chabazite. This NH ₄ -ion exchange can be accomplished by various techniques known in the art, such as Bleken, F .; Bjorgen, M .; Palumbo, L .; Bordiga, S .; Swell, S .; Lillerud, K .; -P. And Olsbye, U .; Can be performed according to Topics in Catalysis 52, (2009), 218-228

Synthesis of Snowball Type Molecular Sieve A molecular sieve with moisture in the form of a snowball type can be prepared from adamantyltrimethylammonium hydroxide (ADAOH), aqueous sodium hydroxide, aluminum isopropoxide powder and colloidal silica.

Synthesis of Isomorphous Substituted Zeolite Framework Material According to one or more embodiments, a method of synthesizing a selective catalytic reduction catalyst material comprising an isomorphously substituted zeolite framework material is provided. In particular, the catalyst material includes a zeolite framework material of silicon atoms and aluminum atoms, wherein a part of the silicon atoms is isomorphously substituted with a tetravalent metal.

In general, the sodium form of isomorphous substituted zeolite framework material is 0.03Al ₂ O ₃ : SiO ₂ : 0.07TiO ₂ : 0.06Na ₂ O: 0.08ATMAOH: 2.33H ₂ O by autoclave hydrothermal synthesis. It can be prepared from a gel composition. The product is recovered by filtration and the template is removed by calcination. The final crystalline material can be characterized by X-ray diffraction studies.

Form H can be prepared by calcination of the ammonia form obtained through two NH ₄ NO ₃ exchanges with the sodium form. The Ti level remains unchanged / stable throughout the NH ₄ NO ₃ exchange process.

Copper promoted isomorphous substituted zeolite frameworks can be prepared by ion exchange with H-form and Cu (OAc) ₂ to achieve the desired amount of promoter metal.

Synthesis of isomorphically substituted molecular sieves According to one or more embodiments, synthesis of an SCR catalyst complex comprising an SCR catalyst material comprising a molecular sieve that is isomorphously substituted with an ammonia storage material comprising a transition metal having an oxidation number of IV. Law is provided. In particular, the SCR catalyst composite includes an SCR catalyst material having a zeolitic framework material of silicon and aluminum atoms, wherein a portion of the silicon atoms are isomorphously substituted with a transition metal having an oxidation number IV of an ammonia storage material. .

In general, the sodium form of isomorphously substituted molecular sieves is from a gel composition of 0.03Al ₂ O ₃ : SiO ₂ : 0.07TiO ₂ : 0.06Na ₂ O: 0.08ATMAOH: 2.33H ₂ O. It can be prepared by autoclave hydrothermal synthesis. The product is recovered by filtration and the template is removed by calcination. The final crystalline material can be characterized by X-ray diffraction studies.

Form H can be prepared by calcination of the ammonia form obtained through two NH ₄ NO ₃ exchanges with the sodium form. The Ti level remains unchanged / stable throughout the NH ₄ NO ₃ exchange process.

Copper-promoted isomorphous molecular sieves can be prepared by ion exchange with H-form and Cu (OAc) ₂ to achieve the desired amount of promoter metal.

NO _x reduction method and exhaust gas treatment system:
In general, the above zeolitic materials can be used as molecular sieves, adsorbents, catalysts, catalyst supports or their binders. In one or more embodiments, this material is used as a catalyst.

  An additional aspect of the present invention relates to a method of catalyzing a chemical reaction using spherical particles including agglomerates of molecular sieve crystals according to embodiments of the present invention as a catalytically active material.

  Another aspect of the present invention relates to a method for catalyzing a chemical reaction using a zeolite framework material isomorphously substituted with a tetravalent metal as a catalytically active material according to an embodiment of the present invention.

  A further aspect of the present invention catalyzes a chemical reaction using as a catalytically active material an SCR catalyst complex comprising an SCR catalyst material and an ammonia storage material comprising a transition metal having an oxidation number IV according to an embodiment of the present invention. Regarding the method.

Among other things, the catalyst materials and catalyst composites can be used as catalysts for selective reduction (SCR) of nitrogen oxides (NO _x ); NH ₃ oxidation, especially NH ₃ slip in diesel systems For application in oxidation reactions, in certain embodiments, additional noble metal components (eg, Pd, Pt) are added to the spherical particles, including agglomerates of molecular sieve crystals.

One or more embodiments provide a method for selectively reducing nitrogen oxides (NO _x ). In one or more embodiments, the method includes contacting an exhaust gas stream containing NO _x with the catalyst material or catalyst composite of one or more embodiments. In particular, the selective catalytic reduction catalyst material comprises spherical particles comprising an aggregate of molecular sieve crystals, the spherical particles having a median particle size in the range of about 0.5 to about 5 microns (an embodiment of the present invention). The selective reduction of nitrogen oxides using the catalytically active material is carried out in the presence of ammonia or urea.

  Ammonia is the reducing agent selected for stationary power plants, while urea is the reducing agent selected for mobile SCR systems. Typically, an SCR system is incorporated into a vehicle exhaust gas treatment system and typically also includes the following major components: including spherical particles containing agglomerates of molecular sieve crystals. A selective catalytic reduction material wherein the spherical particles have a median particle size in the range of about 0.5 to about 5 microns according to an embodiment of the present invention; a urea storage tank; a urea pump; a urea dosing system; a urea injector / nozzle; Each control unit.

  In other embodiments, the SCR catalyst composite according to one or more embodiments is used as an SCR catalyst in an exhaust gas treatment system for a lean burn gasoline direct injection engine. In such a case, the SCR catalyst composite according to one or more embodiments functions as a passive ammonia-SCR catalyst and can effectively store ammonia at a temperature of 400 ° C. or higher.

  The term “stream” as used herein refers broadly to any combination of flowing gases that may contain solid or liquid particulate matter. The term "gas stream" or "exhaust gas stream" refers to a stream of gaseous components that may contain non-gaseous components carried together, such as droplets, solid particles, etc. means. Lean burn engine exhaust gas streams typically contain combustion products, incomplete combustion products, nitrogen oxides, combustible and / or carbonaceous particulate matter (soot) and unreacted oxygen and nitrogen. In addition.

The term nitrogen oxide, or NO _x , used in connection with embodiments of the present invention refers to nitrogen oxides, particularly dinitrogen monoxide (N ₂ O), nitric oxide (NO), dinitrogen trioxide. (N ₂ O ₃ ), nitrogen dioxide (NO ₂ ), dinitrogen tetroxide (N ₂ O ₄ ), dinitrogen pentoxide (N ₂ O ₅ ), and nitrogen peroxide (NO ₃ ) are shown.

  A further aspect of the invention relates to an exhaust gas treatment system. In one or more embodiments, the exhaust gas treatment system includes a reducing agent, such as ammonia, urea and / or hydrocarbons, and in certain embodiments, an exhaust gas stream optionally containing ammonia and / or urea, and a molecular sieve. And a selective catalytic reduction material comprising spherical particles comprising agglomerates of crystals, the spherical particles having a median particle size in the range of about 0.5 to about 5 microns. This catalyst material is effective in decomposing at least a portion of the ammonia in the exhaust gas stream.

  In one or more embodiments, the SCR catalyst material may be disposed on a substrate, such as a soot filter. The soot filter may be upstream or downstream of the SCR catalyst material, with or without catalyzing. In one or more embodiments, the system may further include a diesel oxidation catalyst. In certain embodiments, the diesel oxidation catalyst is located upstream of the SCR catalyst material. In other specific embodiments, the diesel oxidation catalyst and the catalyzed soot filter are upstream from the SCR catalyst material.

In certain embodiments, the exhaust is carried from the engine to a location downstream of the exhaust system and in more specific embodiments contains NO _x , in which case a reducing agent is added and has the added reducing agent. The exhaust gas stream is conveyed to the SCR catalyst material.

  For example, catalyzed soot filters, diesel oxidation catalysts and reducing agents are described in WO 2008/106519 (WO 2008/106519), which is incorporated herein by reference. In certain embodiments, the soot filter is a channel that allows a gas stream entering the channel from one direction (inlet direction) to exit from the channel through the channel wall in the other direction (outlet direction). Including a wall flow type substrate in which are alternately shielded.

Ammonia oxidation (AMO _x ) catalyst can be provided downstream of the SCR catalyst material or catalyst composite of one or more embodiments to remove slipped ammonia from the system. In certain embodiments, the AMO _x catalyst may comprise a platinum group metal such as platinum, palladium, rhodium, or combinations thereof.

Such AMO _x catalysts are useful in exhaust gas treatment systems that include SCR catalysts. As described in United States Patent No. 5,516,497 (incorporated herein by reference in its entirety), assigned to the assignee of the present application, A gas stream containing nitrogen oxides and ammonia can be passed sequentially through the first and second catalysts, wherein the first catalyst is convenient for the reduction of nitrogen oxides and the second The catalyst is advantageous for the oxidation or other decomposition of excess ammonia. As described in US Pat. No. 5,516,497, the first catalyst may be an SCR catalyst containing zeolite and the second catalyst is an AMO _x catalyst containing zeolite. It's okay.

The AMO _x and / or SCR catalyst composition may be coated on a flow-through or wall flow filter. If a wall flow type substrate is utilized, the resulting system can remove particulate matter along with gaseous contaminants. The wall flow filter substrate may be composed of materials well known in the art such as cordierite, aluminum titanate or silicon carbide. The loading of the catalyst composition on the wall flow substrate depends on the substrate properties such as porosity and wall thickness and is typically lower than the loading on the flow through substrate. I want you to understand.

  The invention will now be described by reference to the following examples. Before describing some exemplary embodiments of the present invention, it is to be understood that the present invention is not limited to the details of construction or process steps set forth in the following description. The invention is capable of other embodiments and of being practiced or carried out in various ways.

Examples Comparative Example 1-Preparation of catalyst composition and catalyst article Crystallization of chabasite, separation of chabasite products using CuCHA powder catalyst with ADAOH (trimethyl-1-adamantyl ammonium hydroxide) containing synthetic gel Prepared by removing the organic template (ADAOH) by drying and baking. Water, ADAOH solution and aqueous sodium hydroxide solution were added into the make-up tank and mixed for several minutes. The aluminum source was then added in 3-5 minutes. The colloidal silica was then added over 5 minutes with stirring. Mixing was continued for another 30 minutes to obtain a viscous gel of uniform composition. The gel was transferred to an autoclave. The autoclave was heated to 170 ° C. and crystallization was continued for 18 hours while maintaining stirring. The reactor was cooled to <50 ° C. and vented to atmospheric pressure before removal. After hydrothermal crystallization, the pH of the resulting suspension was 11.5. The suspension was mixed with deionized water and filtered through a porcelain suction filter. The wet product was then heated in air to a temperature of 120 ° C. for 4 hours. The dried product was then further calcined at 600 ° C. for 5 hours in air so that the template was removed and the C content was less than 0.1% by weight.

  As can be observed in the SEM image of the crystalline form of FIG. 5, as-synthesized material (Comparative Example 1), as identified by SEM analysis (secondary electron image) at a magnification of 5000 ×, Does not have an aggregated form.

  At that time, the calcined product was in an ion-exchangeable state with Cu to obtain a metal-containing catalyst.

  The ion exchange reaction between Na-type CHA and copper ions was performed by stirring the slurry at about 60 ° C. for about 1 hour. The resulting mixture was then filtered to obtain a filter cake, which was washed in three portions with deionized water until the filtrate was clear and colorless, and the washed sample was dried.

The resulting CuCHA catalyst contained CuO in the range of about 3 to 3.5% by weight as measured by ICP analysis. A CuCHA slurry was prepared to 40% target solids. The slurry was crushed and a zirconium acetate binder (containing 30% ZrO ₂ ) dissolved in diluted acetic acid was added to the slurry with stirring.

This slurry was coated onto 1 "Dx3" L cellular ceramic cores having a cell density of 400 cpsi (cells per square inch) and a wall thickness of 6.5 mils. The coated core was dried at 110 ° C. for 3 hours and baked at about 400 ° C. for 1 hour. By repeating the coating process once, a target washcoat loading in the range of 2-3 g / in ³ was obtained.

Example 2
An agglomerated (snowball) CHA material of the present invention was prepared using the same raw materials as in Comparative Example 1 except that water was additionally added. The gel make-down procedure was also the same as in Comparative Example 1. The autoclave was heated to 160 ° C. and crystallization was continued for 30 hours while maintaining stirring. The reactor was cooled to <50 ° C. and vented to atmospheric pressure before removal. After hydrothermal crystallization, the pH of the resulting suspension was 12.0. The suspension was mixed with deionized water and filtered through a porcelain suction filter. The wet product was then heated in air to a temperature of 120 ° C. for 4 hours. The dried product was then further calcined at 600 ° C. for 5 hours in air so that the template was removed and the C content was less than 0.1% by weight.

  As can be observed in the SEM image of the crystalline form of FIG. 6, the as-synthesized snowball material (Example 2) will be identified by SEM analysis (secondary electron image) at a magnification of 5000 ×. And a characteristic secondary structure of a sphere having a diameter size of 1 to 2 μm. The individual crystals of the molecular sieve have a crystal size in the range of about 100-200 nm.

Example 3-Cu promotion An ion exchange reaction between the Na-type CHA of Example 2 and copper ions was performed by stirring the slurry at about 60 ° C for about 1 hour. The resulting mixture was then filtered to obtain a filter cake, which was washed in three portions with deionized water until the filtrate was clear and colorless, and the washed sample was dried.

The resulting CuCHA catalyst contained CuO in the range of about 1.5-4% by weight as measured by ICP analysis. A CuCHA slurry was prepared to 40% target solids. The slurry was crushed and a zirconium acetate binder (containing 30% ZrO ₂ ) dissolved in diluted acetic acid was added to the slurry with stirring.

Preparation Example 4 washcoat was then coated to washcoat loading of 2.1 g / in ³ A slurry of Example 3 on a substrate. The washcoat was dried in air at 130 ° C. for 5 minutes. After the final coating, the substrate was baked at 450 ° C. for 1 hour.

Example 5-Investigation of CuO loading The nitrogen oxide selective catalytic reduction (SCR) efficiency and selectivity of the fresh catalyst core was determined as NO 500 ppm, NH ₃ 500 ppm, O ₂ 10%, H ₂ O 5%, N ₂ residue. Minute feed gas mixture was measured by adding to a steady state reactor containing a 1 inch Dx3 inch L catalyst core. The reaction was carried out at a space velocity of 80,000 hr ⁻¹ across a temperature range of 150 ° C. to 460 ° C.

The sample was hydrothermally deteriorated at 750 ° C. for 5 hours in the presence of 10% H ₂ O and then nitrogen oxides in the same manner as outlined above for SCR evaluation of the fresh catalyst core. SCR efficiency and selectivity were measured.

FIG. 7 is a bar graph showing NO _x conversion rate (%) vs. CuO loading rate (mass%).

FIG. 8 is a bar graph showing N ₂ O production (ppm) versus CuO loading (mass%).

Nitrogen oxides selective catalytic reduction (SCR) efficiency and selectivity of Example 6-NO _x conversion fresh catalyst _{core, NO 500ppm, NH 3 500ppm,} O 2 10%, H 2 O 5%, N 2 residue Was added to a steady state reactor containing a 1 inch Dx3 inch L catalyst core. The reaction was carried out at a space velocity of 80,000 hr ⁻¹ across a temperature range of 150 ° C. to 460 ° C.

The sample was hydrothermally deteriorated at 750 ° C. for 5 hours in the presence of 10% H ₂ O and then nitrogen oxides in the same manner as outlined above for SCR evaluation of the fresh catalyst core. SCR efficiency and selectivity were measured.

FIG. 9 is a graph showing NO _x conversion (%) vs. temperature (° C.) for the catalyst of Example 1 (comparative) versus the catalyst of the invention of Example 3 (with CuO of 3.2%).

FIG. 10 is a graph showing NO _x production (ppm) vs. temperature (° C.) for the catalyst of Example 1 (comparative) versus the catalyst according to the invention of Example 3 (with 3.2% CuO).

FIG. 11 is a bar graph showing the NO _x conversion (%) at 20 ppm NH ₃ slip for the catalyst of Example 1 (comparative) versus the catalyst of the invention of Example 3 (with CuO of 3.2%). The catalyst of Example 3 shows significantly higher NO _x conversion (about 15% higher) at 20 ppm NH ₃ slip, which is an indicator of improved transient performance during engine test conditions.

As shown in FIGS. 9-11, the snowball configuration is a SCR catalyst material that has improved NO _x conversion efficiency and lower N ₂ O production relative to an SCR catalyst material that does not have a snowball configuration. Bring.

Molecular sieve with homomorphic replacement Example 7
Isomorphous substitution zeolite material (Na- [Ti] CHA), 0.03Al 2 O 3: SiO 2: 0.07TiO 2: 0.06Na 2 O: 0.08ATMAOH: 2.33H 2 O of gel compositions From 155 ° C. for 5 days by autoclave hydrothermal synthesis. The product was recovered by filtration and the template was removed by calcination at 600 ° C. for 5 hours. The final crystalline material had an X-ray powder diffraction pattern showing CHA phase> 90% and a silica / alumina ratio (SAR) of 25 by XRF.

Example 8
NH ₄ isomorphic substituted zeolite material (H- [Ti] CHA), obtained through twice _NH 4 _NO 3 in (2.4M) exchange with the material of Example 7 (Na- [Ti] CHA) - Prepared by firing [Ti] CHA at 500 ° C. (4 hours). The Ti level does not change through the NH ₄ NO ₃ exchange process (4.3% vs 4.5%).

Example 9-Comparison The zeolitic material H-CHA was prepared according to the process of Example 7 (H- [Ti] CHA), but no Ti was added to the synthesis gel.

Example 10
Copper-promoted isomorphous substituted zeolitic material (Cu2.72- [Ti] CHA) at 50 ° C. with the material of Example 8 (H- [Ti] CHA) and Cu (OAc) ₂ (0.06M) Which was prepared by ion exchange (2 hours) with a Cu content of 2.72% (ICP).

Example 11
Copper-promoted isomorphous substituted zeolitic material (Cu3.64- [Ti] CHA) at 50 ° C. with the material of Example 9 (H- [Ti] CHA) and Cu (OAc) ₂ (0.125 M) Prepared by ion exchange (2 hours) with a Cu content of 3.64% (ICP).

Example 12-Comparison A standard copper-promoted zeolitic material (Cu 2.75-CHA) was prepared according to the method provided in US Pat. No. 8,404,203 (B2), which is described in Example 9. It had a comparable Cu content (2.75%). This material is provided as a benchmark for benchmarking.

Example 13-Comparison A standard copper-promoted zeolitic material (Cu3.84-CHA) was prepared according to the method provided in US Pat. No. 8,404,203 (B2), which contained Cu comparable to Example 10. Had a rate (3.84%). This material is provided as a benchmark for benchmarking.

Example 14
Ti uptake at the tetrahedral position is evidenced by a skeletal stretch (Ti-O-Si) fingerprint with Ti at 940-980 cm- ¹ as shown in FIG.

Example 15
As shown in FIG. 13, in addition to fingerprint vibration from a skeletal stretch with Ti, an increase in skeletal acidity based on high valent skeleton Ti (IV) requires strong Lewis acidity for its formation This is proved by the increase in the strength of NO ⁺ .

Example 16
After exchanging Cu for the acid sites of the isomorphously substituted zeolitic material [Ti] CHA providing the compounds of Examples 10 and 11, there is no effect on the formation of NO ⁺ . As shown in FIG. 14, the material of Example 10 (Cu2.72- [Ti] CHA) has more NO ⁺ in equilibrium than the unmodified Comparative Example 12 (Cu2.75-CHA). Shows excellent ability to produce. Considering the highly reactive nature of NO ⁺ to nucleophiles, eg NH _3, the significant increase in reactivity observed at low temperatures (eg 200 ° C.) from Example 10 (Cu— [Ti] CHA) is , Based on improved production and retention of NO ⁺ on the catalyst.

Example 17
As can be observed in the SEM image of FIG. 15, as-synthesized [Ti] CHA (Example 8), as identified by SEM analysis (secondary electron image) at 5000 × magnification, It has a secondary structure characteristic of a sphere having a diameter size of 1 to 2 μm.

Example 18
The material of Example 10 (Cu— [Ti] CHA) was wash-coated on a flow-through ceramic substrate with a load of 2.1 g / in ³ . Typical SCR test conditions include simulated diesel exhaust (NO 500 ppm, NH ₃ 500 ppm, O ₂ 10%, H ₂ O 5% and N ₂ residue) and a temperature point of 200 ° C. to 600 ° C. included. The conversion of NO and NH ₃ at various temperatures is monitored by FTIR. When it is necessary to evaluate long-term hydrothermal durability, aging conditions are used in which H ₂ O is exposed to 10% at 750 ° C. for 5 hours.

  As shown in the SEM images of FIGS. 18A and 18B, as-synthesized Cu- [Ti] CHA is very porous when compared to a standard copper-promoted zeolitic material, Cu-CHA. A washcoat (FIG. 18B) results.

Example 19
The porosity and particle size of this material is presented in FIG. As shown in FIG. 19, when shown by Hg penetration measurement, the washcoat formed from Cu— [Ti] CHA (Example 10) is compared to unmodified Cu—CHA (Example 12), It has a porosity distribution towards larger pores.

  In addition to the increased porosity of the washcoat, as-synthesized Cu- [Ti] CHA results in a particle size that is significantly larger than the particle size of standard copper-promoted zeolitic material.

Example 20
The catalyst (Cu— [Ti] CHA) was wash coated on the flow-through ceramic substrate at a load of 2.1 g / in ³ . Typical SCR test conditions include simulated diesel exhaust (NO 500 ppm, NH ₃ 500 ppm, O ₂ 10%, H ₂ O 5% and N ₂ residue) and a temperature point of 200 ° C. to 600 ° C. included. The conversion of NO and NH ₃ at various temperatures is monitored by FTIR. When long-term hydrothermal durability needs to be evaluated, deterioration conditions are used in which H ₂ O is exposed to 10% at 750 ° C. for 5 hours.

As shown in FIG. 16, with the help of framework Ti (Example 10), the SCR performance at 200 ° C. is significant compared to a similar sample (Example 6) with equivalent Cu% and no Ti. It is observed that NO _x conversion efficiency at high temperature (600 ° C.) is not sacrificed at all.

Example 21
As shown in FIG. 17, as a result of the high Cu content after high temperature hydrothermal degradation (eg, SAR = 30, Cu%> 2.5%), CuO is formed, which actively consumes NH ₃ , Reduces SCR performance at the high temperature end. The presence of framework Ti (Example 11) helps to reduce NH ₃ consumption in the high temperature region due to samples with high Cu loading.

Example 22
An isomorphously substituted zeolitic material (Na- [Ti] AEI) is prepared in the same manner as the material of Example 7. The product is recovered by filtration and the template is removed by calcination at 600 ° C. for 5 hours.

Example 23
NH ₄ isomorphic substituted zeolite material (H- [Ti] AEI), obtained through twice _NH 4 NO ₃ exchange of the material (Na- [Ti] AEI) of Example 21 (2.4M) - Prepared by firing [Ti] AEI at 500 ° C. (4 hours).

Example 24
Copper promoted isomorphous substituted zeolitic material (Cu— [Ti] AEI) at 50 ° C. with the materials of Example 22 (H— [Ti] AEI) and Cu (OAc) ₂ (0.06 M). Prepare by ion exchange (2 hours).

Example 25
An isomorphously substituted zeolitic material (Na- [Ti] AFX) is prepared in the same manner as the material of Example 7. The product is recovered by filtration and the template is removed by calcination at 600 ° C. for 5 hours.

Example 26
NH ₄ isomorphic substituted zeolite material (H- [Ti] AFX), obtained through twice _NH 4 NO ₃ exchange of the material of Example 24 (Na- [Ti] AFX) (2.4M) - [Ti] Prepare by firing AFX at 500 ° C. (4 hours).

Example 27
Copper promoted isomorphous substituted zeolitic material (Cu— [Ti] AFX) at 50 ° C. with the material of Example 25 (H— [Ti] AFX) and Cu (OAc) ₂ (0.06 M). Prepare by ion exchange (2 hours).

Example 28
Isomorphous substitution zeolite material (Na- [Ti] CHA), 0.03Al 2 O 3: SiO 2: 0.07TiO 2: 0.06Na 2 O: 0.08ATMAOH: 2.33H 2 O of gel compositions From 155 ° C. for 5 days by autoclave hydrothermal synthesis. The product was collected by filtration and the template was removed by calcination at 600 ° C. for 5 hours. The final crystalline material had an X-ray powder diffraction pattern showing CHA phase> 90% and 25 SAR by XRF. Other SARs, such as 20, can also be obtained by appropriately adjusting the Si / Al ratio in the starting gel.

Example 29
Isomorphically substituted zeolitic material (H- [Ti] CHA) is obtained through two NH ₄ NO ₃ (2.4M) exchanges with the material of Example 27 (Na- [Ti] CHA) NH ₄ − Prepared by firing [Ti] CHA at 500 ° C. (4 hours). Ti level did not change throughout the NH ₄ NO ₃ exchange process (4.3% vs 4.5%).

Example 30
Zeolite material H-CHA was prepared according to the method of Examples 28 and 29, but no Ti was added to the initial synthetic sol gel for zeolite hydrothermal crystallization.

Example 31
Copper-promoted isomorphous substituted zeolitic material (Cu- [Ti] CHA (SAR20)) was exchanged with the materials of Example 29 (H- [Ti] CHA) and Cu (OAc) ₂ at 50 ° C. (2 hours). Changing the Cu concentration in the exchange process resulted in a series of copper zeolites: eg Cu 2.46- [Ti] CHA (Example 31a), Cu3.03- [Ti] CHA (Example 31b), Cu3.64- [Ti] CHA (Example 31c) and Cu3.78- [Ti] CHA (Example 31d) (numbers after Cu indicate Cu percentage).

Example 32
A standard copper-promoted zeolitic material (Cu 2.75-CHA) was prepared according to the method provided in US Pat. No. 8,404,203 (B2) and provided as a reference for benchmarking.

Example 33 - Comparative Fe-CHA: Synthesis of (Fe 2.5%), carried out in the same way as Cu-CHA (provided that with Fe _{(NO 3) 3} solution exchange), was selected as a comparative sample .

Example 34-Comparison Commercially available Fe-beta from BASF was selected as a comparative sample.

Example 35-Comparison A commercially available Fe-MFI (SCP-306) from Sued-Chemie was selected as a comparative sample.

Example 36
As shown in FIG. 20, in the presence of skeleton Ti, NH ₃ adsorbed in the high temperature zone not only increased from 15.2 to 19.1 cm ³ / g, but the desorption temperature was only 10 ° C. It is rising (eg from 470 ° C. to 480 ° C.), indicating that the Lewis acid sites other than acidic protons that function as NH ₃ storage components are stronger (Example 29 vs. Example 30).

Example 37
As shown in FIG. 21, after the Cu exchange, only the amount of NH ₃ stored in the intermediate temperature zone, for example, 250 ° C. to 400 ° C., was improved by the increase of the Cu percentage. The integrated values of the highest desorption peaks were Cu-CHA (Example 32), Cu2.46- [Ti] CHA (Example 31a), Cu3.03- [Ti] CHA (Example 31), Cu3.64- [ Ti] CHA (Example 31c) was 12.8, 23.8, 28.8 and 23.8 cm < ³ > / g, respectively. Ti-containing Cu- [Ti] CHA samples consistently exhibited double NH ₃ retention capacity above 400 ° C. (Example 32 vs. Example 31).

Example 38
As shown in FIG. 22, however, the presence of other lower valent transition metals such as Fe (III) did not have an effective promotion of NH ₃ storage above 400 ° C. The storage capacities of Fe-MFI, Fe-CHA, and Fe-beta at high temperatures (> 400 ° C.) are 13.6, 12.8, and 7.9 cm ³ / g, respectively, which are unmodified Cu-CHA and It was a similar level.

Example 39
Both Cu-CHA (Example 32) and Cu3.64- [Ti] CHA (Example 31c) were coated on the honeycomb with equal washcoat loading and temperature (200 ° C, 300 ° C, 400 ° C, The amount of NH ₃ stored in the presence of 5% H ₂ O was measured at 450 ° C. and 500 ° C.). As shown in FIG. 23, more chemisorbed NH ₃ was consistently seen on Cu— [Ti] CHA up to 400 ° C. than with unmodified Cu—CHA, assisted by framework Ti. It was issued.

Example 40
Commercial non-zeolite composites with TiO ₂ , Al ₂ O ₃ and SiO ₂ consisting of Ti, Si, Al-based oxides from the coprecipitation process also exhibited NH ₃ storage properties at high temperatures. As shown in FIG. 24, the storage capacity of the commercially available material was low compared to Cu—CHA (Example 32), but the desorption temperature further increased.

Example 41
An isomorphously substituted zeolitic material (Na- [Ti] AEI) is prepared in the same manner as the material of Example 27. The product is recovered by filtration and the template is removed by calcination at 600 ° C. for 5 hours.

Example 42
Isomorphously substituted zeolitic material (H- [Ti] AEI) is obtained through two NH ₄ NO ₃ (2.4M) exchanges with the material of Example 41 (Na- [Ti] AEI) NH ₄ − Prepared by firing [Ti] AEI at 500 ° C. (4 hours).

Example 43
Copper promoted isomorphous substituted zeolitic material (Cu— [Ti] AEI) at 50 ° C. with the materials of Example 42 (H— [Ti] AEI) and Cu (OAc) ₂ (0.06 M). Prepare by ion exchange (2 hours).

Example 44
An isomorphously substituted zeolitic material (Na- [Ti] AFX) is prepared in the same manner as the material of Example 27. The product is recovered by filtration and the template is removed by calcination at 600 ° C. for 5 hours.

Example 45
An isomorphously substituted zeolitic material (H- [Ti] AFX) is obtained through two NH ₄ NO ₃ (2.4M) exchanges with the material of Example 44 (Na- [Ti] AFX) NH ₄ − [Ti] Prepare by firing AFX at 500 ° C. (4 hours).

Example 46
Copper promoted isomorphous substituted zeolitic material (Cu— [Ti] AEX) at 50 ° C. with the materials of Example 45 (H— [Ti] AFX) and Cu (OAc) ₂ (0.06 M). Prepare by ion exchange (2 hours).

  The use of the terms “a” and “an” and “the” and similar referents in the context of describing the materials and methods described herein (especially in connection with the appended claims) Unless otherwise specified in the specification, or unless clearly contradicted by context, it should be construed to include both the singular and plural forms. The recitation of value ranges herein is merely intended to be used as a simple way to individually reference each individual value within the range, unless otherwise indicated herein. Thus, each individual value is individually incorporated herein as listed herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any of the examples or exemplary terms provided herein (eg, “to, etc.”) is intended merely to provide a clear explanation of materials and methods, particularly patents. It is not intended to limit the scope unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosed materials and methods.

  Throughout this specification, reference to “one embodiment”, “a particular embodiment”, “one or more embodiments” or “an embodiment” refers to a particular feature, structure, or structure described in connection with the embodiment. Means that a material or property is included in at least one embodiment of the invention. Accordingly, phrases such as “in one or more embodiments”, “in a particular embodiment”, “in one embodiment”, or “in an embodiment” appear in various places throughout this specification. It does not necessarily refer to the same embodiment of the present invention. Furthermore, individual features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments.

  Although the invention has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the method and apparatus of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention include modifications and variations that are within the scope of the appended claims and their equivalents.

  10 spherical particles, 20 molecular sieve crystals, 30 microaggregates, 200 SCR catalyst composite, 210 ammonia storage material, 220 SCR catalyst material, 230 substrate, 240 inlet end, 250 outlet end, 260 channel, 210a first zone , 220a second zone, 110 SCR catalyst composite, 112 substrate, 113 substrate, 118 ammonia storage material, 120 SCR catalyst material, 122a inlet end, 124a outlet end, 122b inlet end, 124b outlet end, 118a first Zone, 120a second zone, 35 wall flow filter substrate, 52 passage, 53 inner wall, 54 inlet, 56 outlet, 58 inlet plug, 60 outlet plug, 62 gas flow, 64 unblocked inlet, 6 outlet side

Claims (40)

  An SCR catalyst comprising a zeolite framework material of silicon atoms and aluminum atoms, wherein a part of the silicon atoms are isomorphously substituted with a tetravalent metal, and the catalyst comprises Cu, Fe, Co, Ni, The SCR catalyst promoted with a metal selected from La, Ce, Mn, V, Ag and combinations thereof.   The catalyst of claim 1, wherein the tetravalent metal comprises a tetravalent transition metal.   The catalyst according to claim 2, wherein the tetravalent transition metal is selected from the group consisting of Ti, Zr, Hf, Ge, and combinations thereof.   The catalyst according to claim 3, wherein the tetravalent transition metal contains Ti.   The catalyst of claim 1 having a silica / alumina ratio in the range of 1 to 300.   The catalyst according to claim 5, wherein the silica / alumina ratio is in the range of 1-50.   The catalyst of claim 1 having a tetravalent metal / alumina ratio in the range of 0.0001 to 1000.   The catalyst according to claim 7, wherein the tetravalent metal / alumina ratio is in the range of 0.01-10.   The catalyst according to claim 8, wherein the tetravalent metal / alumina ratio is in the range of 0.01-2.   The catalyst of claim 1 having a silica / 4 valent metal ratio in the range of 1-100.   The catalyst according to claim 10, wherein the silica / 4 valent metal ratio is in the range of 5-20.   The catalyst according to claim 1, wherein the zeolite framework material has a ring size of 12 or less.   The catalyst according to claim 12, wherein the zeolite framework material comprises d6r units.   The zeolite framework material is AEI, AFT, AFX, CHA, EAB, EMT, ERI, FAU, GME, JSR, KFI, LEV, LTL, LTN, MOZ, MSO, MWW, OFF, SAS, SAT, SAV, SBS, 14. A catalyst according to claim 13 selected from SBT, SFW, SSF, SZR, TSC, WEN and combinations thereof.   15. A catalyst according to claim 14 wherein the zeolite framework material is selected from AEI, CHA, AFX, ERI, KFI, LEV and combinations thereof.   The catalyst according to claim 1, wherein the zeolite framework material is selected from CHA.   The catalyst of claim 1, wherein the catalyst is promoted with Cu, Fe, and combinations thereof. The catalyst of claim 1, wherein the catalyst is effective to promote the formation of NO ⁺ . A method of selectively reducing nitrogen oxides (NO _x ), comprising contacting an exhaust gas stream containing NO _x with a catalyst comprising a zeolite framework material of silicon atoms and aluminum atoms, wherein The method, wherein a portion of the silicon atoms are isomorphously substituted with a tetravalent metal.   An exhaust gas treatment system comprising an exhaust gas stream containing ammonia and the catalyst of claim 1 effective to decompose at least a portion of the ammonia in the exhaust gas stream. An SCR catalyst complex,
An SCR catalyst material that promotes the reaction between ammonia and nitrogen oxides to selectively form nitrogen and H ₂ O over a temperature range of 150 ° C. to 600 ° C .;
An ammonia storage material comprising a transition metal having an oxidation number IV, the SCR catalyst material being effective for storing ammonia at 400 ° C. or higher, and a minimum NH ₃ storage amount at 400 ° C. of 0.1 g / The SCR catalyst composite which is L.   The SCR catalyst composite of claim 21, wherein the transition metal is selected from the group consisting of Ti, Ce, Zr, Hf, Ge, and combinations thereof.   The SCR catalyst composite of claim 21, wherein the SCR catalyst material is isomorphously substituted with the ammonia storage material.   The SCR catalyst composite according to claim 21, wherein the ammonia storage material is dispersed in the SCR catalyst material.   The SCR catalyst composite according to claim 21, wherein the ammonia storage material is dispersed as a layer on the SCR catalyst material.   The SCR catalyst composite according to claim 21, wherein the ammonia storage material and the SCR catalyst material are arranged in a zone.   27. The SCR catalyst complex of claim 26, wherein the ammonia storage material is upstream of the SCR catalyst material.   The catalyst composite according to claim 21, wherein the SCR catalyst material is ion exchanged with the ammonia storage material.   The SCR catalyst composite of claim 21, wherein the SCR catalyst material is deposited on a substrate.   30. The SCR catalyst composite according to claim 29, wherein the substrate is selected from a wall flow type filter and a flow through type substrate.   24. The SCR catalyst composite of claim 21, wherein the SCR catalyst material comprises one or more of molecular sieves, mixed oxides, and activated refractory metal oxide supports.   The mixed oxide is Fe / titania, Fe / alumina, Mg / titania, Mg / alumina, Mn / alumina, Mn / titania, Cu / titania, Ce / Zr, Ti / Zr, vanadia / titania and mixtures thereof. Selected and activated refractory metal oxide support is alumina, ceria, zirconia, silica, titania, silica-alumina, zirconia-alumina, titania-alumina, lantana-alumina, lantana-zirconia-alumina, barrier 32. selected from alumina, barrier-lanthana-alumina, barrier-lanthana-neodymia-alumina, alumina-chromia, alumina-ceria, zirconia-silica, titania-silica, or zirconia-titania, and combinations thereof The SCR catalyst complex described in 1.   The SCR catalyst composite according to claim 32, wherein the silica / alumina ratio is in the range of 1 to 300.   The SCR catalyst material comprises a molecular sieve having a skeleton of silicon atoms, phosphorus atoms and aluminum atoms, and the ratio of alumina to transition metal is in the range of 1:10 to 10: 1. SCR catalyst complex.   The SCR catalyst according to claim 32, wherein the SCR catalyst material comprises a molecular sieve having a skeleton of silicon atoms, phosphorus atoms and aluminum atoms, and a part of the silicon atoms is isomorphously substituted with a metal of the ammonia storage material. Catalyst complex.   32. The SCR catalyst composite of claim 31, wherein the molecular sieve has a ring size of 12 or less.   The molecular sieve is MFI, BEA, AEI, AFT, AFX, CHA, EAB, EMT, ERI, FAU, GME, JSR, KFI, LEV, LTL, LTN, MOZ, MSO, MWW, OFF, SAS, SAT, SAV 37. The SCR catalyst complex of claim 36, having a structural type selected from the group consisting of: SBS, SBT, SFW, SSF, SZR, TSC, WEN and combinations thereof.   23. The SCR catalyst composite of claim 21, wherein the SCR catalyst material is promoted with a metal selected from Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag, and combinations thereof. A method of simultaneously performing selective reduction of nitrogen oxides (NO _x ) and storage of ammonia, wherein an exhaust gas stream containing NO _x is promoted to promote the reaction between ammonia and nitrogen oxides at 150 ° C. to Contacting the SCR catalyst composite comprising an SCR catalyst material that selectively forms nitrogen and H ₂ O over a temperature range of 600 ° C., and an ammonia storage material comprising a transition metal having an oxidation number IV, The method, wherein the catalyst material is effective to store ammonia at 400 ° C. or higher, and the minimum NH ₃ storage at 400 ° C. is 0.1 g / L. An SCR catalyst complex,
An SCR catalyst material that efficiently promotes the reaction between ammonia and nitrogen oxides to selectively form nitrogen and H ₂ O over a temperature range of 200 ° C. to 600 ° C .;
The SCR catalyst composite, wherein the SCR catalyst material comprises SSZ-13, and the ammonia storage material is effective to store ammonia at 400 ° C. or higher. body.

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