CN106660021B

CN106660021B - Molecular sieve catalyst compositions, catalytic composites, systems, and methods

Info

Publication number: CN106660021B
Application number: CN201580043934.6A
Authority: CN
Inventors: 杨晓帆; J·K·霍克默思; W-M·薛; X·王; M·T·考德; A·莫伊尼; D·O·贺罗巴夫; Q·傅; M·布林
Original assignee: BASF Corp
Current assignee: BASF Corp
Priority date: 2014-06-18
Filing date: 2015-06-17
Publication date: 2020-09-11
Anticipated expiration: 2035-06-17
Also published as: KR20170021835A; EP3157672A4; JP2017521241A; RU2017101429A; EP3157671A1; CN106660022B; EP3157671A4; BR112016029733A2; BR112016029733A8; BR112016029733B8; CA2952437A1; JP6882427B2; RU2727801C2; JP6615794B2; MX2023001935A; CN106660021A; RU2017101429A3; BR112016029733B1; MX2016016920A; WO2015195819A1

Abstract

A selective catalytic reduction catalyst comprising a zeolitic framework material of silicon and aluminum atoms wherein a portion of the silicon atoms are isomorphously substituted with a tetravalent metal is described. The catalyst may include a promoter metal effective to selectively promote the reaction of ammonia and nitrogen oxides to form nitrogen and H over a temperature range of 150 to 650 DEG C₂And O. In another aspect, a selective catalytic reduction composite is described that includes an SCR catalyst material and an ammonia storage material that includes a transition metal having an oxidation state IV. The SCR catalyst material selectively promotes the reaction of ammonia and nitrogen oxides to form nitrogen and H within a temperature range of 150 ℃ to 600 ℃₂O, and the ammonia storage material effectively stores ammonia at 400 ℃ and higher. A method of selectively reducing nitrogen oxides, and a method of simultaneously selectively reducing nitrogen oxides and storing ammonia are also described. Additionally, an exhaust treatment system is also described.

Description

Molecular sieve catalyst compositions, catalytic composites, systems, and methods

Technical Field

The present invention relates generally to the field of selective catalytic reduction materials, selective catalytic reduction composites, and methods of selectively reducing nitrogen oxides. More particularly, embodiments of the present invention relate to SCR catalyst materials comprising spherical particles including agglomerates of molecular sieve crystals.

Background

Nitrogen Oxides (NO) for a long time_x) The harmful components have caused atmospheric pollution. Containing NO in exhaust gases, e.g. from internal combustion engines (e.g. cars and trucks), from combustion plants (e.g. natural gas, oil or coal-heated power stations) and from nitric acid production plants_x。

The treatment of NO-containing materials has been carried out using various methods_xThe gas mixture of (1). One type of treatment involves the catalytic reduction of nitrogen oxides. There are two methods: (1) a non-selective reduction process in which carbon monoxide, hydrogen or a lower hydrocarbon is used as a reducing agent, and (2) a selective reduction process in which ammonia or an ammonia precursor is used as a reducing agent. In the selective reduction method, a high degree of removal of nitrogen oxides can be obtained with a small amount of reducing agent.

The selective reduction process is called SCR process (selective catalytic reduction). The SCR process catalytically reduces nitrogen oxides with ammonia in the presence of atmospheric oxygen to form primarily nitrogen and water vapor:

4NO+4NH₃+O₂→4N₂+6H₂o (Standard SCR reaction)

2NO₂+4NH₃→3N₂+6H₂O (slow SCR reaction)

NO+NO₂+NH₃→2N₂+3H₂O (Rapid SCR reaction)

The catalyst used in the SCR process should ideally be able to maintain good catalytic activity under hydrothermal conditions over a wide range of application temperature conditions, for example from 200 ℃ to 600 ℃ or higher. Hydrothermal conditions are often encountered in practice, such as during regeneration of a soot filter (a component of an exhaust gas treatment system for particulate removal).

Molecular sieves, such as zeolites, have been used for Selective Catalytic Reduction (SCR) of nitrogen oxides with a reducing agent, such as ammonia, urea, or a hydrocarbon, in the presence of oxygen. Zeolites are crystalline materials having fairly uniform pore sizes, which are about 3 to 10 angstroms in diameter, depending on the type of zeolite and the type and amount of cations contained in the zeolite lattice. Zeolites having 8-ring pore openings and double-six-ring (double-sixring) secondary building blocks, particularly those having a cage structure, have recently been found to be useful as SCR catalysts. One particular type of zeolite with these properties is Chabazite (CHA), which is a small pore zeolite with 8-membered ring pore openings (3.8 angstroms) accessible through its three-dimensional pores. The cage structure comes from connecting double six-ring structural units by 4 rings.

Metal-promoted zeolite catalysts for the selective catalytic reduction of nitrogen oxides with ammonia are known, including, inter alia, iron-promoted and copper-promoted zeolite catalysts. Iron-promoted zeolite beta has been an effective commercial catalyst for the selective reduction of nitrogen oxides with ammonia. Unfortunately, it has been found that under severe hydrothermal conditions, such as those present during regeneration of soot filters having temperatures locally exceeding 700 ℃, the activity of many metal-promoted zeolites begins to decline. This reduction is generally attributed to dealumination of the zeolite and the consequent loss of metal-containing active sites within the zeolite.

Metal-promoted, particularly copper-promoted aluminosilicate zeolites having the CHA structure type have recently attracted considerable interest as catalysts for SCR of nitrogen oxides in lean burn engines using nitrogenous reductants. This is because these materials, as described in U.S. Pat. No.7,601,662, combine a wide temperature window with excellent hydrothermal durability. Prior to the discovery of the metal-promoted zeolites described in U.S. patent No.7,601,662, while the literature has shown that a number of metal-promoted zeolites have been proposed in the patent and scientific literature for use as SCR catalysts, the proposed materials suffer from one or all of the following disadvantages: (1) poor conversion of nitrogen oxides at low temperatures, e.g., 350 ℃ and lower; and (2) poor hydrothermal stability, which manifests as a significant decrease in catalytic activity in the conversion of nitrogen oxides by SCR. Accordingly, the invention described in U.S. Pat. No.7,601,662 addresses an urgent and unresolved need to provide materials that achieve conversion of nitrogen oxides at low temperatures and retention of SCR catalytic activity after hydrothermal aging at temperatures in excess of 650 ℃.

Although existing catalysts exhibit excellent properties, there is still a need to reduce N during SCR reactions₂And (4) O yield. Accordingly, there is a need for improved NO compared to the prior art_xConversion efficiency and lower N₂O-production SCR catalyst.

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 agglomerates of molecular sieve crystals, wherein the spherical particles have a median particle size in a range of from about 0.5 to about 5 microns.

In a second embodiment, the SCR catalyst material of the first embodiment is modified, wherein the molecular sieve comprises d6r units.

In a third embodiment, the SCR catalyst material of the first and second embodiments is modified, wherein the molecular sieve has a structure type selected from the group consisting of 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.

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

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

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

In a seventh embodiment, the SCR catalyst material of the first through sixth embodiments is modified, wherein the molecular sieve having the CHA structure type is selected from the group consisting of aluminosilicate zeolites, borosilicates, gallosilicates (gallosilicates), SAPOs, alpos, meapsos, and MeAPO.

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

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

In a tenth embodiment, the SCR catalyst material of the first through ninth embodiments is modified, wherein the molecular sieve is promoted with a metal selected from Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag, and combinations thereof.

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

In a twelfth embodiment, the SCR catalyst material of the first through eleventh embodiments is modified, wherein the SCR catalyst material is effective to catalyze the selective catalytic reduction of nitrogen oxides in the presence of a reductant at a temperature of 200 ℃ to 600 ℃.

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

In a fourteenth embodiment, the SCR catalyst material of the tenth through eleventh embodiments is modified, wherein the metal is present in an amount of about 0.1 to about 10 wt.% on an oxide basis.

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

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

In an eighteenth embodiment, the SCR catalyst material of the first through seventeenth embodiments is modified, wherein the SCR catalyst material is in the form of a washcoat (washcoat).

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

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

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

In a 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 through twenty-second embodiments is modified, wherein at least 80% of the spherical particles have a median particle size in the range of from 0.5 to 2.5 microns.

In a twenty-fourth embodiment, the SCR catalyst material of the first through twenty-third embodiments is modified, wherein the molecular sieve comprises a zeolitic framework material of silicon and aluminum atoms, wherein a portion of the silicon atoms are isomorphously substituted with a tetravalent metal.

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

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

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

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

A second aspect of the invention relates to the selective reduction of Nitrogen Oxides (NO)_x) The method of (1). In a twenty-ninth embodiment, selective reduction of Nitrogen Oxides (NO)_x) The method comprises allowing NO to be contained_xIs contacted with an SCR catalyst material comprising spherical particles comprising agglomerates of molecular sieve crystals, wherein the spherical particles have a median particle size in a range of from about 0.5 to about 5 microns. In other embodiments, the Nitrogen Oxides (NO) are selectively reduced_x) The method comprises allowing NO to be contained_xIs contacted with the SCR catalyst material of the first through twenty-eighth embodiments.

A third aspect of the invention relates to a method for treating NO-containing gas from a lean burn engine_xThe system for exhausting gas of (1). In a thirtieth embodiment, for treating NO-containing gas from lean-burn engines_xThe system for exhaust gas of (a) comprises the SCR catalyst material of the first to twenty-eighth embodiments and at least one other exhaust gas treatment component.

A thirty-first embodiment is directed to an SCR catalyst comprising a zeolitic framework material of silicon and aluminum atoms, wherein a portion of the silicon atoms are isomorphously substituted with a tetravalent metal and the catalyst is promoted with a metal selected from the group consisting of Cu, Fe, Co, Ni, La, 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 comprises 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 Ti, Zr, Hf, Ge and combinations thereof.

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

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

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

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

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

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

In a fortieth embodiment, the SCR catalyst of the thirty-first through thirty-ninth embodiments is modified, wherein the ratio of silica to tetravalent metal is in the range of 1 to 100.

In a forty-first embodiment, the SCR catalyst of the thirty-first through fortieth embodiments is modified, wherein the ratio of silica to tetravalent metal is in the range of 5 to 20.

In a forty-second embodiment, the SCR catalyst of the thirty-first through forty-first embodiments is modified, wherein the zeolitic framework material comprises a ring size of no greater than 12.

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

In a forty-fourth embodiment, the SCR catalyst of the thirty-first through forty-third embodiments is modified, wherein the zeolitic framework material is selected from the group consisting of 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.

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

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

In a forty-seventh embodiment, the SCR catalyst of the thirty-first through forty-sixth embodiments is modified, wherein the zeolitic framework material is CHA.

In a forty-eighth embodiment, the SCR catalyst of the thirty-first through 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 through forty-eighth embodiments is modified, wherein the catalyst is effective to promote NO⁺Is performed.

In a fifty-first embodiment, the SCR catalyst of the thirty-first through forty-ninth embodiments is modified, with the proviso that the zeolite framework does not include phosphorus atoms.

Embodiments of another aspect of the invention relate to the selective reduction of Nitrogen Oxides (NO)_x) The method of (1). In a fifty-first embodiment, Nitrogen Oxides (NO) are selectively reduced_x) The method comprises allowing NO to be contained_xIs contacted with the catalyst of the thirty-first through fifty-fifth embodiments.

Embodiments of another aspect of the invention relate to an exhaust gas treatment system. In a fifty-second embodiment, an exhaust gas treatment system includes an exhaust gas stream comprising ammonia and a catalyst according to the thirty-first through fifty-second embodiments.

In another aspect, a fifty-third embodiment is provided that relates to the catalyst of any one of the first to fifteenth embodiments as being for selective catalytic reduction of NO in the presence of ammonia_xThe use of the catalyst of (1).

A fifty-fourth embodiment is directed to an SCR catalyst composite comprising selectively promoting a reaction of ammonia and nitrogen oxides to form nitrogen and H within a temperature range of 150 ℃ to 600 ℃₂SCR catalyst material of O; and an ammonia storage material comprising a transition metal having an oxidation state IV, the ammonia storage material being effective to store ammonia at 400 ℃ and above, with a minimum NH of 0.1g/L at 400 ℃₃And (4) storing quantity.

In a fifty-fifth embodiment, the SCR catalyst composite of the fifty-fourth embodiment is modified, wherein the transition metal is selected from the group consisting of Ti, Ce, Zr, Hf, Ge, and combinations thereof.

In a fifty-sixth embodiment, the SCR catalyst composite of the fifty-fourth and fifty-fifth embodiments is modified, wherein the SCR catalyst material is isomorphously substituted with an ammonia storage material.

In a fifty-seventh embodiment, the SCR catalyst composite of the fifty-fourth and fifty-fifth embodiments is modified, wherein the ammonia storage material is dispersed in the SCR catalyst material.

In a fifty-eighth embodiment, the SCR catalyst composite of the fifty-fourth and fifty-fifth embodiments is modified, wherein the ammonia storage material is dispersed as a layer on the SCR catalyst material.

In a fifty-ninth embodiment, the SCR catalyst composite of the fifty-fourth and fifty-fifth embodiments is modified, wherein the ammonia storage material and the SCR catalyst material are arranged in a zoned configuration.

In a sixteenth embodiment, the SCR catalyst composite of the fifty-ninth embodiment is modified, wherein the ammonia storage material is upstream of the SCR catalyst material.

In a sixteenth embodiment, the SCR catalyst composite of the fifty-fourth and fifty-fifth embodiments is modified, wherein the SCR catalyst material is ion exchanged with the ammonia storage material.

In a sixty-second embodiment, the SCR catalyst composite of the fifty-fourth to sixty-first embodiments is modified, wherein the SCR catalyst material is disposed on a filter.

In a sixty-third embodiment, the SCR catalyst composite of the sixty-second embodiment is modified, wherein the filter is a wall-flow filter.

In a sixty-fourth embodiment, the SCR catalyst composite of the sixty-second embodiment is modified, wherein the filter is a flow-through filter.

In a sixty-fifth embodiment, the SCR catalyst composite of the fifty-fourth to sixty-fourth embodiments is modified, wherein the SCR catalyst material comprises one or more of a molecular sieve, a mixed oxide, and an activated refractory metal oxide support.

In a sixty-sixth embodiment, the SCR catalyst composite of the sixty-fifth embodiment is modified, wherein the mixed oxide is selected from the group consisting of Fe/titania, Fe/alumina, Mg/titania, Mg/alumina, Mn/titania, Cu/titania, Ce/Zr, Ti/Zr, vanadia/titania, and mixtures thereof.

In a sixty-seventh embodiment, the SCR catalyst composite of the sixty-fifth and sixty-sixth embodiments is modified, wherein the mixed oxide comprises vanadium oxide/titanium dioxide and is stabilized with tungsten.

In a sixty-eighth embodiment, the SCR catalyst composite of the sixty-fifth embodiment is modified, wherein the molecular sieve has a framework of silicon, phosphorus, and aluminum atoms.

In a sixty-ninth embodiment, the SCR catalyst composite of the sixty-eighth embodiment is modified wherein the silica to alumina ratio is in the range of 1 to 300.

In a seventeenth embodiment, the SCR catalyst composite of the sixty-eighth and sixty-ninth embodiments is modified, wherein the ratio of silica to alumina is in the range of 1 to 50.

In a seventy-first embodiment, the SCR catalyst composite of the sixty-eight to seventy-fourth embodiments is modified, wherein the ratio of alumina to tetravalent metal is in the range of 1:10 to 10: 1.

In a seventy-second embodiment, the SCR catalyst composite of the sixty-eighteenth to seventy-first embodiments is modified, wherein a portion of the silicon ions are isomorphously substituted with the metal of the ammonia storage material.

In a seventy-third embodiment, the SCR catalyst composite of the sixty-eighth embodiment is modified, wherein the molecular sieve comprises a ring size of no greater than 12.

In a seventy-second embodiment, the SCR catalyst composite of the sixty-eighth to seventy-third embodiments is modified, wherein the molecular sieve has a structure type selected from the group consisting of 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.

In a seventy-third embodiment, the SCR catalyst composite of the seventy-second embodiment is modified, wherein the molecular sieve has a structure type selected from the group consisting of MFI, BEA, CHA, AEI, AFX, ERI, KFI, LEV, and combinations thereof.

In a seventy-fourth embodiment, the SCR catalyst composite of the seventy-third embodiment is modified, wherein the molecular sieve has a structure type selected from the group consisting of AEI, CHA, AFX, and combinations thereof.

In a seventy-fifth embodiment, the SCR catalyst composite of the fifty-fourth through seventy-fourth embodiments is modified, wherein the SCR catalyst material is promoted with a metal selected from Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag, and combinations thereof.

In a seventy-sixth embodiment, the SCR catalyst composite of the fifty-fourth through seventy-fourth embodiments is modified, wherein the SCR catalyst material is promoted with Cu, Fe, and combinations thereof.

In a seventy-seventh embodiment, the SCR catalyst composite of the sixty-fifth embodiment is modified, wherein the molecular sieve comprises SSZ-13, SSZ-39, or SAPO-34.

In a seventy-eighth embodiment, the SCR catalyst composite of the sixty-fifth embodiment is modified, wherein the activated refractory metal oxide support is selected from the group consisting of alumina, ceria, zirconia, silica, titania, silica-alumina, zirconia-alumina, titania-alumina, lanthana-zirconia-alumina, baria-lanthana-neodymia-alumina, alumina-chromia, alumina-ceria, zirconia-silica, titania-silica, or zirconia-titania, and combinations thereof.

In a seventy-ninth embodiment, the SCR catalyst composite of the seventy-eighth embodiment is modified, wherein the activated refractory metal oxide support is exchanged with a metal selected from Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag, and combinations thereof.

In an eighty embodiment, the SCR catalyst composite of the sixty-fifth embodiment is modified, wherein the transition metal comprises Ti.

In an eighty-first embodiment, the SCR catalyst composite of the eighty-first embodiment is modified, wherein the ratio of alumina to titanium is in the range of 1:10 to 10: 1.

Another aspect of the invention relates to a method. In an eighty-second embodiment, the selective reduction of Nitrogen Oxides (NO) is performed simultaneously_x) And the method for storing ammonia comprises allowing NO to be contained_xIs contacted with the SCR catalyst composite of the fifty-fourth to eighty-first embodiments.

In an eighty-third embodiment, the method of the eighty-second embodiment is modified, wherein the oxygen content of the exhaust stream is from 1 to 30% and the water content of the exhaust stream is from 1 to 20%.

Another aspect of the invention relates to an SCR catalyst composite. In an eighty-fourth embodiment, an SCR catalyst composite comprises: effective to selectively promote the reaction of ammonia and nitrogen oxides to form nitrogen and H in the temperature range of 200 ℃ to 600 ℃₂O, wherein the SCR catalyst material comprises SSZ-13; and an ammonia storage material containing Ti, the ammonia storage material being effective to store ammonia at a temperature of 400 ℃ and higher.

Brief Description of Drawings

FIG. 1 is a schematic illustration of a cross-section of an SCR catalyst material according to one or more embodiments;

FIG. 2 shows a partial cross-sectional view of an SCR catalyst composite according to one or more embodiments;

FIG. 3 shows a partial cross-sectional view of an SCR catalyst composite according to one or more embodiments;

FIG. 4A shows a perspective view of a wall-flow filter substrate;

FIG. 4B shows a cross-sectional view of a section of a wall-flow filter substrate;

fig. 5 is an SEM image showing a crystal morphology of the catalyst material according to the example;

fig. 6 is an SEM image showing a crystal morphology of a catalyst material according to a comparative example;

FIG. 7 is a diagram comparing NO of catalysts according to examples_xHistogram of conversion;

FIG. 8 is a graph comparing N of catalysts according to examples₂Histogram of O yield;

FIG. 9 is a diagram comparing NO of catalysts according to examples_xA plot of conversion;

FIG. 10 is a graph comparing N of catalysts according to examples₂A plot of O production;

FIG. 11 is a graph comparing catalysts according to examples at 20ppm NH₃Slip (NH)₃slip) of NO_xHistogram of conversion;

FIG. 12 is an ATR analysis of a catalyst according to an embodiment;

FIG. 13 is an FTIR analysis of a catalyst according to an embodiment;

FIG. 14 is an FTIR analysis of a catalyst according to an embodiment;

FIG. 15 is a scanning electron microscope image of a material according to an embodiment;

FIG. 16 compares NO of catalysts according to examples_xConversion rate;

FIG. 17 compares NO of catalysts according to examples_xConversion rate;

18A and 18B are scanning electron microscope images of materials according to embodiments;

FIG. 19 is washcoat porosity measurement of a catalyst according to an example;

FIG. 20 compares NH of catalysts according to examples₃Absorption;

FIG. 21 compares NH of catalysts according to examples₃Absorption;

FIG. 22 compares NH of catalysts according to embodiments₃Absorption;

FIG. 23 compares NH of catalysts according to examples₃Absorption; and is

FIG. 24 compares NH of catalysts according to examples₃And (4) absorbing.

Detailed description of the invention

Before describing several exemplary embodiments of the invention, it is to be understood that the 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 of being carried out in various ways.

Government regulations require the use of NO for light and heavy vehicles_xAnd (3) emission reduction technology. NO Using Urea_xSelective Catalytic Reduction (SCR) for NO control_xEfficient and mainstream emission control techniques. In order to comply with government regulations, there is a need for SCR catalysts with improved performance compared to the existing Cu-SSZ-13 based baseline technology. Provides improved NO over existing Cu-SSZ-13 based baseline technology_xConversion efficiency and lower N₂O-yield SCR catalyst material. The SCR catalyst material is inEffective to selectively promote the reaction of ammonia and nitrogen oxides to form nitrogen and H in a temperature range of 200 ℃ to 600 ℃₂O。

Embodiments of the present invention relate to selective catalytic reduction materials comprising spherical particles comprising agglomerates of molecular sieve crystals. It has surprisingly been found that spherical particles having an agglomeration of molecular sieve crystals are particularly suitable for use in exhaust gas purification catalyst components, in particular as SCR catalyst materials.

With respect to the terms used in this disclosure, the following definitions are provided.

The term "catalyst" or "catalyst composition" or "catalyst material" as used herein refers to a material that promotes a reaction.

The term "catalytic article" or "catalyst composite" as used herein refers to an element used to promote a desired reaction. For example, the catalytic article or catalyst composite may comprise a washcoat containing catalytic species, such as a catalyst composition, on a substrate.

As used herein, the term "selective catalytic reduction" (SCR) refers to the reduction of nitrogen oxides to dinitrogen (N) using a nitrogenous reductant₂) The catalytic process of (1).

The term "FTIR" as used herein refers to fourier transform infrared spectroscopy, which is a technique used to obtain infrared spectra of absorption, emission, photoconductivity, or raman scattering of solids, liquids, or gases.

The term "ATR" as used herein refers to attenuated total reflection, which is a sampling technique used in conjunction with infrared spectroscopy, in particular FTIR, that enables direct inspection of samples in solid or liquid state without further preparation.

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

The term "molecular sieve" as used herein refers to framework materials, such as zeolites and other framework materials (e.g., isomorphously substituted materials), which can be used as catalysts in particulate form in combination with one or more promoter metals. Is divided intoThe sub-sieve is based on a material containing a large three-dimensional network of oxygen ions having sites of generally tetrahedral type and having a substantially uniform pore distribution, the average pore diameter being no greater than

The aperture is defined by the ring size. The term "zeolite" as used herein refers to a specific example of a molecular sieve comprising silicon and aluminum atoms. In accordance with one or more embodiments, it is to be understood that by defining a molecular sieve by a molecular sieve structure type, it is intended to include that structure type and any and all isomorphic framework materials having the same structure type as zeolitic materials, such as SAPO, ALPO, and MeAPO materials.

In a more specific embodiment, reference to an aluminosilicate zeolite structure type limits the material to molecular sieves that do not include phosphorus or other metals substituted in the framework. However, for clarity, as used herein, "aluminosilicate zeolite" excludes aluminophosphate materials, such as SAPO, ALPO, and MeAPO materials, and the broader term "zeolite" is intended to include aluminosilicates and aluminophosphates. Zeolites are crystalline materials having fairly uniform pore sizes, which are about 3 to 10 angstroms in diameter, depending on the type of zeolite and the type and amount of cations contained in the zeolite lattice. Zeolites typically comprise a silica/alumina (SAR) molar ratio of 2 or greater.

The term "aluminophosphate" refers to another specific example of a molecular sieve comprising aluminum and phosphate (phosphate) atoms. Aluminophosphates are crystalline materials with fairly uniform pore sizes.

Generally, molecular sieves, such as zeolites, are defined as having a common angle TO₄An aluminosilicate of an open three-dimensional framework structure of tetrahedral constitution, wherein T is Al or Si, or optionally P. The cations that balance the charge of the anionic backbone are loosely associated with the backbone oxygen, and the remaining pore volume is filled with water molecules. The non-framework cations are typically exchangeable, and water molecules are removable.

In an exemplary embodiment, the molecular sieve may be isomorphously substituted. The terms "zeolitic framework" and "zeolitic framework material" as used herein refer to a specific example of a molecular sieve further comprising silicon and aluminum atoms. According to an embodiment of the present invention, a molecular sieve comprises a silicon (Si) and aluminum (Al) ion zeolitic framework material, wherein a portion of the silicon atoms are isomorphously substituted with a tetravalent metal. In particular embodiments, the backbone does not include a phosphorus (P) atom.

The terms "isomorphously substituted" and "isomorphous substitution" as used herein refer to the substitution of one element for another element in a mineral without significantly altering the crystal structure. The elements that may be substituted for each other generally 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 portion of the silicon atoms in the zeolitic framework material are replaced by tetravalent metal. Such isomorphous substitution does not significantly alter the crystal structure of the zeolitic framework material.

The term "tetravalent metal" as used herein refers to a metal having a state in its valence (outermost electron shell) that can provide four electrons for covalent chemical bonding. Tetravalent metals include germanium (Ge) and those transition metals 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 a particular embodiment, the tetravalent metal comprises Ti.

In other embodiments, a portion of the silicon atoms are isomorphously substituted with a transition metal having an oxidation state of IV. Without wishing to be bound by theory, it is believed that the presence of elements having the oxidation state of form IV helps to improve ammonia storage at high temperatures. In one or more embodiments, the transition metal having an oxidation state of IV can be in the form of an oxide or inherently embedded in the SCR catalyst material. The term "transition metal having an oxidation state of IV" as used herein refers to a metal having a state in its valence (outermost electron shell) that can provide four electrons for covalent chemical bonding. Transition metals having an oxidation state of IV include germanium (Ge), cerium (Ce) and those 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 state of IV is selected from Ti, Ce, Zr, Hf, Ge, and combinations thereof. In a particular embodiment, the transition metal having an oxidation state of IV comprises Ti.

In one or more embodiments, the zeolitic framework material comprises MO₄/SiO₄/AlO₄Tetrahedra (where M is a tetravalent metal) and connected by a common oxygen atom to form a three-dimensional network. Isomorphously substituted tetravalent metals as tetrahedral atoms (MO)₄) Embedded in the zeolitic framework material. Isomorphously substituted tetrahedral units therefore form, together with the silicon and aluminum tetrahedral units, the framework of the zeolitic material. In particular embodiments, the tetravalent metal comprises titanium and the zeolitic framework material comprises TiO₄/SiO₄/AlO₄A tetrahedron. Thus, in one or more embodiments, the catalyst comprises a silicon and aluminum atom zeolitic framework wherein a portion of the silicon atoms are isomorphously substituted with titanium.

The isomorphously substituted zeolitic framework materials of one or more embodiments are based primarily on substitution of MO with MO₄/(SiO₄)/AlO₄The geometry of the voids formed by the rigid network of tetrahedra (where M is a tetravalent metal) is differentiated.

In one or more embodiments, the molecular sieve comprises SiO₄/AlO₄Tetrahedral and connected by common oxygen atoms to form a three-dimensional network. In other embodiments, the molecular sieve comprises SiO₄/AlO₄/PO₄A tetrahedron. The molecular sieve of one or more embodiments is based primarily on a zeolite composed of (SiO)₄)/AlO₄Or SiO₄/AlO₄/PO₄The geometry of the voids formed by the rigid network of tetrahedra. The entrance to the void is formed by 6, 8, 10 or 12 ring atoms, as far as the atoms forming the entrance opening are concerned. In one or more embodiments, the molecular sieve comprises a ring size of no greater than 12, including ring sizes of 6, 8, 10, and 12.

According to one or more embodiments, molecular sieves can be based on the framework topology used to identify the structure. Generally, any structure type of zeolite CAN be used, such as structure type 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, KFO, FAFER, FAU, FRA, GIS, GIU, GME, GON, GOO, HEU, IFR, IHV, LON, EPI, ERI, ESV, MOV, MAHO, MAIN, MAHO, MAIN, MA, 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, VNI, VSV, WIE, WEN, YUG, ZON, or combinations thereof.

In one or more embodiments, the molecular sieve comprises an 8-ring small pore aluminosilicate zeolite. As used herein, "pore" refers to a pore opening on the order of less than about 5 angstroms, e.g., -3.8 angstroms. The term "8-ring" zeolite refers to a zeolite having 8-ring pore openings and double six-ring secondary building units and having a cage structure resulting from the connection of the double six-ring building units by 4 rings. Zeolites are composed of secondary building blocks (SBUs) and composite building blocks (CBUs) and exhibit many different framework structures. The secondary building blocks contain up to 16 tetrahedral atoms and are achiral. The composite building block is not required to be achiral and does not have to be used to construct the entire skeleton. For example, one class of zeolites has a single 4-ring (s4r) composite structural unit in its framework structure. In the 4-ring, "4" refers to the positions of tetrahedral silicon and aluminum atoms, and oxygen atoms are located between the tetrahedral atoms. Other complex building blocks include, for example, single 6-ring (s6r) blocks, double 4-ring (d4r) blocks, and double 6-ring (d6r) blocks. The d4r unit is created by linking two s4r units. The d6r unit is created by linking two s6r units. In the d6r unit, there are 12 tetrahedral atoms. Zeolite structure types having d6r secondary building units include 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, and WEN.

In one or more embodiments, the molecular sieve comprises d6r units. Without wishing to be bound by theory, it is believed that in one or more embodiments, the d6r unit promotes NO⁺Is performed. Thus, in one or more embodiments, the molecular sieve has a structure type selected from the group consisting of 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. In other embodiments, the molecular sieve has a structure type selected from CHA, AEI, AFX, ERI, KFI, LEV, and combinations thereof. In still other embodiments, the molecular sieve has a structure type selected from CHA, AEI, and AFX. In one or more very specific embodiments, the molecular sieve has the CHA structure type.

The zeolite chabazite comprises a zeolite having the approximate formula: (Ca, Na)₂,K₂,Mg)Al₂Si₄O₁₂·6H₂Zeolites of O (e.g. hydrated calcium aluminium silicate) naturally occurring tectosilicate minerals. In D.W.Breck, John Wiley&Sons describes three synthetic forms of Zeolite chabazite in "Zeolite Molecular Sieves" published in 1973, which is incorporated herein by reference. The three synthetic forms reported by Breck are zeolite K-G described by Barrer et al in j.chem.soc., page 2822 (1956); zeolite D described in british patent No.868,846 (1961); and zeolite R described in U.S. patent No.3,030,181, which are incorporated herein by reference. The synthesis of another synthetic form of zeolite chabazite, SSZ-13, is described in U.S. Pat. No.4,544,538, which is incorporated herein by reference. One synthetic form of molecular sieve having the chabazite crystal structure, the synthesis of silicoaluminophosphate 34(SAPO-34), is described in U.S. Pat. nos.4,440,871 and No.7,264,789, which are incorporated herein by reference. A method of making another synthetic molecular sieve SAPO-44 having a chabazite structure is described in U.S. patent No.6,162,415, which is incorporated herein by reference.

In one or more embodiments, the molecular sieve may include all aluminosilicate, borosilicate, gallosilicate, MeAPSO, and MeAPO compositions. These include, but are not limited to SSZ-13, SSZ-62, natural chabazite, zeolite K-G, Linde D, Linde R, LZ-218, LZ-235, LZ-236, ZK-14, SAPO-34, SAPO-44, SAPO-47, ZYT-6, CuSAPO-34, CuSAPO-44 and CuSAPO-47.

The silica to alumina ratio of the aluminosilicate molecular sieve can vary over a wide range. In one or more embodiments, the molecular sieve has a molecular weight of from 2 to 300, including from 5 to 250; 5 to 200; 5 to 100; and a silica to alumina molar ratio (SAR) in the range of 5 to 50. In one or more specific embodiments, the molecular sieve has a molecular weight of from 10 to 200, from 10 to 100, from 10 to 75, from 10 to 60, and from 10 to 50; 15 to 100, 15 to 75, 15 to 60, and 15 to 50; silica to alumina molar ratios (SAR) in the range of 20 to 100, 20 to 75, 20 to 60, and 20 to 50. In a more specific embodiment, the molecular sieve has any of the above SAR ranges, the spherical particles of the molecular sieve have a median particle size in the range of about 0.5 to about 5 microns, more particularly about 1.0 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of about 100 to about 250 nanometers.

Isomorphous substitution of silicon with a tetravalent metal affects the silica to alumina ratio of the zeolitic framework material. In one or more embodiments, the molecular sieve is isomorphously substituted with a tetravalent metal and has a molecular weight from 2 to 300, including from 5 to 250; 5 to 200; 5 to 100; and a silica to alumina molar ratio (SAR) in the range of 5 to 50. In one or more specific embodiments, the first and second molecular sieves independently have a molecular weight of from 10 to 200, from 10 to 100, from 10 to 75, from 10 to 60, and from 10 to 50; 15 to 100, 15 to 75, 15 to 60, and 15 to 50; silica to alumina molar ratios (SAR) in the range of 20 to 100, 20 to 75, 20 to 60, and 20 to 50.

In embodiments where the molecular sieve is isomorphously substituted with a tetravalent metal, the ratio of tetravalent metal to alumina can vary over a very wide range. Note that this ratio is an atomic ratio and not a molar ratio. In one or more embodiments, the ratio of tetravalent metal to alumina ranges from 0.0001 to 10000, including from 0.0001 to 10000, from 0.001 to 1000, and from 0.01 to 10. In other embodiments, the ratio of tetravalent metal to alumina is in the range of 0.01 to 10, including 0.01 to 10, 0.01: to 5, 0.01 to 2, and 0.01 to 1. In particular embodiments, the ratio of tetravalent metal to alumina ranges from 0.01 to 2.

In embodiments where the molecular sieve is isomorphously substituted with a tetravalent metal, the tetravalent metal comprises titanium, and the ratio of titanium dioxide to alumina is in the range of 0.0001 to 10000, including 0.0001 to 10000, 0.001 to 1000, and 0.01 to 10. In other embodiments, the ratio of titanium dioxide to alumina is in the range of 0.01 to 10, including 0.01 to 10, 0.01: to 5, 0.01 to 2, and 0.01 to 1. In particular embodiments, the ratio of titania to alumina is in the range of 0.01 to 2.

The ratio of silica to tetravalent metal may vary over a wide range. Note that this ratio is an atomic ratio and not a molar ratio. In one or more embodiments, the ratio of silica to tetravalent metal ranges from 1 to 100, including from 1 to 50, from 1 to 30, from 1 to 25, from 1 to 20, from 5 to 20, and from 10 to 20. In a specific embodiment, the ratio of silica to tetravalent metal is about 15. In one or more embodiments, the tetravalent metal comprises titanium, and the ratio of silicon dioxide to titanium dioxide ranges from 1 to 100, including from 1 to 50, from 1 to 30, from 1 to 25, from 1 to 20, from 5 to 20, and from 10 to 20. In a specific embodiment, the ratio of silica to titania is about 15.

Promoter metals:

the molecular sieve of one or more embodiments may then 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 varies depending on the structure type of the zeolitic material, but generally involves the combination of several components (e.g., silica, alumina, phosphorous, alkali metals, organic templates, etc.) to form a synthetic gel, which is then hydrothermally crystallized to form the final product. The structure directing agent can be an organic (i.e., tetraethylammonium hydroxide (TEAOH)) or inorganic cation (i.e., Na)⁺Or K⁺) In the form of (1). During crystallization, the tetrahedral units organize around the SDA to form the desired framework, and the SDA is typically embedded within the pore structure of the zeolite crystals. At one orIn various embodiments, crystallization of the molecular sieve may be obtained by the addition of structure directing agents/templates, nuclei, or elements. In some cases, crystallization may be performed at a temperature of less than 100 ℃.

As used herein, "promoted" refers to a component that is intentionally added to a molecular sieve, not an impurity inherent in the molecular sieve. Thus, the promoter is intentionally added to increase the activity of the catalyst as compared to a catalyst without the intentionally added promoter. To facilitate SCR of nitrogen oxides, 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 particular embodiments, the molecular sieve is promoted with Cu, Fe, and combinations thereof.

The promoter metal content of the molecular sieve is reported to be at least about 0.1 wt.% in one or more embodiments, calculated as the oxide, on a volatile-free basis. In particular embodiments, the promoter metal comprises Cu, and the Cu content, calculated as CuO, is up to about 10 wt.%, including 9, 8, 7,6, 5, 4,3, 2, 1, 0.5, and 0.1 wt.%, reported on a volatile-free oxide basis, in each case based on the total weight of the calcined molecular sieve. In particular embodiments, the Cu content, calculated as CuO, is from about 2 to about 5 weight percent. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 2 to 300, the Cu content can be reported on a volatile-free oxide basis in the range of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%, in each case based on the total weight of the calcined molecular sieve. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 5 to 250, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 5 to 200, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 5 to 100, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having an SAR of 5 to 50, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 10 to 250, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 10 to 200, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 10 to 100, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 10 to 75, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 10 to 60, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 10 to 50, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 15 to 100, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having an SAR of 15 to 75, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 15 to 60, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having an SAR of 15 to 50, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 20 to 100, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having an SAR of 20 to 75, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having a SAR of 20 to 60, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

For a particular molecular sieve having an SAR of 20 to 50, the Cu content can be reported on a volatile-free oxide basis, based in each case on the total weight of the calcined molecular sieve, of 0.1 to 10 wt.%, or 0.5 to 8 wt.%, or 0.8 to 6 wt.%, or 1 to 4 wt.%, or even 2 to 3 wt.%. In a more specific embodiment, the molecular sieve has this particular combination of SAR and Cu content, the spherical particles of the molecular sieve have a median particle size in the range of from about 0.5 to about 5 microns, more particularly from about 1.2 to about 3.5 microns, and the individual crystals of the molecular sieve have a crystal particle size in the range of from about 100 to about 250 nanometers.

Without intending to be bound by theory, it is believed that when the molecular sieve is isomorphously substituted with a tetravalent metal, the tetravalent metal is embedded in the zeolite framework as tetrahedral atoms so as to be structurally and electronically intimately coupled to the active promoter metal centers. In one or more embodiments, the promoter metal may be ion exchanged into the isomorphously substituted molecular sieve. In a specific embodiment, the copper ions are exchanged into an isomorphously substituted molecular sieve. The metal may be exchanged after the preparation or manufacture of the isomorphously substituted molecular sieve.

Porosity and particle shape and size:

in one or more embodiments, the catalyst material comprises spherical particles comprising agglomerates of molecular sieve crystals. The term "agglomerate" or "agglomeration" as used herein refers to a cluster or collection of primary particles (i.e., crystals of the molecular sieve).

In one or more embodiments, the spherical particles have a median particle size in the range of about 0.5 to about 5 microns, including 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.75, 2.0, 2.25, 2.5, 2.75, 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 by microscopy, more particularly by Scanning Electron Microscopy (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, including about 1.2 to about 3.5 microns. The term "median particle size" as used herein refers to the median cross-sectional diameter of the spherical particles. 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, individual crystals of the molecular sieve have a crystal size in the range of about 1 to about 250 nanometers, including 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 nanometers. The crystal size of individual crystals of the molecular sieve can be measured by microscopy, more particularly by Scanning Electron Microscopy (SEM). In particular embodiments, individual crystals of the molecular sieve have a crystal size in the range of from about 100 to about 250 nanometers or from about 100 to about 200 nanometers. Generally, there is no particular limitation on the shape of the individual crystals of the molecular sieve concerned. In one or more embodiments, the individual crystals of the molecular sieve, without limitation, can be cubic, spherical, platelet-shaped, acicular, isometric, octahedral, tetrahedral, hexahedral, orthorhombic, trigonal, etc., or any combination thereof.

Without intending to be bound by theory, it is believed that in one or more embodiments, the catalyst material has a monodisperse snowball structure. As used herein, monodisperse snowballs refer to an arrangement or aggregation of a plurality of individual molecular sieve crystals into substantially spherical bodies. The term "monodisperse" as used herein means that the individual molecular sieve crystals are uniform and approximately equal in size, having a crystal size in the range of from about 1 to about 250 nanometers. Monodisperse snowballs are similar to individual snow particles that form a snowball. In other embodiments, the catalyst material has a spherical snowball structure in which 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 the molecular sieve form microagglomerates (microagglomerates), which subsequently form large agglomerated (macroagglomerated) snowball structures. In one or more embodiments, the microagglomerates have a size of less than 1.0 micron, including less than 0.9, less than 0.8, less than 0.7, less than 0.6, less than 0.5, less than 0.4, less than 0.3, less than 0.2, and less than 0.1 microns, and the large agglomerated spherical snowball structures have a particle size of about 0.5 to about 5 microns, including about 1.2 to about 3.5 microns. The size of the microagglomerates can be measured by microscopy, more particularly by Scanning Electron Microscopy (SEM).

In one or more embodiments, the molecular sieve comprises a isomorphously substituted zeolitic framework material, wherein a portion of the silicon atoms are isomorphously substituted with a tetravalent metal. Isomorphously substituted zeolitic framework materials according to embodiments of the present invention may be provided as a washcoat. The isomorphously substituted zeolitic framework materials provide a washcoat that is generally very porous. The particle size of the isomorphously substituted zeolitic framework material is typically in the range of from 1 to 2 microns. Additionally, without intending to be bound by theory, it is believed that the presence of tetravalent metals, particularly titanium, controls the zeolite crystals to produce a monodisperse snowball structure. In other words, the molecular sieve comprises an agglomeration of molecular sieve crystals isomorphously substituted with a tetravalent metal. It will be apparent to those of ordinary skill in the art that the particles of the molecular sieve comprising the isomorphously substituted zeolitic framework material are significantly larger than the molecular sieve having the CHA structure made according to conventional methods known in the art. Such conventionally prepared molecular sieves are known to have particle sizes of less than about 0.5 microns.

The structure of the monodisperse snowball of one or more embodiments is more readily understood by the schematic illustration in fig. 1. Referring to fig. 1, an exemplary embodiment of a catalyst material is shown. The catalyst material comprises spherical particles 10 comprising agglomerated crystals 20. The spherical particles 10 have a particle size S of about 0.5 to about 5 microns, including about 1.2 to about 3.5 microns_p. The individual crystals 20 of the molecular sieve have a crystal size S of about 1 to about 250 nanometers, including in the range of about 100 to 250 nanometers or 100 to 200 nanometers_c. In one or more embodiments, individual crystals 20 of the molecular sieve form microagglomerates 30, which subsequently form large agglomerated snowball structures 10. The microagglomerates 30 have a size S less than 1.0 micron and greater than 0 micron_m。

As is apparent to one of ordinary skill in the art, the spherical particles of the crystals of the molecular sieve are clearly different in structure from molecular sieves having the CHA structure that do not have an agglomerated snowball structure.

The catalyst material according to embodiments of the invention may be provided in the form of a powder or spray material from separation techniques including decantation, filtration, centrifugation or spraying.

In general, the powder or spray material can be shaped without any other compound, for example by suitable compaction, to obtain a moulding of the desired geometry, for example a flake, a cylinder, a sphere, etc.

For example, the powder or spray material is mixed with or coated with a suitable modifier as is well known in the art. For example, modifiers such as silica, alumina, zeolites, or refractory binders (e.g., zirconium precursors) may be used. The powder or spray material, optionally after mixing or coating with a suitable modifier, is slurried, e.g., with water, and deposited on a suitable high temperature resistant support, e.g., a flow-through honeycomb substrate support or a wall-flow honeycomb substrate support.

Catalyst materials according to embodiments of the invention may also be provided in the form of extrudates, pellets, flakes or particles of any other suitable shape for use as a packed bed of particulate catalyst or as shaped pieces such as plates, saddles, tubes and the like.

SCR catalyst composites:

government regulations require the use of NO for light and heavy vehicles_xAnd (3) emission reduction technology. NO Using Ammonia_xSelective Catalytic Reduction (SCR) for NO control_xEfficient and mainstream emission control techniques. In one exemplary embodiment, an SCR catalyst composite is provided having an improved ammonia storage capacity at 400 ℃ and above and an ability to facilitate the storage of ammonia rather than water. Although the catalyst material of one or more embodiments may be used in any lean burn engine, including diesel engines, lean burn gasoline direct injection engines, and compressed natural gas engines, in particular embodiments the catalyst material is used in lean burn Gasoline Direct Injection (GDI) engines.

Embodiments of the invention relate to a catalyst composite comprising an SCR catalyst material and an ammonia storage material comprising a transition metal having an oxidation state IV. The ammonia storage material is effective for storing ammonia at 400 ℃ and above, and has a minimum NH of 0.1g/L at 400 ℃₃And (4) storing quantity. In one or more embodiments, the SCR catalyst material selectively promotes the reaction of ammonia and nitrogen oxides to form nitrogen and H within a temperature range of 150 ℃ to 600 ℃₂O, and the ammonia storage material is effective for storing ammonia at 400 ℃ and higher, having a minimum NH of 0.1g/L at 400 ℃₃And (4) storing quantity. It has surprisingly been found that the catalyst composite is particularly suitable for use in exhaust gas purification catalyst components, in particular as an SCR catalyst.

According to one or more embodiments, the SCR catalyst composite comprises an SCR catalyst material and an ammonia storage material. In one or more embodiments, the SCR catalyst material comprises one or more of a molecular sieve, a mixed oxide, and an activated refractory metal oxide support.

In one or more embodiments, the SCR catalyst material comprises a molecular sieve. According to one or more embodiments, the ammonia storage material comprises a transition metal having an oxidation state of IV. Without wishing to be bound by theory, it is believed that the presence of elements having the oxidation state of form IV helps to improve ammonia storage at high temperatures. In one or more embodiments, the transition metal having an oxidation state of IV can be in the form of an oxide or inherently embedded in the SCR catalyst material. The term "transition metal having an oxidation state of IV" as used herein refers to a metal having a state in its valence (outermost electron shell) that can provide four electrons for covalent chemical bonding. Transition metals having an oxidation state of IV include germanium (Ge), cerium (Ce) and those 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 state of IV is selected from Ti, Ce, Zr, Hf, Ge, and combinations thereof. In a particular embodiment, the transition metal having an oxidation state of IV comprises Ti.

One or more embodiments of the present invention relate to an SCR catalyst composite comprising an SCR catalyst material and an ammonia storage material comprising a transition metal having an oxidation state IV, wherein the SCR catalyst material and the ammonia storage material are in a layered arrangement or relationship. In one or more embodiments, the ammonia storage material may be in any flexible form, such as layered or homogeneously mixed with the SCR catalyst material, and inherently implemented within the same SCR catalyst material. 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 (washcoated) onto the substrate, and then the ammonia storage material is washcoated (washcoated) in a layer overlying the SCR catalyst material.

In other embodiments, the SCR catalyst material and the ammonia storage material are arranged in a zoned configuration. In one or more embodiments, the SCR catalyst material and the ammonia storage material are arranged in a laterally zoned configuration, with the ammonia storage material being upstream of the SCR catalyst material. The term "laterally zoned" as used herein refers to the position of the SCR catalyst material and the ammonia storage material relative to each other. Lateral refers to side-by-side such that the SCR catalyst material and the ammonia storage material are located one beside the other and the ammonia storage material is upstream of the SCR catalyst material. The terms "upstream" and "downstream" as used herein refer to the engine being at an upstream location and the exhaust pipe and any pollution abatement articles such as filters and catalysts being downstream of the engine relative to the direction according to the flow direction of the engine exhaust gas stream from the engine to the exhaust pipe. In accordance with one or more embodiments, the laterally partitioned ammonia storage material and the SCR catalyst material may be disposed on the same or a common substrate or separate substrates from each other.

In other embodiments, the SCR catalyst material is ion exchanged with the ammonia storage material.

In one or more embodiments, the transition metal having the oxidation state IV may be present in the oxide form, may be ion exchanged, or may be isomorphously substituted at the zeolite framework positions when in a layered or zoned arrangement. For example, in particular embodiments, the transition metal having an oxidation state of IV comprises titanium. In such embodiments where the transition metal having the oxidation state IV is present in the oxide form, the ammonia storage material comprising the transition metal having the oxidation state IV is dispersed on the support material.

Referring to FIG. 2, an exemplary embodiment of a horizontally partitioned system is shown. The SCR catalyst composite 200 is shown in a laterally zoned arrangement, where the ammonia storage material 210 is located 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 defining an axial length L. In one or more embodiments, the substrate 230 generally comprises a plurality of channels 260 of a honeycomb substrate, wherein only one channel is shown in cross-section for clarity. The ammonia storage material 210 extends from the inlet end 240 of the substrate 230 less than the entire axial length L of the substrate 230. The length of the ammonia storage material 210 is labeled as a first region 210a in fig. 2. The ammonia storage material 210 comprises a transition metal having an oxidation state of IV. The SCR catalyst material 220 extends from the outlet end 250 of the substrate 230 less than the entire axial length L of the substrate 230. The length of the SCR catalyst material 220 is labeled as a second zone 220a in fig. 2. The SCR catalyst material 220 selectively promotes the reaction of ammonia and nitrogen oxides to form nitrogen and H within a temperature range of 150 ℃ to 600 ℃₂O, and the ammonia storage material 210 is effectively at a minimum NH of 0.00001g/L at 400 ℃ and above₃The reserves store ammonia.

It is to be appreciated that the lengths of the first region 210a and the second region 220a may be varied. In one or more embodiments, the first region 210a and the second region 220a can be equally long. In other embodiments, the first region may be 20%, 25%, 35%, or 40%, 60%, 65%, 75%, or 80% of the length L of the substrate, and the second region correspondingly covers the remainder of the length L of the substrate.

Referring to FIG. 3, another embodiment of a laterally zoned SCR catalyst composite 110 is shown. The SCR catalyst composite 110 is shown in a laterally zoned arrangement in which an ammonia storage material 118 is located upstream of the SCR catalyst material 120 on

separate substrates

112 and 113. The ammonia storage material 118 is located on the substrate 112 and the SCR catalyst material is located on another substrate 113. The

substrates

112 and 113 may be composed of the same material or different materials. The base 112 has an inlet end 122a and an outlet end 124a defining an axial length L1. The base 113 has an inlet end 122b and an outlet end 124b defining an axial length L2. In one or more embodiments,

substrates

112 and 113 generallyIncluding a number of channels 114 of the honeycomb substrate, of which only one is shown in cross-section for clarity. The ammonia storage material 118 extends the entire axial length L1 of the substrate 112 from the inlet end 122a of the substrate 112 to the outlet end 124 a. The length of the ammonia storage material 118 is labeled as a first region 118a in FIG. 3. The ammonia storage material 118 comprises a transition metal having an oxidation state of IV. The SCR catalyst material 120 extends the entire axial length L2 of the substrate 113 from the outlet end 124b of the substrate 113 to the inlet end 122 b. The SCR catalyst material 120 delimits a second zone 120 a. The length of the SCR catalyst material is labeled as second zone 20b in fig. 3. The SCR catalyst material 120 selectively promotes the reaction of ammonia and nitrogen oxides to form nitrogen and H within a temperature range of 150 ℃ to 600 ℃₂O, and the ammonia storage material 118 is effectively at a minimum NH of 0.00001g/L at 400 ℃ and above₃The reserves store ammonia. The lengths of

regions

118a and 120a may be varied as described for fig. 2.

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. Fig. 4A and 4B show a wall-flow filter substrate 35 having a plurality of channels 52. These channels are enclosed 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 channels are alternately plugged at the inlet end with inlet plugs 58 and at the outlet end with outlet plugs 60, thereby forming an opposite checkerboard pattern at the inlet 54 and outlet 56. Gas stream 62 enters through unplugged channel inlets 64, is blocked by outlet plugs 60, and diffuses through channel walls 53 (which are porous) to outlet side 66. Gas cannot pass back to the inlet side of the wall due to the inlet plug 58.

In one or more embodiments, the wall-flow filter substrate is composed of a ceramic-like material, such as cordierite, alpha-alumina, silicon carbide, silicon nitride, zirconia, mullite, spodumene, alumina-silica-magnesia or zirconium silicate, or a porous refractory metal. In other embodiments, the wall flow substrate is formed from a ceramic fiber composite. In particular embodiments, the wall flow substrate is formed from cordierite and silicon carbide. Such materials are capable of withstanding the environments, particularly high temperatures, encountered when treating exhaust streams.

In one or more embodiments, the wall-flow substrate comprises a thin porous-walled honeycomb monolith through which the fluid stream passes without causing excessive increases in backpressure or pressure across the article. Typically, the presence of a clean wall-flow article can cause a back pressure of 1 inch of water to 10 psig. The ceramic wall flow substrate used in the system is formed of a material having a porosity of at least 50% (e.g., 50 to 75%) with an average pore size of at least 5 microns (e.g., 5 to 30 microns). In one or more embodiments, the substrate has a porosity of at least 55% and has an average pore size of at least 10 microns. When substrates having these porosities and these average pore sizes are coated by the techniques described below, a sufficient amount of the catalyst composition can be loaded onto the substrate to achieve excellent NO_xThe conversion efficiency. These substrates maintain adequate exhaust flow characteristics, i.e., acceptable backpressure, despite the loading of the SCR catalyst. The disclosure of U.S. Pat. No.4,329,162 for suitable wall flow substrates is incorporated herein by reference.

Typical wall-flow filters for commercial use are formed with a lower wall porosity than the wall-flow filters used in the present invention, for example, about 35% to 50%. Typically, commercial wall flow filters have a pore size distribution that is typically extremely broad, with an average pore size of less than 17 microns.

The porous wall flow filters used in one or more embodiments are catalyzed, i.e., the elements have one or more SCR catalytic materials on or in the walls. The catalytic material may be present on only the inlet side, only the outlet side, both the inlet and outlet sides of the element walls, or the walls themselves may be constructed wholly or partially of catalytic material. The invention includes the use of one or more layers of catalytic material and combinations of one or more layers of catalytic material on the inlet and/or outlet walls of the element.

To coat a wall flow substrate with one or more embodiments of the SCR catalyst composite, the substrate is immersed vertically in a portion of the catalyst slurry such that the top of the substrate is just above the surface of the slurry. 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 was left in the slurry for about 30 seconds. The substrate is removed from the slurry and excess slurry is removed from the wall flow substrate as follows: first it is drained from the channel, then purged with compressed air (against the direction of slurry penetration), and then evacuated from the direction of slurry penetration. By using this technique, the catalyst slurry spreads over the (permeate) substrate walls, but does not plug the pores to such an extent that excessive back pressure builds up in the final substrate. As used herein, the term "throughout" when used to describe the dispersion of the catalyst slurry on the substrate means that the catalyst composition is dispersed throughout the substrate wall.

The coated substrate is typically dried at about 100 ℃ and calcined at higher temperatures (e.g., 300 to 450 ℃). After calcination, the catalyst loading can be determined by calculating the coated and uncoated weights of the substrate. It will be apparent to those skilled in the art that the catalyst loading can be varied by varying the solids content of the coating slip. Alternatively, repeated dipping of the substrate in the coating slurry may be performed, 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 within the SCR catalyst material. Thus, according to an embodiment of the invention, an SCR catalyst material comprises a molecular sieve having a framework of silicon (Si) and aluminum (Al) ions and optionally phosphorus (P) ions, wherein a portion of the silicon atoms are isomorphously substituted with an ammonia storage material comprising a transition metal having an oxidation state IV.

In one or more embodiments, an ammonia oxidation (AMOx) catalyst may be provided downstream of the SCR catalyst composite to remove any ammonia that escapes from the exhaust treatment system. In particular embodiments, the AMOx catalyst can comprise a platinum group metal, such as platinum, palladium, rhodium, or a combination thereof.

AMOx and/or SCR catalyst materials can be coated on a flow-through or wall-flow filter. If a wall flow substrate is used, the resulting system is capable of removing particulates along with the gaseous contaminants. The wall-flow filter substrate may be made of materials known in the art, such as cordierite, aluminum titanate, or silicon carbide. It is understood that the loading of the catalytic composition on the wall flow substrate depends on substrate properties such as porosity and wall thickness, and is generally lower than the loading on the flow-through substrate.

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

Generally, it is desirable to suppress NH₃Storage on zeolite SCR catalysts to obtain faster NO at highly dynamic engine operation_xAnd (5) response of conversion. Without wishing to be bound by theory, it is believed that with prior art SCR catalysts, reliance on weak NH in the pores of the zeolite due to the presence of relatively large amounts of competing water vapor₃Physical adsorption or Bronsted acidity of the unused exchange sites, it is not possible to achieve the desired high temperature NH₃And (4) storing.

Therefore, it is necessary to use NH capable of high temperature₃Storage and ability to distinguish NH on storage₃And H₂The second functional site of O, i.e., using Lewis acidity. It is believed that NH is due to₃Are nucleophilic (or more generally basic) in nature, and lewis acidity can provide additional NH₃Storage route. Accordingly, transition metals having different oxidation states can provide adjustable lewis acid strength. In general, the higher the oxidation state of the transition metal, the stronger the Lewis acidity is expected. It is therefore believed that transition metals having an oxidation state of IV will produce NH which can be stored at higher temperatures₃The catalyst material of (1).

In one or more embodiments, the SCR catalyst material comprises SiO-containing₄/AlO₄Tetrahedral molecular sieves. In one or more embodiments, the SCR catalyst material is isomorphously substituted with the ammonia storage material. In such embodiments, the SCR catalyst material comprises MO₄/SiO₄/AlO₄Tetrahedra (where M is a transition metal having an oxidation state of IV) and connected by a common oxygen atom to form a three-dimensional network. Isomorphously substituted transition metals having oxidation state IV as tetrahedral atoms (MO)₄) Embedded in a molecular sieve. Isomorphously substituted tetrahedral units are subsequently combined with silicon and aluminum tetrahedral unitsThe elements together form the framework of the molecular sieve. In particular embodiments, the transition metal having an oxidation state of IV comprises titanium, and the SCR catalyst material therefore comprises TiO₄/SiO₄/AlO₄A tetrahedron.

In other embodiments, the SCR catalyst material comprises SiO-containing₄/AlO₄/PO₄Tetrahedral molecular sieves. In one or more embodiments, the SCR catalyst material is isomorphously substituted with the ammonia storage material. In such embodiments, the SCR catalyst material comprises MO₄/SiO₄/AlO₄/PO₄Tetrahedra (where M is a transition metal having an oxidation state of IV) and connected by a common oxygen atom to form a three-dimensional network. Isomorphously substituted transition metals having oxidation state IV as tetrahedral atoms (MO)₄) Embedded in a molecular sieve. The isomorphously substituted tetrahedral units then form, along with the silicon, aluminum, and phosphorus tetrahedral units, the framework of the molecular sieve. In particular embodiments, the transition metal having an oxidation state of IV comprises titanium, and the SCR catalyst material therefore comprises TiO₄/SiO₄/AlO₄/PO₄A tetrahedron.

The isomorphously substituted molecular sieves of one or more embodiments are based primarily on substitution by MO₄/(SiO₄)/AlO₄The geometry of the voids formed by the rigid network of tetrahedra (where M is a transition metal having an oxidation state of IV) is distinguished.

In one or more embodiments, the molecular sieve of the SCR catalyst material has a structure type selected from any of the structure types described above. In one or more specific embodiments, the molecular sieve has a structure type selected from the group consisting of 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. In other embodiments, the molecular material has a structure type selected from the group consisting of MFI, BEA, CHA, AEI, AFX, ERI, KFI, LEV, and combinations thereof. In a very specific embodiment, the molecular sieve has a structure 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 an aluminosilicate zeolite type and has an AEI structure type, such as SSZ-39. In accordance with one or more embodiments, it is to be appreciated that by defining a molecular sieve by its structure type, it is intended to include that structure type and any and all homotypic framework materials having the same structure type, such as SAPO, AlPO, and MeAPO materials.

The silica to alumina ratio of the molecular sieve can vary over a wide range. In one or more embodiments, the molecular sieve has a molecular weight of from 2 to 300, including from 5 to 250; 5 to 200; 5 to 100; and a silica to alumina molar ratio (SAR) in the range of 5 to 50. In one or more specific embodiments, the molecular sieve has a molecular weight of from 10 to 200, from 10 to 100, from 10 to 75, from 10 to 60, and from 10 to 50; 15 to 100, 15 to 75, 15 to 60, and 15 to 50; silica to alumina molar ratios (SAR) in the range of 20 to 100, 20 to 75, 20 to 60, and 20 to 50.

The ratio of transition metal having the oxidation state IV to alumina can vary over a very wide range. In one or more embodiments, the ratio of transition metal having an IV oxidation state to alumina is in the range of 0.001 to 10000, including 0.001:10000, 0.001 to 1000, 0.01 to 10. In other embodiments, the ratio of transition metal having an oxidation state IV to alumina is in the range of 0.01 to 10, including 0.01 to 10, 0.01: to 5, 0.01 to 2, and 0.01 to 1. In particular embodiments, the ratio of transition metal having an oxidation state IV to alumina is in the range of 0.01 to 2.

In particular embodiments, the transition metal having an IV oxidation state comprises titanium, and the ratio of titanium dioxide to alumina is in the range of 0.001 to 10000, including 0.001:10000, 0.001 to 1000, 0.01 to 10. In other embodiments, the ratio of titanium dioxide to alumina is in the range of 0.01 to 10, including 0.01 to 10, 0.01: to 5, 0.01 to 2, and 0.01 to 1. In particular embodiments, the ratio of titania to alumina is in the range of 0.01 to 2. In a very specific embodiment, the ratio of titania to alumina is about 1.

The ratio of silica to transition metal having an oxidation state of IV may vary over a wide range. Note that this ratio is an atomic ratio and not a molar ratio. In one or more embodiments, the ratio of silica to transition metal having an oxidation state IV is in the range of 1 to 100, including 1 to 50, 1 to 30,1 to 25, 1 to 20, 5 to 20, and 10 to 20. In a specific embodiment, the ratio of silica to transition metal having an oxidation state of IV is about 15. In one or more embodiments, the transition metal having an oxidation state IV comprises titanium, and the ratio of silicon dioxide to titanium dioxide is in the range of 1 to 100, including 1 to 50, 1 to 30,1 to 25, 1 to 20, 5 to 20, and 10 to 20. In a specific embodiment, the ratio of silica to titania is about 15.

To facilitate SCR of nitrogen oxides, 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 particular embodiments, the SCR catalyst material is promoted with Cu, Fe, and combinations thereof.

The promoter metal content of the SCR catalyst material is reported to be at least about 0.1 wt.% in one or more embodiments, calculated as the oxide, on a volatile-free basis. In particular embodiments, the promoter metal comprises Cu, and the Cu content, calculated as CuO, is up to about 10 wt.%, including 9, 8, 7,6, 5, 4,3, 2, and 1 wt.%, reported on a volatile-free basis, in each case based on the total weight of the calcined SCR catalyst material. In particular embodiments, the Cu content, calculated as CuO, is from about 2 to about 5 weight percent.

Without intending to be bound by theory, it is believed that when the SCR catalyst material is isomorphously substituted with an ammonia storage material comprising a transition metal having an oxidation state IV, the transition metal having an oxidation state IV is embedded as tetrahedral atoms in the molecular sieve framework so as to be structurally and electronically intimately coupled to the active promoter metal center. In one or more embodiments, the promoter metal can be ion-exchanged into the SCR catalyst material. In particular embodiments, copper ions are exchanged into the SCR catalyst material. The metal may be exchanged after the SCR catalyst material is prepared or manufactured.

According to one or more embodiments, the SCR catalyst material comprises a mixed oxide. The term "mixed oxide" as used herein refers to an oxide containing cations of more than one chemical element or cations of a single element in several oxidation states. In one or more embodiments, the mixed oxide is selected from Fe/titanium dioxide (e.g., FeTiO)₃) Fe/alumina (e.g. FeAl)₂O₃) Mg/titanium dioxide (e.g. MgTiO)₃) Mg/alumina (e.g. MgAl)₂O₃) Mn/alumina (e.g. MnO)_x/Al₂O₃) Mn/Titania (e.g. MnO)_x/TiO₂) Cu/titanium dioxide (e.g. CuTiO)₃) Ce/Zr (e.g. CeZrO)₂) Ti/Zr (e.g. TiZrO)₂) Vanadium oxide/titanium dioxide (e.g. V)₂O₅/TiO₂) And mixtures thereof. In particular embodiments, the mixed oxide comprises vanadium oxide/titanium dioxide. The vanadium oxide/titanium dioxide may be replaced by tungsten (e.g. WO)₃) Activated or stabilised to provide V₂O₅/TiO₂/WO₃. In one or more embodiments, the SCR catalyst material comprises titania, on which vanadium oxide is dispersed. The vanadium oxide may be dispersed at a concentration of 1 to 10 weight percent, including 1, 2, 3, 4,5, 6,7, 8, 9, 10 weight percent. In a particular embodiment, tungsten for vanadium oxide (WO)₃) Activation or stabilization. Tungsten may be dispersed at concentrations of 0.5 to 10 weight percent, including 1, 2, 3, 3.4, 5, 6,7, 8, 9, and 10 weight percent. All percentages are on an oxide basis.

According to one or more embodiments, the SCR catalyst material comprises a refractory metal oxide support material. As used herein, the terms "refractory metal oxide support" and "support" refer to an underlying high surface area material upon which additional chemical compounds or elements are supported. The carrier particles have a particle size of greater than

And wide pore distribution. As defined herein, thisLike metal oxide supports do not include molecular sieves, particularly zeolites. In particular embodiments, high surface area refractory metal oxide supports may be used, such as alumina support materials, also known as "gamma alumina" or "activated alumina," which typically exhibit more than 60 square meters per gram ("m²Such activated aluminas are typically mixtures of gamma and phases of alumina, but may also contain significant amounts of η, kappa, and theta alumina phases₂Brunauer, Emmett, Teller methods for determining surface area by adsorption. BET type N may also be used₂Adsorption or desorption experiments determine pore diameter and pore volume.

One or more embodiments of the invention include a high surface area refractory metal oxide support comprising an activating compound selected from the group consisting of alumina, ceria, zirconia, silica, titania, silica-alumina, zirconia-alumina, titania-alumina, lanthana-zirconia-alumina, baria-lanthana-neodymia-alumina, alumina-chromia, alumina-ceria, zirconia-silica, titania-silica, or zirconia-titania, and combinations thereof. In one or more embodiments, the activated refractory metal oxide support is exchanged with a metal selected from the group consisting of Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag, and combinations thereof.

SCR activity:

in one or more embodiments, selective catalytic reduction materials comprising spherical particles comprising agglomerates of molecular sieve crystals are shown at 80000h^-1When the gas is inAt least 50% of aged NO at 200 ℃ measured at space velocity_xAnd (4) conversion rate. In a specific embodiment, the material is shown to be 80000h^-1At least 70% of aged NO at 450 ℃ measured at a gas hourly space velocity of_xAnd (4) conversion rate. More specifically, aged NO at 200 ℃_xA conversion of at least 55% and at least 75% at 450 ℃, and more specifically, aged NO at 200 ℃_xConversion of at least 60% and at least 80% at 450 ℃ at 500ppm NO, 500ppm NH₃、10％O₂、5％H₂O, balance N₂In the gas mixture of (2) at maximum NH₃-at steady state conditions under escape conditions 80000h^-1Is measured at a volume based gas hourly space velocity. The core (cores) was heated in a tube furnace at 10% H₂O、10％O₂The balance N₂In the gas stream of (2) at 4,000h^-1Is subjected to hydrothermal aging at 750 ℃ for 5 hours at the space velocity of (1).

SCR activity measurements have been described in the literature, see, for example, PCT application publication No. wo 2008/106519.

Further, according to one or more embodiments, the catalyst material is effective to reduce N₂And (4) O yield.

NO⁺Formation and ammonia storage:

in addition, according to one or more embodiments, the molecular sieve is effective for promoting NO, particularly when the molecular sieve comprises a isomorphously substituted zeolitic framework material of silicon and aluminum atoms wherein a portion of the silicon atoms are isomorphously substituted with a tetravalent metal⁺Is performed. Without wishing to be bound by theory, it is believed that the short range promoter metal (e.g., Cu) migration/hopping between the two six-membered ring mirrors is facilitated by the d6r units of the zeolitic framework material to generate the appropriate NO⁺D6r unit is promoting NO⁺An important factor in formation, which requires a stabilized coordination environment also provided by the d6r unit.

Further, according to one or more embodiments, particularly when the SCR catalyst composite comprises an SCR catalyst material and an ammonia storage material comprising a transition metal having an oxidation state IV, the SCR catalyst material selectively promotes ammonia and nitrogen oxides over a temperature range of 150 ℃ to 600 ℃Reacting to form nitrogen and H₂O, and the ammonia storage material is effective at a minimum NH of 0.00001g/L at 400 ℃ and above₃The reserves store ammonia. In one or more embodiments, the exhaust stream has an oxygen content of 0 to 30% and a water content of 1 to 20%. SCR catalyst composites according to one or more embodiments even at H₂Also adsorbing NH in the presence of O₃. The SCR catalyst composites of one or more embodiments exhibit significantly greater high temperature ammonia storage capacity than the reference SCR catalyst material and catalyst composite.

Water, also carrying a lone pair of electrons, as a nucleophile is the largest competitor to store ammonia at the bronsted acid sites. For NO generated during lean-burn period of lean-burn GDI engine_xEffective utilization, importantly increased chemisorption of NH₃Amount of NH adsorbed rather than physically₃Amount of the compound (A). Without intending to be bound by theory, it is believed that the lewis acidity of the transition metal having the oxidation state IV enhances the ability of the SCR catalyst composite to chemisorb ammonia. Thus, the SCR catalyst composite according to one or more embodiments has improved ammonia storage capacity at temperatures of about 400 ℃ and higher.

Substrate:

in one or more embodiments, the catalyst material may be applied to the substrate as a washcoat. The term "substrate" as used herein refers to a monolith onto which a catalyst is placed, typically in the form of a washcoat. The washcoat is formed by preparing a slurry having a specified catalyst solids content (e.g., 30-90 wt%) in a liquid medium, which is then coated onto a substrate and dried to provide a washcoat.

The term "washcoat" as used herein has its ordinary meaning in the art, i.e., a thin adherent coating of catalytic or other material applied to a substrate material (e.g., a honeycomb-type carrier element) that is sufficiently porous to allow the treated gas stream to pass therethrough.

In one or more embodiments, the substrate is a ceramic or metal having a honeycomb structure. Any suitable substrate may be used, such as a monolithic substrate of the type having fine parallel gas flow channels therethrough from an inlet or outlet face of the substrate, to open the channels to fluid flow therethrough. The channels, which are essentially straight paths from their fluid inlets to their fluid outlets, are defined by walls on which catalytic material is applied as a washcoat so that gases flowing through the channels contact the catalytic material. The flow channels of the monolithic substrate are thin-walled channels, which may have any suitable cross-sectional shape and size, such as trapezoidal, rectangular, square, sinusoidal, hexagonal, elliptical, circular, and the like. Such structures may contain from about 60 to about 900 or more gas inlet openings (i.e., cells) per square inch of cross-section.

The ceramic substrate may be made of any suitable high temperature resistant material, such as cordierite, cordierite-alpha-alumina, silicon nitride, zircon mullite, spodumene, alumina-silica-magnesia, zirconium silicate, sillimanite, magnesium silicate, zirconium, petalite, alpha-alumina, aluminosilicates, and the like.

Substrates suitable for use in catalysts of embodiments of the present invention may also be metallic in nature and composed of one or more metals or metal alloys. The metal substrate may be used in various shapes such as pellets, corrugated sheets or monoliths. Specific examples of metal substrates include heat-resistant base metal alloys, especially those having iron as the primary or major component. Such alloys may contain one or more of nickel, chromium, and aluminum, and the total amount of these metals may advantageously constitute at least about 15 wt.% of the alloy, such as about 10 to 25 wt.% chromium, about 1 to 8 wt.% aluminum, and about 0 to 20 wt.% nickel.

Preparation of catalysts and catalyst materials:

synthesis of conventional CHA-type molecular sieves

Molecular sieves having the CHA structure can be prepared according to various techniques known in the art, such as U.S. Pat. nos.4,544,538(Zones) and 6,709,644(Zones), which are incorporated herein by reference in their entirety.

Optionally NH₄Exchange to form NH₄-chabazite:

optionally, subjecting the resulting alkali metal zeolite to NH₄Exchange to form NH₄-chabazite. May be according to various techniques known in the artBy carrying out NH₄Ion exchange, e.g., Bleken, f.; bjorgen, m.; palumbo, l.; bordiga, S.; svell, s.; lillerud, k. -p.; and Olsbye, u.topics, in Catalysis 52, (2009), 218-.

Synthesis of snowball molecular sieve

Molecular sieves having a snowball morphology can be prepared from adamantyltrimethylammonium hydroxide (ADAOH), aqueous sodium hydroxide, aluminum isopropoxide powder, and colloidal silica.

Synthesis of isomorphously substituted zeolitic framework materials

In accordance with one or more embodiments, a method of synthesizing a selective catalytic reduction catalyst material comprising an isomorphously substituted zeolitic framework material is provided. In particular, the catalyst material comprises a zeolitic framework material comprising silicon and aluminum atoms, wherein a portion of the silicon atoms are isomorphously substituted with a tetravalent metal.

Generally, the sodium form of the isomorphously substituted zeolitic framework material may be synthesized from 0.03Al by autoclave hydrothermal synthesis₂O₃:SiO₂:0.07TiO₂:0.06Na₂O:0.08ATMAOH:2.33H₂O-gel composition preparation. The product was recovered by filtration and the template was removed by calcination. The final crystalline material can be characterized by x-ray diffraction studies.

The H-form can be prepared by calcination of the ammonia form via double NH with the sodium form₄NO₃And (4) exchanging and obtaining. At NH₄NO₃The Ti content does not change/stabilize during the exchange process.

Copper promoted isomorphously substituted zeolite frameworks can be prepared by using H form and Cu (OAc)₂Ion exchange is made to achieve the desired amount of promoter metal.

Synthesis of isomorphous substituted molecular sieve

In accordance with one or more embodiments, a method is provided for synthesizing an SCR catalyst composite comprising an SCR catalyst material comprising a molecular sieve isomorphously substituted with an ammonia storage material comprising a transition metal having an oxidation state IV. In particular, the SCR catalyst composite comprises 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 state IV of an ammonia storage material.

Generally, the sodium form of the isomorphously substituted molecular sieve can be synthesized from 0.03Al by autoclave hydrothermal synthesis₂O₃:SiO₂:0.07TiO₂:0.06Na₂O:0.08ATMAOH:2.33H₂O-gel composition preparation. The product was recovered by filtration and the template was removed by calcination. The final crystalline material can be characterized by x-ray diffraction studies.

Copper promoted isomorphously substituted molecular sieves can be prepared by using the H form and Cu (OAc)₂Ion exchange is made to achieve the desired amount of promoter metal.

Reduction of NO_xAnd an exhaust gas treatment system:

generally, the above-described zeolitic materials can be used as molecular sieves, adsorbents, catalysts, catalyst supports, or binders therefor. In one or more embodiments, the material is used as a catalyst.

Another aspect of the present invention relates to a method of catalyzing a chemical reaction in which spherical particles comprising agglomeration of molecular sieve crystals according to an embodiment of the present invention are used as catalytically active material.

Another aspect of the present invention relates to a method of catalyzing a chemical reaction wherein a zeolitic framework material isomorphously substituted with a tetravalent metal according to an embodiment of the present invention is used as a catalytically active material.

Another aspect of the invention relates to a method of catalyzing a chemical reaction, wherein an SCR catalyst composite comprising an SCR catalyst material and an ammonia storage material comprising a transition metal having an oxidation state IV according to an embodiment of the invention is used as a catalytically active material.

The catalytic material and catalyst composite are particularly useful as Nitrogen Oxides (NO)_x) Selective reduction (SCR), NH of₃Oxidation, in particular NH in diesel engine systems₃A escaping oxidized catalyst; for use in oxidation reactions, in particular embodiments, additional noble metal components (e.g., Pd, Pt) are added to the spherical particles including agglomeration of molecular sieve crystals.

One or more embodiments provide for the selective reduction of Nitrogen Oxides (NO)_x) The method of (1). In one or more embodiments, the method comprises contacting NO_xIs contacted with the catalyst material or catalyst composite of one or more embodiments. In particular, the selective reduction of nitrogen oxides is carried out in the presence of ammonia or urea, wherein a selective catalytic reduction catalyst material comprising spherical particles comprising agglomerates of molecular sieve crystals according to an embodiment of the present invention is used as the catalytically active material, wherein the spherical particles have a median particle size in the range of about 0.5 to about 5 microns.

Ammonia is the reductant of choice for stationary power stations, while urea is the reductant of choice for mobile SCR systems. Generally, SCR systems are integrated in exhaust gas treatment systems of vehicles and also generally contain the following main components: a selective catalytic reduction material according to an embodiment of the present invention comprising spherical particles comprising agglomerates of molecular sieve crystals, wherein the spherical particles have a median particle size in the range of from about 0.5 to about 5 microns; a urea storage tank; a urea pump; a urea metering system; urea injectors/nozzles; and a respective 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 of a lean-burn gasoline direct injection engine. In such cases, the SCR catalyst composite according to one or more embodiments acts as a passive ammonia-SCR catalyst and is capable of efficiently storing ammonia at temperatures of 400 ℃ and higher.

The term "stream" as used herein broadly refers to any combination of flowing gases that may contain solid or liquid particulates. The term "gaseous stream" or "exhaust stream" refers to a stream of gaseous constituents, such as exhaust gas of a lean-burn engine, which may contain entrained non-gaseous components, such as liquid droplets, solid particulates, and the like. The exhaust stream of a lean-burn engine typically further comprises combustion products, products of incomplete combustion, nitrogen oxides, combustible and/or carbonaceous particulate matter (soot), and unreacted oxygen and nitrogen.

The terms nitrogen oxide, NO, as used in embodiments of the present invention_xRefers to oxides of nitrogen, especially nitrous oxide (N)₂O), Nitric Oxide (NO), dinitrogen trioxide (N)₂O₃) Nitrogen dioxide (NO)₂) Dinitrogen tetroxide (N)₂O₄) Dinitrogen pentoxide (N)₂O₅) Nitrogen peroxide (NO)₃)。

Another aspect of the invention relates to an exhaust treatment system. In one or more embodiments, an exhaust gas treatment system includes an exhaust gas stream optionally containing a reductant, such as ammonia, urea, and/or a hydrocarbon, and in particular embodiments, ammonia and/or urea, and a selective catalytic reduction material comprising spherical particles comprising agglomerates of molecular sieve crystals, wherein the spherical particles have a median particle size in a range of from about 0.5 to about 5 microns. The catalyst material is effective to destroy at least a portion of the ammonia in the exhaust stream.

In one or more embodiments, the SCR catalyst material can be disposed on a substrate, such as a soot filter. The catalyzed or uncatalyzed soot filter may be upstream or downstream of the SCR catalyst material. In one or more embodiments, the system can further comprise a diesel oxidation catalyst. In particular embodiments, a diesel oxidation catalyst is located upstream of the SCR catalyst material. In other embodiments, a diesel oxidation catalyst and a catalyzed soot filter are upstream of the SCR catalyst material.

In particular embodiments, the exhaust gas is delivered from the engine to a downstream location in the exhaust system, and in more particular embodiments contains NO_xWhere the reductant is added and the exhaust stream with the added reductant is delivered to the SCR catalyst material.

For example, catalyzed soot filters, diesel oxidation catalysts and reductants are described in WO 2008/106519, which is incorporated herein by reference. In particular embodiments, the soot filter comprises a wall-flow filter substrate in which the channels are alternately plugged such that a gaseous stream entering the channel from one direction (the inlet direction) flows through the channel walls and exits the channel from the other direction (the outlet direction).

An ammonia oxidation (AMOx) catalyst may be provided downstream of the SCR catalyst material or catalyst composite of one or more embodiments to remove any ammonia that escapes from the system. In particular embodiments, the AMOx catalyst can comprise a platinum group metal, such as platinum, palladium, rhodium, or a combination thereof.

Such AMOx catalysts may be used in exhaust treatment systems that include an SCR catalyst. As discussed in commonly assigned U.S. patent No.5,516,497, the entire contents of which are incorporated herein by reference, a gaseous stream containing oxygen, nitrogen oxides, and ammonia may be passed sequentially over first and second catalysts, the first catalyst promoting the reduction of the nitrogen oxides, the second catalyst promoting the oxidation or other decomposition of excess ammonia. As described in U.S. patent No.5,516,497, the first catalyst may be an SCR catalyst comprising a zeolite and the second catalyst may be an AMOx catalyst comprising a zeolite.

AMOx and/or SCR catalyst compositions can be coated on a flow-through or wall-flow filter. If a wall flow substrate is used, the resulting system is capable of removing particulates along with the gaseous contaminants. The wall-flow filter substrate may be made of materials known in the art, such as cordierite, aluminum titanate, or silicon carbide. It is understood that the loading of the catalytic composition on the wall flow substrate depends on substrate properties such as porosity and wall thickness, and is generally lower than the loading on the flow-through substrate.

The invention will now be described with reference to the following examples. Before describing several exemplary embodiments of the invention, it is to be understood that the 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 of being carried out in various ways.

Examples

Comparative example 1 preparation of catalyst composition and article

CuCHA powder catalysts are prepared by chabazite crystallization using a synthesis gel containing ADAOH (trimethyl-1-adamantyl ammonium hydroxide), separation of the chabazite product, drying and calcination to remove the organic template (ADAOH). Water, ADAOH solution and aqueous sodium hydroxide solution were added to the makedown tank and mixed for several minutes. Then the aluminum source is added over 3-5 minutes. The colloidal silica was then added with stirring over 5 minutes. Mixing was continued for an additional 30 minutes to produce a viscous gel of uniform composition. The gel was transferred to an autoclave. The autoclave was heated to 170 ℃ and crystallization was continued for 18 hours while maintaining stirring. Before discharge, the reactor was cooled to <50 ℃ and vented to atmospheric pressure. After hydrothermal crystallization, the resulting suspension had a pH of 11.5. The suspension was mixed with deionized water and filtered through a ceramic suction filter. The wet product was then heated in air to a temperature of 120 ℃ for 4 hours. The dried product was then calcined further in air at 600 ℃ for 5 hours to remove the template and ensure that the C content was less than 0.1 wt%.

As can be observed in the crystal morphology SEM image in fig. 5, the as-synthesized material (comparative example 1) had no agglomerated morphology as determined by SEM analysis (secondary electron imaging) at 5000 x.

The calcined product is then ready for ion exchange with Cu to obtain a metal-containing catalyst.

The ion exchange reaction between Na-form CHA and copper ions was carried out by stirring the slurry at about 60 ℃ for about 1 hour. The resulting mixture was then filtered to provide a filter cake which was washed in triplicate with deionized water until the filtrate was clear and colorless, and the washed sample was dried.

The resulting CuCHA catalyst contains approximately 3 to 3.5 wt% CuO as determined by ICP analysis. CuCHA slurry was prepared to 40% target solids. The slurry was milled and the binder (containing 30% ZrO) of zirconium acetate in dilute acetic acid was stirred₂) Is added to the slurry.

The slurry was coated onto a 1 "Dx 3" L honeycomb ceramic core having a pore density of 400cpsi (pores per square inch) and a wall thickness of 6.5 mil. The coated core was dried at 110 ℃ for 3 hours and calcined at approximately 400 ℃ for 1 hour.The coating process is repeated once to obtain 2-3g/in³Target washcoat loading.

Example 2

The 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 ℃ and crystallization was continued for 30 hours while maintaining stirring. Before discharge, the reactor was cooled to <50 ℃ and vented to atmospheric pressure. After hydrothermal crystallization, the resulting suspension had a pH of 12.0. The suspension was mixed with deionized water and filtered through a ceramic suction filter. The wet product was then heated in air to a temperature of 120 ℃ for 4 hours. The dried product was then calcined further in air at 600 ℃ for 5 hours to remove the template and ensure that the C content was less than 0.1 wt%.

As can be observed in the crystal morphology SEM image in fig. 6, the as-synthesized snowball material (example 2) has a characteristic spherical secondary structure of 1-2 microns in diameter as determined by SEM analysis (secondary electron imaging) at 5000 x. The individual crystals of the molecular sieve have a crystal size in the range of about 100 to 200 nanometers.

Example 3 Cu Co-catalysis

The ion exchange reaction between Na form CHA of example 2 and copper ions was carried out by stirring the slurry at about 60 ℃ for about 1 hour. The resulting mixture was then filtered to provide a filter cake which was washed in triplicate with deionized water until the filtrate was clear and colorless, and the washed sample was dried.

The resulting CuCHA catalyst contains approximately 1.5 to 4 wt% CuO as determined by ICP analysis. CuCHA slurry was prepared to 40% target solids. The slurry was milled and the binder (containing 30% ZrO) of zirconium acetate in dilute acetic acid was stirred₂) Is added to the slurry.

EXAMPLE 4 preparation of the washcoat

The example 3 slurry was then coated onto a substrate to 2.1g/in³Washcoat loading. The washcoat was dried under air at 130 ℃ for 5 minutes. After the final coating, the substrate is calcined 1 at 450 ℃And (4) hours.

Example 5 CuO Loading Studies

By adding 500ppm NO, 500ppm NH₃、10％O₂、5％H₂O, balance N₂Was added to a steady state reactor containing a 1 "D x 3" L catalyst core and the nitrogen oxide Selective Catalytic Reduction (SCR) efficiency and selectivity of the fresh catalyst core was measured. The reaction time is 80,000hr^-1Is carried out across a temperature range of from 150 ℃ to 460 ℃.

The sample was at 10% H₂Hydrothermal aging in the presence of O at 750 ℃ for 5 hours, followed by measurement of nitrogen oxide SCR efficiency and selectivity by the same method as described above for SCR evaluation on fresh catalyst cores.

FIG. 7 shows NO_xBar graph of conversion (%) vs CuO loading (% by weight).

FIG. 8 shows N₂Bar graph of O production (ppm) vs CuO loading (% by weight).

Example 6-NO_xConversion rate

FIG. 9 is a graph showing the NO of the catalyst of the invention of example 3 with the catalyst of example 1 (comparative) vs having 3.2% CuO_xGraph of conversion (%) vs temperature (. degree. C.).

FIG. 10 is a graph showing the N of the catalyst of the invention of example 3 with the catalyst of example 1 (comparative) vs having 3.2% CuO₂Graph of O production (ppm) vs temperature (deg.C).

FIG. 11 is a graph showing that the catalyst of example 1 (comparative) vs. example 3 with 3.2% CuO according to the invention at 20ppm NH₃NO under escape_xHistogram of conversion (%). The catalyst of example 3 showed significantly higher NH at 20ppm₃NO under escape_xConversion (approximately 15% higher) indicating improved transient performance during engine test conditions.

As shown in FIGS. 9-11, the snowball morphology results in an SCR catalyst material with improved NO compared to an SCR catalyst material without snowball morphology_xConversion efficiency and lower N₂And (4) O yield.

Isomorphous substituted molecular sieve

Example 7

From 0.03Al₂O₃:SiO₂:0.07TiO₂:0.06Na₂O:0.08ATMAOH:2.33H₂O-gel composition isomorphously substituted zeolite material (Na- [ Ti ] was prepared by autoclave hydrothermal synthesis at 155 deg.C for 5 days]CHA). The product was recovered by filtration and the template was removed by calcination at 600 ℃ for 5 hours. The final crystalline material had an X-ray powder diffraction pattern indicating>90% CHA phase, silica/alumina ratio (SAR) by XRF 25.

Example 8

By NH₄-[Ti]CHA (which passes NH)₄NO₃(2.4M) with the material of example 7 (Na- [ Ti ] Ti]Double exchange of CHA)) at 500 c (4 hours) to prepare an isomorphously substituted zeolitic material (H- [ Ti) by calcination]CHA). Ti content in NH₄NO₃The exchange was unchanged, 4.3% vs. 4.5%.

Example 9 comparison

The zeolitic material H-CHA was prepared according to the method of example 7 (HTi) CHA, but without the addition of Ti to the synthesis gel.

Example 10

By using the material of example 8 (H- [ Ti ] Ti]CHA) and Cu (OAc)₂(0.06M) preparation of copper-promoted isomorphously substituted zeolitic materials (Cu2.72- [ Ti ] by ion exchange at 50 deg.C (2 hours)]CHA) which exhibits a Cu content (ICP) of 2.72%.

Example 11

By using the material of example 9 (H- [ Ti ] Ti]CHA) and Cu (OAc)₂(0.125M) preparation of copper-promoted isomorphously substituted zeolitic materials (Cu3.64- [ Ti-Ti) by ion exchange at 50 deg.C (2 hours)]CHA) which exhibits a Cu content (ICP) of 3.64%.

Example 12 comparison

A standard copper promoted zeolitic material (cu2.75-CHA) was prepared at a Cu content (2.75%) comparable to example 9 according to the method provided in u.s.8404203b2. This material is provided as a reference for a reference.

Example 13 comparative

A standard copper promoted zeolitic material (cu3.84-CHA) was prepared at a Cu content (3.84%) comparable to example 10 according to the method provided in u.s.8404203b2. This material is provided as a reference for an aging reference.

Example 14

Incorporation of Ti at the tetrahedral site was determined by a gradient of 940-980 cm^-1Fingerprint confirmation of skeletal stretching (Ti-O-Si) involving Ti as shown in FIG. 12.

Example 15

The increased framework acidity due to the higher valence framework Ti (IV) is also contributed by increased NO in addition to fingerprint vibrations from the stretching of the framework involving Ti⁺The strength (its formation requires strong lewis acidity) is confirmed as shown in fig. 13.

Example 16

Exchange of Cu into isomorphous substituted zeolitic materials [ Ti ]]The acid sites of CHA, provided with the compounds of examples 10 and 11, did not affect NO⁺Is performed. As shown in FIG. 14, the material of example 10 (Cu2.72- [ Ti ] Ti]CHA) showed superior generation of more NO in the equilibrium state as compared to unmodified comparative example 12(Cu2.75-CHA)⁺The ability of the cell to perform. Taking into account NO⁺For nucleophiles, e.g. NH₃Is determined in example 10(Cu- [ Ti ] is]The significant reactivity boost at low temperatures (e.g. 200 ℃) observed in CHA) is due to the improved NO on the catalyst⁺Generation and retention.

Example 17

As can be observed in the SEM image in fig. 15, [ Ti ] CHA in as-synthesized state (example 8) has a characteristic secondary structure as spheres of 1-2 microns in diameter, as determined by SEM analysis (secondary electron imaging) at 5000 x.

Example 18

The material of example 10(Cu- [ Ti ] was heated]CHA) at 2.1g/in³Is wash coated on a flow-through ceramic substrate. Typical SCR test conditions include simulated diesel exhaust (500ppm NO, 500ppm NH)₃、10％O₂、5％H₂O and the balance N₂) And a temperature point from 200 ℃ to 600 ℃. Monitoring of NO and NH at various temperatures by FTIR₃And (4) conversion rate. If desired, exposure to 10% H at 750 deg.C₂Aging conditions for 5 hours under O to evaluate long-term hydrothermal durability.

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

Example 19

The porosity and particle size of this material are shown in fig. 19. As shown in FIG. 19, mercury intrusion measurements show that the washcoat formed from Cu- [ Ti ] CHA (example 10) has a pore distribution that is more prone to larger pores than the unmodified Cu-CHA (example 12).

In addition to the enhanced porosity of the washcoat, the as-synthesized Cu- [ Ti ] CHA produces a particle size significantly larger than that of standard copper-promoted zeolite materials.

Example 20

Catalyst Cu- [ Ti-]CHA at 2.1g/in³Is wash coated on a flow-through ceramic substrate. Typical SCR test conditions include simulated diesel exhaust (500ppm NO, 500ppm NH)₃、10％O₂、5％H₂O and the balance N₂) And a temperature point from 200 ℃ to 600 ℃. Monitoring of NO and NH at various temperatures by FTIR₃And (4) conversion rate. If desired, exposure to 10% H at 750 deg.C₂Aging conditions for 5 hours under O to evaluate long-term hydrothermal durability.

As shown in fig. 16, by means of a skeleton Ti (solid)Example 10), the SCR performance at 200 ℃ is significantly improved compared to a similar sample without Ti at equivalent Cu% (example 6), and NO high temperature (600 ℃) NO is observed_xSacrifice of conversion efficiency.

Example 21

As shown in FIG. 17, the high Cu content (e.g. Cu%>2.5% @ SAR ═ 30) leads to the formation of CuO after hydrothermal aging at high temperatures, which actively consumes NH₃So that the SCR performance at the high temperature end is degraded. The presence of skeletal Ti (example 11) helps to mitigate NH in the high temperature region of the high copper-loaded samples₃And (4) consumption.

Example 22

Isomorphously substituted zeolite material (Na- [ Ti ] AEI) was prepared in analogy to the material of example 7. The product was recovered by filtration and the template was removed by calcination at 600 ℃ for 5 hours.

Example 23

By NH₄-[Ti]AEI (which passes through NH)₄NO₃(2.4M) with the material of example 21 (Na- [ Ti ]]Double exchange of AEI) at 500 ℃ for 4 hours to prepare an isomorphously substituted zeolitic material (H- [ Ti ] Ti]AEI)。

Example 24

By using the material of example 22 (H- [ Ti ]]AEI) and Cu (OAc)₂(0.06M) preparation of copper-promoted isomorphously substituted zeolitic materials (Cu- [ Ti ] by ion exchange at 50 deg.C (2 hours)]AEI)。

Example 25

Isomorphous substituted zeolite material (Na- [ Ti ] AFX) was prepared similarly to the material of example 7. The product was recovered by filtration and the template was removed by calcination at 600 ℃ for 5 hours.

Example 26

By NH₄-[Ti]AFX (by NH)₄NO₃(2.4M) with the material of example 24 (Na- [ Ti ]]Double exchange of AFX) at 500 ℃ for the preparation of isomorphously substituted zeolitic materials (H- [ Ti ] Ti]AFX)。

Example 27

By using the material of example 25 (H- [ Ti ] Ti]AFX) and Cu (OAc)₂(0.06M) preparation of copper-promoted isomorphously substituted zeolitic materials by ion exchange at 50 deg.C (2 hours)(Cu-[Ti]AFX)。

Example 28

From 0.03Al₂O3:SiO₂:0.07TiO₂:0.06Na₂O:0.08ATMAOH:2.33H₂O-gel composition isomorphously substituted zeolite material (Na- [ Ti ] was prepared by autoclave hydrothermal synthesis at 155 deg.C for 5 days]CHA). The product was recovered by filtration and the template was removed by calcination at 600 ℃ for 5 hours. The final crystalline material had an X-ray powder diffraction pattern indicating>90% CHA phase, SAR 25 by XRF. Other SAR's, e.g. 20, can also be obtained by appropriate adjustment of the Si/Al ratio in the starting gel.

Example 29

By NH₄-[Ti]CHA (which passes NH)₄NO₃(2.4M) with the Material of example 27 (Na- [ Ti ]]Double exchange of CHA)) at 500 c (4 hours) to prepare an isomorphously substituted zeolitic material (H- [ Ti) by calcination]CHA). Ti content in NH₄NO₃The exchange was unchanged, 4.3% vs. 4.5%.

Example 30

The zeolitic material H-CHA was prepared according to the methods of examples 28 and 29, but without the addition of Ti to the initial synthesis sol-gel used for the hydrothermal crystallization of the zeolite.

Example 31

By using the material of example 29 (H- [ Ti ] Ti]CHA) and Cu (OAc)₂Ion exchange (2 hours) at 50 ℃ to prepare copper-promoted isomorphously substituted zeolitic materials (Cu- [ Ti)]CHA (SAR 20). The change in Cu concentration during the exchange process produces a series of copper zeolites, such as Cu2.46- [ Ti]CHA (example 31a), Cu3.03- [ Ti]CHA (example 31b), Cu3.64- [ Ti]CHA (example 31c) and Cu3.78- [ Ti]CHA (example 31d) (values after Cu indicate Cu percentage).

Example 32

A standard copper-promoted zeolitic material (cu2.75-CHA) was prepared according to the method provided in u.s.8404203b2 and provided as a reference for the benchmark.

Example 33 comparison

Similar to Cu-CHA, but using Fe (NO) in solution exchange₃)₃Fe-CHA (Fe: 2.5%) was synthesized and selected for comparisonAnd (3) sampling.

Example 34 comparison

Commercial Fe-Beta from BASF was selected as a control sample.

Example 35 comparison

A commercially available Fe-MFI (SCP-306) from Sud-Chemie was selected as a comparison sample.

Example 36

As shown in FIG. 20, in the presence of the framework Ti, not only adsorbed NH₃Increased from 15.2 to 19.1cm in the high temperature region³The desorption temperature was also slightly increased by 10 deg.C (e.g., 470 deg.C to 480 deg.C), indicating that the stronger Lewis acid sites in addition to the acidic protons act as NH₃Store the fractions (example 29v. example 30).

Example 37

As shown in FIG. 21, the increase in Cu percentage only enhances NH in the intermediate temperature zone, e.g., 250 deg.C-400 deg.C, after Cu exchange₃And (4) storing. Integration of the highest desorption peaks for 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 23.8cm respectively³(ii) in terms of/g. Cu- [ Ti ] containing Ti]The CHA sample consistently exhibited two-fold NH above 400 deg.C₃Retention Capacity (example 32v. example 31)

Example 38

However, as shown in FIG. 22, the presence of other lower valence transition metals, such as Fe (III), is not effective in promoting NH above 400 deg.C₃And (4) storing. High temperature of Fe-MFI, Fe-CHA, Fe-Beta: (>The storage capacities at 400 ℃ were 13.6, 12.8 and 7.9cm, respectively³This is a similar level as unmodified Cu-CHA.

Example 39

Cu-CHA (example 32) and Cu3.64- [ Ti]CHA (example 31c) was coated on honeycombs at the same washcoat loading and measured at 5% H at temperature (200 ℃, 300 ℃, 400 ℃, 450 ℃ and 500 ℃)₂NH in the presence of O₃And (4) storing. As shown in FIG. 23, in Cu- [ Ti ] with the help of the skeleton Ti]More chemisorbed NH was consistently found on CHA than on unmodified Cu-CHA₃Up to 400 ℃.

Example 40

Having TiO formed of Ti, Si, Al-based oxides from coprecipitation₂、Al₂O₃And SiO₂Also exhibit high temperature NH₃Storing the feature. As shown in FIG. 24, although the storage capacity of the commercially available material was lower than that of Cu-CHA (example 32), the desorption temperature was further increased.

EXAMPLE 41

Isomorphously substituted zeolite material (Na- [ Ti ] AEI) was prepared in analogy to the material of example 27. The product was recovered by filtration and the template was removed by calcination at 600 ℃ for 5 hours.

Example 42

By NH₄-[Ti]AEI (which passes through NH)₄NO₃(2.4M) with the material of example 41 (Na- [ Ti ] Ti]Double exchange of AEI) at 500 ℃ for 4 hours to prepare an isomorphously substituted zeolitic material (H- [ Ti ] Ti]AEI)。

Example 43

By using the material of example 42 (H- [ Ti ] Ti]AEI) and Cu (OAc)₂(0.06M) preparation of copper-promoted isomorphously substituted zeolitic materials (Cu- [ Ti ] by ion exchange at 50 deg.C (2 hours)]AEI)。

Example 44

Isomorphous substituted zeolite material (Na- [ Ti ] AFX) was prepared similarly to the material of example 27. The product was recovered by filtration and the template was removed by calcination at 600 ℃ for 5 hours.

Example 45

By NH₄-[Ti]AFX (by NH)₄NO₃(2.4M) with the Material of example 44 (Na- [ Ti ]]Double exchange of AFX) at 500 ℃ for the preparation of isomorphously substituted zeolitic materials (H- [ Ti ] Ti]AFX)。

Example 46

By using the material of example 45 (H- [ Ti ] Ti]AFX) and Cu (OAc)₂(0.06M) preparation of copper-promoted isomorphously substituted zeolitic materials (Cu- [ Ti ] by ion exchange at 50 deg.C (2 hours)]AFX)。

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the materials and methods discussed herein (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited 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 and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the materials and methods and does not pose a limitation on the scope thereof 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.

Reference throughout this specification to "one embodiment," "certain embodiments," "one or more embodiments," or "an embodiment" means that a particular element, structure, material, or feature described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the terms "in one or more embodiments," "in certain embodiments," "in one embodiment," or "in an embodiment" in various places throughout this specification are not necessarily referring to the same embodiment of the invention. Furthermore, the particular elements, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

Although the invention herein 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 in the method and apparatus of the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

1. An SCR catalyst comprising a silicon and aluminum atom zeolitic framework material, wherein a portion of the silicon atoms are isomorphously substituted with a tetravalent metal comprising titanium and the catalyst is promoted with a metal selected from the group consisting of Cu, Fe, and combinations thereof, wherein the silicon and aluminum atom zeolitic framework material has an atomic ratio of silica to tetravalent metal in the range of from 1 to 100 and a molar ratio of silica to alumina in the range of from 1 to 300, wherein the zeolitic framework does not include phosphorus atoms, and wherein the zeolitic framework is selected from the group consisting of AEI, CHA, AFX.

2. The catalyst of claim 1 wherein the silica to alumina molar ratio is in the range of 1 to 50.

3. The catalyst of claim 1 having an atomic ratio of tetravalent metal to alumina in the range of 0.0001 to 1000.

4. The catalyst of claim 3 wherein the atomic ratio of tetravalent metal to alumina is in the range of 0.01 to 10.

5. The catalyst of claim 4 wherein the atomic ratio of tetravalent metal to alumina is in the range of 0.01 to 2.

6. The catalyst of claim 1 wherein the atomic ratio of silica to tetravalent metal is in the range of 5 to 20.

7. The catalyst of claim 1, wherein the zeolitic framework material is CHA.

8. The catalyst of claim 1, wherein the catalyst is effective to promote NO⁺Is performed.

9. Selective reduction of Nitrogen Oxides (NO)_x) The method comprising contacting NO_xIs contacted with an SCR catalyst according to any of claims 1 to 8.

10. An exhaust gas treatment system comprising an exhaust gas stream comprising ammonia and an SCR catalyst according to any one of claims 1-8 effective to destroy at least a portion of the ammonia in the exhaust gas stream.

11. An SCR catalyst composite comprising

SCR catalyst according to any of claims 1 to 8, wherein the SCR catalyst selectively promotes the reaction of ammonia with nitrogen oxides to form nitrogen and H in the temperature range of 150 ℃ to 600 ℃₂O; and

an ammonia storage material comprising a transition metal having an oxidation state IV, the ammonia storage material being effective to store ammonia at 400 ℃ and above, having a minimum NH of 0.1g/L at 400 ℃₃And (4) storing quantity.

12. The SCR catalyst composite of claim 11, wherein the transition metal is selected from the group consisting of Ti, Ce, Zr, Hf, Ge, and combinations thereof.

13. The SCR catalyst composite of claim 11, wherein the SCR catalyst is isomorphously substituted with the ammonia storage material.

14. The SCR catalyst composite of claim 11, wherein the ammonia storage material is dispersed in the SCR catalyst.

15. The SCR catalyst composite of claim 11, wherein the ammonia storage material is dispersed as a layer on the SCR catalyst.

16. The SCR catalyst composite of claim 11, wherein the ammonia storage material and the SCR catalyst are arranged in a zoned configuration.

17. The SCR catalyst composite of claim 16, wherein the ammonia storage material is upstream of the SCR catalyst.

18. The SCR catalyst composite of claim 11, wherein the SCR catalyst is ion exchanged with the ammonia storage material.

19. The SCR catalyst composite of claim 11, wherein the SCR catalyst is disposed on a substrate.

20. The SCR catalyst composite of claim 19, wherein the substrate is selected from the group consisting of a wall-flow filter and a flow-through substrate.

21. The SCR catalyst composite of claim 11, wherein the SCR catalyst comprises one or more of a molecular sieve, a mixed oxide, and an activated refractory metal oxide support.

22. The SCR catalyst composite of claim 21, wherein the mixed oxide is selected from the group consisting of Fe/titania, Fe/alumina, Mg/titania, Mg/alumina, Mn/titania, Cu/titania, Ce/Zr, Ti/Zr, vanadia/titania, and mixtures thereof, and wherein the activated refractory metal oxide support is selected from the group consisting of alumina, ceria, zirconia, silica, titania, silica-alumina, zirconia-alumina, titania-alumina, lanthana-zirconia-alumina, baria-lanthana-neodymia-alumina, and mixtures thereof, Alumina-chromia, alumina-ceria, zirconia-silica, titania-silica, or zirconia-titania, and combinations thereof.

23. Simultaneous selective reduction of Nitrogen Oxides (NO)_x) And a method for storing ammonia, the method comprising contacting NO_xIs contacted with an SCR catalyst composite comprising: SCR catalyst according to any of claims 1 to 8, wherein the SCR catalyst selectively promotes the reaction of ammonia with nitrogen oxides to form nitrogen and H in the temperature range of 150 ℃ to 600 ℃₂O; and an ammonia storage material comprising a transition metal having an oxidation state of IV, the ammonia storage material being effective at 400Storing ammonia at temperatures of 400 ℃ and above with a minimum NH of 0.1g/L₃And (4) storing quantity.

24. An SCR catalyst composite comprising

SCR catalyst according to any of claims 1 to 8, wherein the SCR catalyst is effective to selectively promote the reaction of ammonia with nitrogen oxides to form nitrogen and H in the temperature range of 200 ℃ to 600 ℃₂O, wherein the silicon and aluminum atom zeolitic framework material comprises SSZ-13; and

an ammonia storage material comprising Ti, the ammonia storage material being effective to store ammonia at temperatures of 400 ℃ and above.