Cu and Pd co-exchanged zeolites in composites

Abstract

The present invention provides a method for storing and / or reducing nitrogen oxides (NO x ) emissions, catalyst compositions and catalytic articles coated with such compositions, and methods for preparing such catalyst compositions and articles. The catalyst composition comprises a copper and palladium co-exchanged zeolite. Further provided is a method for preparing such a co-exchanged zeolite, an exhaust gas treatment system comprising the catalytic article disclosed herein, and a method for using such a catalytic article and system to reduce NO in an exhaust gas stream x method.

Description

[0001] The present disclosure generally relates to the field of exhaust gas treatment catalysts, and in particular to catalyst compositions capable of selectively reducing nitrogen oxides in engine exhaust, catalyst articles coated with such compositions, and methods for preparing such catalyst compositions. Also provided are catalyst compositions for low temperature capture of nitrogen monoxide (NO) and selective catalytic reduction (SCR) of nitrogen oxides (NO x ) catalyst compositions, and methods for preparing the same.

[0002] Over time, nitrogen oxides (NO x ) cause atmospheric pollution. Exhaust gases from internal combustion engines (e.g., in cars and trucks), from combustion plants (e.g., power plants heated by natural gas, oil, or coal), and from nitric acid production facilities contain NO x .

[0003] Various treatment methods have been used to treat NO x A gas mixture is used to reduce atmospheric pollution. One treatment involves catalytic reduction of nitrogen oxides. There are two methods: (1) a non-selective reduction method, in which carbon monoxide, hydrogen or lower hydrocarbons are used as reducing agents; and (2) a selective reduction method, in which ammonia or an ammonia precursor is used as a reducing agent. In the selective reduction method, a high degree of nitrogen oxide removal can be achieved with a small amount of reducing agent.

[0004] The selective reduction process is known as the SCR (Selective Catalytic Reduction) process. The SCR process catalytically reduces nitrogen oxides with a reducing agent (eg ammonia or an ammonia precursor) in the presence of atmospheric oxygen, resulting in the formation of mainly nitrogen and steam:

[0005] 4NO+4NH3+O2→4N2+6H2O (standard SCR reaction)

[0006] 2NO2+4NH3+O2→3N2+6H2O (slow SCR reaction)

[0007] NO+NO2+2NH3→2N2+3H2O (fast SCR reaction)

[0008] Current catalysts used in the SCR process include molecular sieves, such as zeolites, that are exchanged with catalytic metal ions such as iron or copper. Useful SCR catalyst compositions are able to effectively catalyze NO at temperatures above 200°C and below 600°C. x Reduction of exhaust gas components, enabling reduced NOx even at low load conditions typically associated with lower exhaust temperatures x level.

[0009] Increasingly stringent emission regulations have prompted the need to develop xThe SCR catalyst should have the ability to reduce emissions (such as under lean, low engine exhaust temperature conditions) while also exhibiting sufficient high temperature thermal stability. As emission regulations become increasingly stringent, solving the problem of vehicle cold start NO x Emissions are becoming increasingly important. This represents a challenge because there is no known method to reduce NO x NOx is reduced to N2, which is characteristic of vehicle cold start conditions. NOx traps composed of Pd-exchanged zeolites have recently been developed to capture NOx during cold start and are used in conjunction with SCR products to convert NOx to N2. x The thermal window for emission reduction is extended to lower temperatures. Despite recent advances in SCR and NO capture technologies, there remains a need in the art for catalysts that can effectively reduce NO from the exhaust gas stream under cold start conditions. x emission.

[0010] The present disclosure generally relates to the detection of nitrogen oxides (NO x ) and selective catalytic reduction (SCR) of NO. Surprisingly, it has been discovered in accordance with the present disclosure that base metal ions and Pd ions can be co-exchanged into zeolites with high efficiency and selectivity for ion exchange sites within the zeolite pores. The co-exchanged zeolite catalyst materials so produced exhibit high loadings of ion-exchanged base metals and Pd, as well as NO. x Dual activity of adsorption and reduction. The methods for producing such co-exchanged zeolite catalyst materials, as well as the zeolite catalyst materials themselves, have additional advantages as disclosed herein.

[0011] Thus, in one aspect, there is provided a method for detecting nitrogen oxides (NO x ) is a catalyst composition for low temperature capture and selective catalytic reduction (SCR) of , the catalyst composition comprising a zeolite comprising an ion-exchanged base metal and an ion-exchanged palladium.

[0012] In some embodiments, at least a portion of the ion-exchanged base metal and the ion-exchanged palladium are present in ionic form within the exchange sites of the zeolite.

[0013] In some embodiments, the zeolite has a structure type selected from the group consisting of AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, LTN, MSO, SAS, SAT, SAV, SFW, TSC, and combinations thereof. In some embodiments, the zeolite has a CHA structure type. In some embodiments, the zeolite is an aluminosilicate zeolite having a silica to alumina ratio (SAR) of about 5 to about 100. In some embodiments, the aluminosilicate zeolite has a SAR of about 10 to about 40.

[0014] In some embodiments, the ion-exchange base metal is selected from Cu, Fe, Co, Ni, La, Mn, V, Ag, Ce, Nd, Pr, Ti, Cr, Zn, Nb, Mo, Hf, Y, W, and combinations thereof. In some embodiments, the ion-exchange base metal is Cu, Fe, or a combination thereof. In some embodiments, the ion-exchange base metal is present in the zeolite in an amount of about 0.01% to about 15% by weight, calculated as base metal oxide, based on the total weight of the calcined ion-exchange zeolite free of volatiles. In some embodiments, the ion-exchange base metal is Cu. In some embodiments, Cu is present in the zeolite in an amount of about 0.1% to about 4% by weight, calculated as CuO, based on the total weight of the calcined ion-exchange zeolite free of volatiles.

[0015] In some embodiments, the ion-exchanged palladium, calculated as elemental palladium, is present in the zeolite in an amount of about 0.01% to about 4% by weight, based on the total weight of the volatile-free calcined ion-exchanged zeolite.

[0016] In another aspect, there is provided a method for x A catalyst article for low temperature capture and SCR of the present invention comprises: a substrate; and a first washcoat comprising a catalyst composition according to the present disclosure disposed on at least a portion of the substrate.

[0017] In some embodiments, the substrate is honeycomb. In some embodiments, the honeycomb substrate is a wall flow filter substrate or a flow-through substrate.

[0018] In some embodiments, the catalyst article is effective for adsorbing nitric oxide (NO) at a temperature of about 20°C to about 200°C.

[0019] In some embodiments, the catalyst article is effective to reduce NO and NO at temperatures above about 200°C. x .

[0020] In some embodiments, the catalyst article further comprises a second washcoat disposed on at least a portion of the substrate, the second washcoat comprising an SCR catalyst composition. In some embodiments, the first and second washcoats are present in a zoned configuration. In some embodiments, the second washcoat is disposed downstream of the first washcoat.

[0021] In some embodiments, based on the NO present in the exhaust gas stream x The catalyst product effectively reduces NO in the exhaust gas stream under cold start conditions. xEmissions are reduced by at least about 10%, at least about 15%, at least about 25%, at least about 35%, at least about 45%, at least about 55%, at least about 65%, at least about 75%, at least about 85%, or at least about 95% by weight, wherein cold start conditions include an exhaust gas flow temperature of less than about 150°C.

[0022] In another aspect, an exhaust treatment system for treating an exhaust gas flow from a lean burn engine is provided, the exhaust treatment system comprising a catalytic article according to the present disclosure in fluid communication with the exhaust gas flow. In some embodiments, the exhaust treatment system further comprises one or more additional components selected from the group consisting of a diesel oxidation catalyst (DOC), a soot filter, a selective catalytic reduction (SCR) catalyst, a urea injection component, an ammonia oxidation catalyst (AMOx), a lean NO x Traps (LNT) and combinations thereof. In some embodiments, the lean burn engine is a diesel engine.

[0023] In yet another aspect, a method for reducing NO in an exhaust gas stream of a lean burn engine is provided. x A method for treating an exhaust gas stream in contact with a catalytic article or an exhaust gas treatment system according to the present disclosure, based on the NO present in the exhaust gas stream. x The total amount, time and temperature are sufficient to remove NO from the exhaust gas stream. x The level is reduced by at least about 10%, at least about 15%, at least about 25%, at least about 35%, at least about 45%, at least about 55%, at least about 65%, at least about 75%, at least about 85% or at least about 95% by weight.

[0024] In yet another aspect, a method for preparing a zeolite co-exchanged with both base metal ions and palladium ions is provided, the method comprising contacting a zeolite comprising base metal ions with a source of palladium ions in an aqueous medium such that the palladium ions are ion-exchanged into the zeolite comprising the base metal ions, thereby forming a zeolite co-exchanged with both base metal ions and palladium ions.

[0025] In some embodiments, the method further comprises drying the zeolite co-exchanged with both the base metal ions and the palladium ions; and calcining the zeolite co-exchanged with both the base metal ions and the palladium ions.

[0026] In some embodiments, the palladium ion source is [Pd(NH3)4][OH]2. In some embodiments, the ion-exchange base metal is Cu, Fe, or a combination thereof. In some embodiments, at least a portion of the ion-exchange base metal and the ion-exchange palladium are present in the exchange sites of the zeolite in ionic form.

[0027] In some embodiments, the zeolite has a structure type selected from the group consisting of AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, LTN, MSO, SAS, SAT, SAV, SFW, TSC, and combinations thereof. In some embodiments, the zeolite has a CHA structure type. In some embodiments, the zeolite is an aluminosilicate zeolite having a silica to alumina ratio (SAR) of about 5 to about 100. In some embodiments, the aluminosilicate zeolite has a SAR of about 10 to about 40.

[0028] In some embodiments, the ion-exchanged base metal is present in the zeolite at an initial concentration; after contacting the zeolite comprising base metal ions with a source of palladium ions in an aqueous medium, the ion-exchanged base metal is present in the zeolite at a final concentration; and the final concentration is within about 10% of the initial concentration.

[0029] In some embodiments, the ion-exchanged palladium, calculated as elemental palladium, is present in the zeolite in an amount of about 0.01% to about 4% by weight, based on the total weight of the volatile-free calcined ion-exchanged zeolite.

[0030] In some embodiments, the ion exchange base metal is Cu, and Cu calculated as CuO is present in the zeolite in an amount of about 0.1% to about 4% by weight based on the total weight of the calcined ion exchange zeolite free of volatiles. In some embodiments, ion exchange palladium calculated as elemental palladium is present in the zeolite in an amount of about 0.1% to about 4% by weight based on the total weight of the calcined ion exchange zeolite free of volatiles. In some embodiments, at least about 50% of the Cu and at least about 50% of the palladium are present in ion exchange sites in the pore network of the zeolite.

[0031] In order to provide an understanding of the embodiments of the present disclosure, reference is made to the accompanying drawings, in which the figure numerals refer to components of exemplary embodiments of the present disclosure. The accompanying drawings are exemplary only and should not be construed as limiting the present disclosure. The disclosure described herein is shown in the accompanying drawings by way of example and not limitation. For simplicity and clarity of illustration, the features illustrated in the drawings do not have to be drawn to scale. For example, for clarity, the size of some features may be enlarged relative to other features. Further, where deemed appropriate, reference numerals have been repeated in the accompanying drawings to indicate corresponding or similar elements.

[0032] Figure 1A is a perspective view of a honeycomb-type substrate that may include a catalyst composition according to the present disclosure (i.e., in the form of a washcoat);

[0033] Figure 1B is relative to Figure 1A Zoom in and follow the Figure 1AA partial cross-sectional view taken through a plane of an end face of a substrate, showing an embodiment in which the substrate is a flow-through substrate, Figure 1A an enlarged view of the plurality of airflow channels shown;

[0034] Figure 2 is relative to Figure 1A A cross-sectional view of an enlarged portion of the Figure 1A The honeycomb-type substrate in represents a wall-flow filter;

[0035] Figure 3A is a cross-sectional view of an embodiment of a catalyst article of the present disclosure having a layered configuration;

[0036] Figure 3B is a cross-sectional view of an embodiment of a catalyst article of the present disclosure having a zoned configuration;

[0037] Figure 3C is a cross-sectional view of an embodiment of a catalyst article of the present disclosure having a layered and zoned configuration (i.e., having overlapping layers);

[0038] Figure 3D is a cross-sectional view of an embodiment of a catalyst article of the present disclosure having another layered and zoned configuration;

[0039] Figure 3E is a cross-sectional view of an embodiment of a catalyst article of the present disclosure having yet another layered and zoned configuration;

[0040] Figure 4 is used for NO x Schematic diagram of an embodiment of the emission treatment system of the present disclosure with a low temperature capture and SCR catalyst article;

[0041] Figure 5A is a schematic diagram of one embodiment of an emission treatment system of the present disclosure, the emission treatment system comprising a NOx disposed on a substrate in a first zone as described herein. x Adsorbent / SCR catalyst composition; and an SCR catalyst composition disposed on the same substrate in a second zone downstream of the first zone to form a single NO x Adsorbent / SCR / SCR catalyst products; among which NO x The adsorbent / SCR / SCR catalyst article is located downstream of and in fluid communication with the lean-burn engine; and

[0042] Figure 5B is a schematic diagram of one embodiment of an emission treatment system of the present disclosure, the system comprising a first substrate disposed on a first substrate to form a combined NO x Adsorbent / SCR catalyst articles as described herein for NO xAdsorbent / SCR catalyst composition; and an SCR catalyst article disposed on a second substrate, wherein NO x The adsorbent / SCR catalyst article is located downstream of and in fluid communication with the lean burn engine, and the SCR catalyst article is located in the combined NO x Downstream of the adsorbent / SCR article and with the combined NO x The adsorbent / SCR article is in fluid communication.

[0043] The present disclosure provides a method for low temperature capture and selective catalytic reduction (SCR) of nitrogen oxides (NOx) from the exhaust gas stream of a lean burn engine. x ) catalyst composition. Further provided are methods of preparing the disclosed SCR catalyst composition, as well as catalyst articles, exhaust gas treatment systems, and methods of treating exhaust gas streams, each of which comprises the disclosed SCR catalyst composition.

[0044] Surprisingly, as disclosed herein, it has been discovered that zeolite materials comprising palladium (Pd) ions and base metal ions, both ion types being co-exchanged into the zeolite pore network, can be efficiently prepared by near quantitative uptake of Pd ions. Such zeolites are capable of being used as both NO capture agents and SCR catalysts, and have additional advantageous properties.

[0045] Before describing several exemplary embodiments of the present disclosure, it should be understood that the present disclosure is not limited to the details of construction or process steps set forth in the following description. The present disclosure is capable of other embodiments and can be practiced or carried out in various ways.

[0046] The articles "a" and "an" refer to one (kind) or more than one (kind) (e.g., at least one (kind)) of the grammatical object in this article. Any range listed herein includes end values. The term "about" used throughout the text is used to describe and explain small fluctuations. For example, "about" can mean that the numerical value can be modified by ±5%, ±4%, ±3%, ±2%, ±1%, ±0.5%, ±0.4%, ±0.3%, ±0.2%, ±0.1% or ±0.05%. Whether or not it is explicitly stated, all numerical values ​​are modified by the term "about". The numerical values ​​modified by the term "about" include specific identification values. For example, "about 5.0" includes 5.0. Unless otherwise specified herein, the reference to the numerical range herein is intended only to be used as a shorthand method for referring to each individual value falling within the range, respectively, and each individual value is incorporated into this specification as if it were individually cited herein.

[0047] “AMO x ” refers to a selective ammonia oxidation catalyst, which is a catalyst comprising one or more metals (typically Pt, but not limited thereto) and an SCR catalyst capable of converting ammonia into nitrogen.

[0048] As used herein, "base metal" refers to a compound containing a transition metal or lanthanide element (e.g., vanadium (V), tungsten (W), titanium (Ti), copper (Cu), iron (Fe), cobalt (Co), nickel (Ni), chromium (Cr), manganese (Mn), cerium (Ce), lanthanum (La), praseodymium (Pr), zinc (Zn), niobium (Nb), zirconium (Zr), molybdenum (Mo), tin (Sn), silver (Ag), gold (Au), or a combination thereof) that has an effect on NO x The reduction of NO is catalytically active, or promotes the reduction of another catalytic component to NO x Base metals include copper, iron, manganese, tin, cobalt, nickel and combinations thereof. For ease of reference, the concentrations of base metals are reported in the form of metal oxides.

[0049] As used herein, the term "BET surface area" has its ordinary meaning and refers to the Brunauer, Emmett, Teller method for determining surface area by N2 adsorption. Pore size and pore volume can also be determined using BET-type N2 adsorption or desorption experiments.

[0050] The term "catalyst" refers to a material that promotes a chemical reaction. Catalytically active substances are also called "promoters" because they accelerate a chemical reaction.

[0051] The term "catalytic article" or "catalyst article" refers to a component used to promote a desired reaction. The catalytic article of the present invention comprises a "substrate" having disposed thereon at least one catalytic coating.

[0052] "CSF" refers to a catalyzed soot filter, which is a wall-flow monolith. A wall-flow filter comprises alternating inlet and outlet channels, wherein the inlet channels are plugged at the outlet end and the outlet channels are plugged at the inlet end. The soot-laden exhaust gas flow entering the inlet channels is forced through the filter walls before the outlet channels. In addition to soot filtration and regeneration, the CSF may also carry an oxidation catalyst to oxidize CO and HC to CO2 and H2O, or to oxidize NO to NO2 to accelerate downstream SCR catalysis or promote oxidation of soot particles at lower temperatures. When located after the LNT catalyst, the CSF may have an H2S oxidation function to suppress H2S emissions during the LNT desulfurization process.

[0053] "DOC" refers to a diesel oxidation catalyst, which converts hydrocarbons and carbon monoxide in diesel exhaust. Typically, a DOC comprises one or more platinum group metals, such as palladium and / or platinum; a support material, such as alumina; a zeolite for HC storage; and optionally a promoter and / or stabilizer.

[0054] Typically, the term "effective" means, for example, about 35% to 100% effective, for example, about 40%, about 45%, about 50% or about 55% to about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90% or about 95% effective by weight or mole relative to the defined catalytic activity or storage / release activity.

[0055] The term "exhaust stream" or "exhaust gas stream" refers to any combination of flowing gases that may contain solid or liquid particulate matter. A stream contains a gaseous component, and is for example the exhaust gas of a lean burn engine, which may contain certain non-gaseous components, such as liquid droplets, solid particles, etc. The exhaust stream of an internal combustion engine typically further contains combustion products (CO2 and H2O), incomplete combustion products (carbon monoxide (CO) and hydrocarbons (HC)), nitrogen oxides (NO x ), combustibles and / or carbonaceous particulate matter (soot) and unreacted oxygen and nitrogen.

[0056] "GDI" refers to a gasoline direct injection engine that operates under lean-burn conditions.

[0057] A "high surface area refractory metal oxide support" specifically refers to a support having a surface area greater than High surface area refractory metal oxide supports (e.g., alumina support materials), also known as "gamma alumina" or "activated alumina," typically exhibit fresh material BET surface areas in excess of 60 square meters per gram ("m 2 / g”), usually up to about 200m 2 This type of activated alumina is usually a mixture of γ and δ phases of alumina, but may also contain significant amounts of η, κ and θ alumina phases.

[0058] As used herein, "impregnated" or "impregnation" refers to the penetration of the catalytic material into the porous structure of the support material.

[0059] The term "fluidly connected" is used to refer to articles that are located on the same exhaust line, i.e., a common exhaust gas flow passes through the articles that are fluidly connected to each other. The articles that are fluidly connected may be adjacent to each other in the exhaust line. Alternatively, the articles that are fluidly connected may be separated by one or more articles, also referred to as "carrier-coated monoliths".

[0060] "LNT" means lean NO x The trapping agent is a catalyst comprising a platinum group metal (e.g., Pt and Rh), ceria and a catalyst suitable for adsorbing NO under lean combustion conditions. x Under oxygen-rich conditions, NO x is released and reduced to nitrogen.

[0061] "LT-NA" means low temperature NO x The adsorbent is a composition containing, for example, a palladium-exchanged zeolite. Under cold start conditions, NO x is adsorbed and then released as the temperature of the exhaust gas stream increases.

[0062] As used herein, the phrase "molecular sieve" refers to framework materials, such as zeolites and other framework materials (e.g., isomorphously substituted materials), which may be in particulate form and used as a catalyst in combination with one or more promoter metals. Molecular sieves are materials based on an extensive three-dimensional network of oxygen ions that generally contain tetrahedral sites and have a substantially uniform pore distribution, the average pore size of which is no greater than 100 microns.

[0063] Molecular sieves can be distinguished primarily on the basis of the geometry of the interstices formed by the rigid network of (SiO4) / AlO4 tetrahedra. The entrance to the atomic interstices is formed by 6, 8, 10 or 12 ring atoms relative to the atoms forming the entrance opening. Zeolites are crystalline materials with fairly uniform pore sizes, which, depending on the type of molecular sieve and the type and number of cations included in the molecular sieve lattice, range from about 3 to 100 microns in diameter. The phrase "8-ring" molecular sieve refers to a molecular sieve having 8 ring pore openings and double six-ring secondary structural units and having a cage-like structure generated by connecting double six-ring structural units through 4 rings. Molecular sieves include small pore, medium pore and large pore molecular sieves or combinations thereof. The pore size is defined by the ring size.

[0064] The term “NO x ” refers to nitrogen oxide compounds such as NO, NO2 or N2O.

[0065] The terms "on" and "over" with respect to coatings may be used synonymously. The term "directly on" means in direct contact. In certain embodiments, the disclosed articles are referred to as comprising one coating "on" a second coating, and such language is intended to encompass embodiments with intervening layers where direct contact between coatings is not required (i.e., "on" is not equivalent to "directly on").

[0066] "Platinum group metal (PGM)" refers to any PGM (Ru, Rh, Os, Ir, Pd, Pt and / or Au). Reference to "PGM" allows the PGM to exist in any valence state. For example, the PGM can be in the form of a zero-valent metal, or the PGM can be in the form of an oxide. The terms "platinum (Pt) component", "rhodium (Rh) component", "palladium (Pd) component", "iridium (Ir) component", "ruthenium (Ru) component", etc. refer to the respective platinum group metal compounds, complexes, etc., which decompose or convert into a catalytically active form, typically a metal or metal oxide, when calcined or used as a catalyst.

[0067] As used herein, the term "promoted" refers to components that are added to, for example, a zeolite material, typically by ion exchange, as opposed to impurities inherent in the zeolite. Zeolites can be promoted, for example, with copper (Cu) and / or iron (Fe), although other catalytic metals such as manganese, cobalt, nickel, cerium, platinum, palladium, rhodium, or combinations thereof can be used.

[0068] The term "promoter metal" refers to one or more metals added to an ion-exchanged zeolite to produce a modified "metal-promoted" molecular sieve. Promoter metals are added to ion-exchanged zeolites to increase the catalytic activity of the active metal present at the exchange sites in the zeolite compared to ion-exchanged zeolites without promoter metals, for example, aluminum or alumina is added as a "promoter metal" to a copper ion-exchanged zeolite to enhance the catalytic activity of copper by preventing and / or reducing the formation of catalytically less active copper oxide clusters.

[0069] As used herein, the term "selective catalytic reduction" (SCR) refers to a catalytic process that reduces nitrogen oxides to dinitrogen (N2) using a nitrogen-containing reductant. SCR catalyst compositions typically contain a zeolite promoted with a metal such as copper, iron, or a combination thereof.

[0070] "SCRoF" (ie, SCR on filter) refers to an SCR catalyst composition coated directly on a wall flow filter.

[0071] "Substantially free" means "little or no" or "not intentionally added", and also only trace and / or unintentional amounts. For example, in certain embodiments, "substantially free" means less than about 2 wt.% (weight %), less than about 1.5 wt.%, less than about 1.0 wt.%, less than about 0.5 wt.%, less than about 0.25 wt.%, or less than about 0.01 wt.%, based on the weight of the indicated total composition.

[0072] As used herein, the term "substrate" refers to a monolithic material on which a catalyst composition (i.e., a catalytic coating) is disposed, typically in the form of a washcoat. In one or more embodiments, the substrate is a flow-through monolith and a monolithic wall-flow filter. Reference to a "monolithic substrate" refers to a monolithic structure that is uniform and continuous from inlet to outlet.

[0073] As used herein, the term "support" or "support material" refers to any material, such as a high specific surface area material, typically a refractory metal oxide material, to which a metal (e.g., PGM, stabilizer, promoter, binder, etc.) is applied by precipitation, association, dispersion, impregnation or other suitable method. Exemplary supports include porous refractory metal oxide supports as described below. The term "support" means "dispersed on," "incorporated into," "impregnated into," "on," "in," "deposited on," or otherwise associated with.

[0074] As used herein, the terms "upstream" and "downstream" refer to the relative directions of flow according to the engine exhaust gas flow from the engine to the tail pipe, wherein the engine is located in an upstream position and the tail pipe and any pollutant reduction products such as filters and catalysts are located downstream of the engine. The inlet end of the substrate is synonymous with the "upstream" end or "front" end. The outlet end is synonymous with the "downstream" end or "rear" end. The upstream zone is upstream of the downstream zone. The upstream zone can be closer to the engine or manifold, while the downstream zone can be farther away from the engine or manifold.

[0075] "Washcoat" has its ordinary meaning in the art, i.e., a thin, adherent coating of a material (e.g., a catalyst) applied to a "substrate," such as a honeycomb flow-through monolith substrate or filter substrate that is sufficiently porous to allow the treated gas stream to pass therethrough. As used herein and as described in Heck, Ronald and Farrauto, Robert, Catalytic Air Pollution Control (New York: Wiley-Interscience, 2002), pp. 18-19, washcoat layers include a compositionally different layer of material disposed on a monolithic substrate surface or underlying washcoat layer. Washcoats are formed by preparing a slurry of the catalyst containing a specific solids content (e.g., about 30% to about 90% by weight) in a liquid, then applying the slurry to a substrate and drying to provide a washcoat layer. A substrate may contain one or more washcoat layers, and each washcoat layer may differ in some manner (e.g., may differ in its physical properties, such as particle size or microcrystalline phase) and / or may differ in chemical catalytic function.

[0076] As used herein, the term "zeolite" refers to a specific example of a molecular sieve including silicon atoms and aluminum atoms. Typically, zeolite is defined as an aluminosilicate with an open 3-dimensional framework structure composed of corner-sharing TO4 tetrahedrons, wherein T is Al or Si, or optionally P. Zeolite can include SiO4 / AlO4 tetrahedrons connected by common oxygen atoms to form a three-dimensional network. The cations that balance the charge of the anion framework are loosely associated with the framework oxygen, and the remaining pore volume is filled with water molecules. Non-framework cations are usually exchangeable, and water molecules are removable. The aluminosilicate zeolite structure does not include phosphorus or other metals that are isomorphously substituted in the framework. That is, "aluminosilicate zeolite" does not include aluminophosphate materials (such as SAPO, AlPO and MeAlPO materials), and the more general term "zeolite" includes aluminosilicates and aluminophosphates. For the purposes of this disclosure, SAPO, AlPO and MeAlPO materials are considered to be non-zeolitic molecular sieves.

[0077] Zeolites are microporous solids containing pores and channels of various sizes. The cations that balance the charge of the anionic framework are loosely associated with the framework oxygen, and the remaining pore volume is filled with water molecules. Non-framework cations are generally exchangeable, and water molecules are removable. A variety of cations can occupy these pores and can move through these channels. As used herein, the term "intrapore site" refers to a site available for cations within the zeolite pore structure. Intrapore sites refer to all internal spaces within the zeolite pore structure that can be occupied by cations, such as exchange sites and / or defect sites. "Exchange sites" refer to sites available for cations, which are mainly occupied by ion-exchanged metal cations (such as Cu and Pd), which are added to zeolites to adsorb NO x substances and / or to promote chemical reactions.

[0078] Unless otherwise indicated, all parts and percentages are by weight. If not otherwise indicated, "weight percent (wt %)" is based on the entire composition without any volatiles, ie, based on dry solids content.

[0079] Unless otherwise indicated herein or otherwise clearly contradicted by context, all methods described herein can be performed in any suitable order. The use of any and all examples or exemplary language (e.g., "such as") provided herein is intended only to better illustrate the materials and methods, and does not limit the scope unless otherwise claimed. The language in this specification should not be interpreted as indicating that any unclaimed element is necessary for the practice of the disclosed materials and methods.

[0080] All U.S. patent applications, published patent applications, and patents cited herein are hereby incorporated by reference.

[0081] The present invention provides a method for removing nitrogen oxides (NO x ) is a catalyst composition for low temperature capture and selective catalytic reduction (SCR) of NO, the catalyst composition comprising a zeolite comprising an ion-exchanged base metal and an ion-exchanged palladium. Such a catalyst composition is referred to herein as NO x Adsorbent / SCR Catalyst Compositions. The individual components of the catalyst composition are further described below.

[0082] As used herein, the term zeolite refers to a specific example of a molecular sieve, including silicon atoms and aluminum atoms. According to one or more embodiments, the zeolite can be based on a framework topology by which the structure is identified. In some embodiments, any structural type of zeolite can be used, such as ABW, ACO, AEI, AEL, AEN, AET, AFG, AFI, AFN, AFO, AFR, AFS, AFT, AFX, AFY, AHT, ANA, APC, APD, AST, ASV, ATN, ATO, ATS, ATT, ATV, AWO, AWW, BCT, BEA, BEC, BIK, BOG, BPH, BRE, CAN, CAS, SCO ,CFI,SGF,CGS,CHA,CHI,CLO,CON,CZP,DAC,DDR,DFO,DFT,DOH,DON,EAB,EDI,EMT,EON,EPI,ERI,ESV,ET R, EUO, FAU, FER, FRA, GIS, GIU, GME, GON, GOO, HEU, IFR, IHW, ISV, ITE, ITH, ITW, IWR, IWW, JBW, KFI, LAU, LE V, LIO, LIT, LOS, LOV, LTA, LTL, LTN, MAR, MAZ, MEI, MEL, MEP, MER, MFI, MFS, MON, MOR, MOZ, MSO, MTF, MTN, M TT, MTW, MWW, NAB, NAT, NES, NON, NPO, NSI, OBW, OFF, OSI, OSO, OWE, PAR, PAU, PHI, PON, RHO, RON, RRO, RSN, R Structural type of TE, 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 a combination thereof.

[0083] Zeolites may be further characterized by reference to their pore size, as mentioned herein with respect to molecular sieves.The zeolites of the present invention may be small pore, medium pore or large pore zeolites and combinations thereof.

[0084] Small pore zeolites contain channels defined by up to eight tetrahedral atoms. As used herein, the term "small pore" refers to a pore size of less than about (Angstroms), e.g. about Examples of small pore zeolites include framework types ACO, AEI, AEN, AFN, AFT, AFX, ANA, APC, APD, ATT, CDO, CHA, DDR, DFT, EAB, EDI, EPI, ERI, GIS, GOO, IHW, ITE, ITW, LEV, KFI, MER, MON, NSI, OWE, PAU, PHI, RHO, RTH, SAT, SAV, SIV, THO, TSC, UEI, UFI, VNI, YUG, ZON, and mixtures or intergrowths thereof.

[0085] Medium pore zeolites contain channels defined by ten-membered rings. Examples of medium pore zeolites include framework types AEL, AFO, AHT, BOF, BOZ, CGF, CGS, CHI, DAC, EUO, FER, HEU, IMF, ITH, ITR, JRY, JSR, JST, LAU, LOV, MEL, MFI, MFS, MRE, MTT, MVY, MWW, NAB, NAT, NES, OBW, PAR, PCR, PON, PUN, RRO, RSN, SFF, SFG, STF, STI, STT, STW, SVR, SZR, TER, TON, TUN, UOS, VSV, WEI, WEN, and mixtures or intergrowths thereof.

[0086] Large pore zeolites contain channels defined by twelve-membered rings. Examples of large pore zeolites include framework types AFI, AFR, AFS, AFY, ASV, ATO, ATS, BEA, BEC, BOG, BPH, BSV, CAN, CON, CZP, DFO, EMT, EON, EZT, FAU, GME, GON, IFR, ISV, ITG, IWR, IWS, IWV, IWW, JSR, LTF, LTL, MAZ, MEI, MOR, MOZ, MSE, MTW, NPO, OFF, OKO, OSI, RON, RWY, SAF, SAO, SBE, SBS, SBT, SEW, SFE, SFO, SFS, SFV, SOF, SOS, STO, SSF, SSY, USI, UWY, VET, and mixtures or intergrowths thereof.

[0087] In some embodiments, the zeolite has a structure type selected from the group consisting of AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, LTN, MSO, SAS, SAT, SAV, SFW, TSC, and combinations thereof. In some embodiments, the zeolite has a framework type CHA. In some embodiments, the zeolite is SSZ-13.

[0088] The molar ratio of silica to alumina ("SAR") of the zeolites of the present invention can vary widely, but is generally 2 or greater. For example, the zeolites of the present invention can have a SAR of about 5 to about 1000. In some embodiments, the zeolite has a molar ratio of silica to alumina (SAR) in the range of about 2 to about 300, such as about 5 to about 250, about 5 to about 200, about 5 to about 100, or about 5 to about 50. In some embodiments, the zeolite has a SAR in the range of about 10 to about 200, such as about 10 to about 100, about 10 to about 75, about 10 to about 60, or about 10 to about 50. In some embodiments, the zeolite has a SAR in the range of about 15 to about 100, such as about 15 to about 75, about 15 to about 60, or about 15 to about 50. In some embodiments, the zeolite has a SAR in the range of about 20 to about 100, such as about 20 to about 75, about 20 to about 60, or about 20 to about 50. In some embodiments, the molar ratio of Si to Al in the framework, calculated as a molar ratio of SiO2:Al2O3, is from about 2 to 100. In some embodiments, the molar ratio of Si to Al is from about 5 to about 100. In some embodiments, the molar ratio of Si to Al is from about 10 to about 40. In some embodiments, the molar ratio of Si to Al is about 25.

[0089] The zeolites of the present invention may exhibit a high surface area, for example a BET surface area of ​​at least about 200 m 2 / g, at least about 400m 2 / g, at least about 500m 2 / g, or at least about 1000m 2 / g, or at least about 1400m 2 / g, for example, about 200 to about 1500 m 2 / g, or about 500 to about 750m 2 / g. "BET surface area" has its usual meaning: it refers to the Brunauer, Emmett, Taylor method for determining surface area by N2 adsorption. In some embodiments, the BET surface area is from about 550 to about 700 m 2 / g.

[0090] As disclosed herein, NO xThe adsorbent / SCR catalyst composition comprises a zeolite comprising an ion exchange base metal and an ion exchange palladium. In some embodiments, the ion exchange base metal is selected from Cu, Fe, Co, Ni, La, Mn, V, Ag, Ce, Nd, Pr, Ti, Cr, Zn, Nb, Mo, Hf, Y, W, and combinations thereof. In some embodiments, the ion exchange base metal is Cu, Fe, or a combination thereof. In certain embodiments, the base metal is Cu.

[0091] The amount of ion exchange base metal present in the zeolite can vary. In some embodiments, based on the total weight of the calcined zeolite without volatiles, the ion exchange base metal calculated as base metal oxide is present in an amount of about 0.1 to about 20% by weight. In some embodiments, based on the total weight of the calcined zeolite, the ion exchange base metal is present in an amount of about 0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about 0.7, about 0.8, about 0.9 or about 1 to about 2, about 5, about 10, about 15, or about 20% by weight. In some embodiments, the ion exchange base metal is Cu, and based on the total weight of the calcined zeolite, Cu calculated as CuO is present in the zeolite in an amount of about 0.1% to about 4% by weight, for example, based on the total weight of the calcined zeolite without volatiles, about 1% to about 4%, about 2% to about 4%, about 2% to about 3%, or about 3% to about 4% by weight.

[0092] As disclosed herein, NO x The adsorbent / SCR catalyst composition comprises a zeolite comprising an ion-exchange base metal and an ion-exchange palladium. In some embodiments, the ion-exchange palladium calculated as elemental palladium is present in an amount of about 0.01% to about 20% by weight, based on the total weight of the calcined zeolite free of volatiles. In some embodiments, the ion-exchange palladium is present in an amount of about 0.01, about 0.02, about 0.03, about 0.04, about 0.05, about 0.06, about 0.07, about 0.08, about 0.09, or about 0.1 to about 0.5, about 1, about 2, about 5, about 10, or about 20% by weight, based on the total weight of the calcined zeolite free of volatiles. In some embodiments, the ion-exchanged palladium, calculated as elemental palladium, is present in an amount of 0.01% to about 4% by weight, based on the total weight of the calcined zeolite, e.g., about 1% to about 4%, about 2% to about 4%, or about 3% to about 4% by weight, based on the total weight of the calcined zeolite free of volatiles.

[0093] In some embodiments, at least a portion of ion exchange base metals and ion exchange palladium is present in the exchange site of zeolite in ionic form. A portion of ion exchange base metals and / or ion exchange palladium may be present outside the exchange site, for example, as particles of corresponding base metals or palladium or its oxide, arranged on the surface of zeolite. The co-ion exchange zeolite of the present invention is different from, for example, a physical mixture of a zeolite exchanged with base metal ions and a zeolite exchanged with palladium ions. The presence of Pd and base metal ions in the ion exchange site of zeolite can be determined by, for example, X-ray diffraction (XRD) studies. Extracting unit cell parameters from XRD can be used to indicate the ion distribution in the zeolite material.

[0094] It is believed that the presence of both base metal ions and palladium ions in the same zeolite exchange site may be advantageous. Without wishing to be bound by theory, it is believed that the physical proximity of the base metal ions and palladium ions results in NO being captured by the palladium ions under cold start conditions. x The material is more efficiently transferred to the catalytically active base metal ions, such as when the catalyst composition is heated to the operating temperature. Thus, non-productive desorption of, for example, NO can be minimized. In addition, higher loadings of base metal ions and palladium ions can be achieved by co-exchange, resulting in a more effective catalyst. Finally, in some embodiments, a single catalytic article comprising a substrate coated with a catalytic composition according to the present disclosure can function as a catalyst for NO removal. x Adsorption and NO x The combined action of SCR can potentially eliminate the need for conventional NO x In other embodiments, the combined N x The adsorption and SCR characteristics significantly enhance the NO in gaseous exhaust streams using conventional downstream SCR catalyst products. x of emission reductions.

[0095] On the other hand, a method for preparing a zeolite co-exchanged with both base metal ions and palladium ions disclosed herein is provided. The method comprises contacting a zeolite comprising base metal ions with a source of palladium ions in an aqueous medium so that the palladium ions are ion-exchanged into the zeolite comprising the base metal ions, thereby forming a zeolite co-exchanged with both base metal ions and palladium ions. In some embodiments, the base metal is Cu. In some embodiments, the base metal is Fe.

[0096] Various base metal promoted zeolites and methods for their preparation are well known. Typically, base metals (e.g., copper, iron, etc.) are ion exchanged into zeolites. Such base metals are typically ion exchanged into alkali metal or NH4 zeolites (which can be prepared by methods known in the art, such as the method disclosed by Bleken, F. et al. in Topics in Catalysis, 2009, 52, 218-228, which is incorporated herein by reference), by ion exchange of NH4 into alkali metal zeolites.

[0097] In addition to low temperature adsorption of NO x In addition to substances, in order to further promote the SCR of nitrogen oxides, in some embodiments, two or more metals (e.g., a combination of copper and one or more other metals) can be used to promote zeolites that are co-exchanged with both base metal ions and palladium ions. In some embodiments, the base metal is a combination of Cu and Fe. In the case where two or more base metals are included in the metal-promoted zeolite material, multiple metal precursors (e.g., copper and iron precursors) can be ion-exchanged simultaneously or separately. In certain embodiments, the second metal can be exchanged into a zeolite material that is first promoted with a first metal (e.g., a second metal can be ion-exchanged into a zeolite material promoted by iron or copper).

[0098] In some embodiments, starting with such a base metal ion exchange zeolite, a source of palladium ions in an aqueous medium is contacted with the base metal ion exchange zeolite. In some embodiments, the source of palladium ions is [Pd(NH3)4][OH]2. Without wishing to be bound by theory, it is believed that the reaction of hydroxide anions with protons present in the zeolite ion exchange sites provides the driving force for the reaction according to Equation 1:

[0099] [Pd(NH3)4][OH]2+2HZ→PdZ2+4NH3+2H2O(1)

[0100] The methods disclosed herein are superior to typical ion exchange methods involving "inert" counterions such as nitrates, where the extent of Pd uptake will be affected by the amount of Pd(OH2)6 in solution. 2+ and Pd in ​​zeolite 2+ The equilibrium established between the two is affected, resulting in incomplete and reproducible absorption. The method disclosed herein has the further advantage that the near quantitative or quantitative absorption of palladium ions avoids the need for large amounts of Pd recovery.

[0101] In some embodiments, at least a portion of the ion-exchanged base metal and ion-exchanged palladium are present in ionic form within the exchange sites of the zeolite. As described herein, this is different from zeolites containing base metals and palladium, wherein the majority of the base metal and palladium are in non-ionic form (e.g., as metal or oxide thereof, in the form of clusters, and / or otherwise outside of the ion exchange sites within the pores of the zeolite).

[0102] Methods as disclosed herein have further advantages, namely that the absorption of palladium ions does not substantially displace existing base metal ions (e.g., Cu). In some embodiments, the ion-exchanged base metal is present in the zeolite at an initial concentration. After contacting the zeolite containing base metal ions with a source of palladium ions in an aqueous medium, the ion-exchanged base metal is present in the zeolite at a final concentration. In some embodiments, the final concentration is within about 10% of the initial concentration. For example, the final concentration of base metal ions (e.g., Cu) is about 10%, about 9%, about 8%, about 7%, about 6%, about 5%, about 4%, about 3%, about 2%, about 1%, or even less than about 1% of the initial concentration.

[0103] In some embodiments, the methods disclosed herein provide a co-exchanged zeolite wherein the ion-exchanged palladium, calculated as elemental palladium, is present in the zeolite in an amount of about 0.01% to about 4% by weight, based on the total weight of the volatile-free calcined ion-exchanged zeolite.

[0104] In some embodiments, the method disclosed herein provides a co-exchanged zeolite, wherein the ion exchange base metal is Cu, and based on the total weight of the calcined ion exchange zeolite free of volatiles, Cu calculated as CuO is present in the zeolite in an amount of about 0.1% to about 4% by weight. In some embodiments, based on the total weight of the calcined ion exchange zeolite free of volatiles, the ion exchange palladium calculated as elemental palladium is present in the zeolite in an amount of about 0.1% to about 4% by weight, and at least about 50% of Cu and at least about 50% of palladium are present in the ion exchange sites in the pore network of the zeolite. For example, about 50%, about 60%, about 70%, about 80%, about 90%, about 95%, about 99% or even about 100% of Cu, palladium or both are present in the ion exchange sites in the pore network of the zeolite.

[0105] As described herein, any suitable zeolite can be used for the method. In some embodiments, the zeolite has a structure type selected from the group consisting of AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, LTN, MSO, SAS, SAT, SAV, SFW, TSC, and combinations thereof. In some embodiments, the zeolite has a CHA structure type. In some embodiments, the zeolite is an aluminosilicate zeolite with a silicon dioxide to alumina ratio (SAR) of about 5 to about 100. In some embodiments, the aluminosilicate zeolite has a SAR of about 10 to about 40.

[0106] In some embodiments, the method further comprises drying the zeolite co-exchanged with both the base metal ions and the palladium ions, and calcining the zeolite co-exchanged with both the base metal ions and the palladium ions.

[0107] In another aspect, there is provided a method for x A catalyst article for low temperature capture and SCR of the present invention, the catalyst article comprising a substrate and a first washcoat, the first washcoat comprising a NO according to the present disclosure disposed on at least a portion of the substrate x Adsorbent / SCR catalyst composition.

[0108] In one or more embodiments, for NO x The present invention of low temperature capture and SCR of NO x The adsorbent / SCR catalyst composition is disposed on one or more substrates to form a catalyst article. Catalytic articles comprising a substrate are typically used as part of an exhaust gas treatment system (e.g., catalyst articles, including but not limited to, NO x Articles of adsorbent / SCR catalyst composition). Useful substrates are 3-dimensional, having a length, diameter, and volume similar to a cylinder. The shape does not have to conform to a cylinder. The length is the axial length defined by the inlet and outlet ends.

[0109] According to one or more embodiments, the substrate for the disclosed catalyst can be composed of any material commonly used to prepare automotive catalysts, and will generally comprise a metal or ceramic honeycomb structure. The substrate generally provides a plurality of wall surfaces on which a washcoat composition is applied and adhered, thereby serving as a substrate for the catalyst.

[0110] The ceramic substrate can be made of any suitable refractory material, such as cordierite, cordierite-α-alumina, aluminum titanate, silicon titanate, silicon carbide, silicon nitride, zircon mullite, spodumene, alumina-silica-magnesia, zirconium silicate, sillimanite, magnesium silicate, zircon, petalite, α-alumina, aluminosilicates, the like, and combinations thereof.

[0111] The substrate may also be metallic, comprising one or more metals or metal alloys. The metal substrate may include any metal substrate, such as those with openings or "punchings" in the channel wall. The metal substrate may take various shapes, such as particles, compressed metal fibers, corrugated plates, or integral foams. Specific examples of metal substrates include heat-resistant base metal alloys, especially those alloys in which iron is a basic or main component. Such alloys may contain one or more of nickel, chromium, and aluminum, and the total amount of these metals may advantageously include at least about 15 wt.% (weight percent) of the alloy, for example, about 10 to about 25 wt.% of chromium, about 1 to about 8 wt.% of aluminum, and about 0 to about 20 wt.% of nickel, in each case based on the weight of the substrate. Examples of metal substrates include substrates with straight channels; substrates with protruding blades along axial channels to interrupt gas flow and open channels for gas flow communication; and substrates with blades and holes to enhance gas transmission between channels and thereby allow radial gas transmission throughout the monolith.

[0112] Any suitable substrate for the catalytic articles disclosed herein may be employed, such as a monolithic substrate having thin parallel gas flow channels extending through the substrate from an inlet face or an outlet face of the substrate such that the channels are open to a fluid flowing through the substrate (a "flow-through substrate"). Another suitable substrate is a type having a plurality of thin substantially parallel gas flow channels extending along the longitudinal axis of the substrate, wherein typically each channel is blocked at one end of the substrate body, with alternating channels being blocked at the opposite end face (a "wall-flow filter"). Flow-through and wall-flow substrates are also taught, for example, in International Application Publication No. WO2016 / 070090, which is incorporated herein by reference in its entirety.

[0113] In some embodiments, the catalyst substrate comprises a honeycomb substrate in the form of a wall flow filter or a flow-through substrate. In some embodiments, the substrate is a wall flow filter. In some embodiments, the substrate is a flow-through substrate. Flow-through substrates and wall flow filters are discussed further below.

[0114] In some embodiments, the substrate is a flow-through substrate (e.g., a monolithic substrate, including a flow-through honeycomb monolithic substrate). The flow-through substrate has thin parallel gas flow channels extending from the inlet end of the substrate to the outlet end, so that the channels are open to fluid flow. These channels are essentially straight paths from their fluid inlet to their fluid outlet, defined by walls on or in which a catalytic coating is disposed, so that the gas flowing through the channels contacts the catalytic material. The flow channels of the flow-through substrate are thin-walled channels, which can be any suitable cross-sectional shape and size, such as trapezoidal, rectangular, square, sinusoidal, hexagonal, elliptical, circular, etc. As described above, the flow-through substrate can be ceramic or metallic.

[0115] The flow-through substrate may, for example, have a 3 About 1200in 3 volume, a cell density (entrance opening) of about 60 cells per square inch (cpsi) to about 500 cpsi or up to about 900 cpsi, for example, a cell density of about 200 to about 400 cpsi and a wall thickness of about 50 to about 200 microns or about 400 microns.

[0116] In some embodiments, the substrate is a wall-flow filter, which typically has a plurality of thin, substantially parallel airflow channels extending along the longitudinal axis of the substrate. Typically, each channel is blocked at one end of the substrate body, and alternating channels are blocked at the opposite end face. Such integral wall-flow filter substrates may contain up to about 900 or more flow channels (or "cells") per square inch of cross-section, although far fewer flow channels may be used. For example, the substrate may have about 7 to about 600, more typically about 100 to about 400 cells per square inch ("cpsi"). The cells may have a cross-section of a rectangular, square, circular, elliptical, triangular, hexagonal, or other polygonal shape. As described above, the wall-flow filter substrate may be ceramic or metallic.

[0117] Figure 1A and Figure 1B An exemplary substrate 2 is shown in the form of a flow-through substrate coated with a catalyst composition described herein. Figure 1A , the exemplary substrate 2 has a cylindrical shape and a cylindrical outer surface 4, an upstream end face 6, and a downstream end face 8 corresponding to the same end face 6. The substrate 2 has a plurality of thin, parallel gas flow channels 10 formed therein. Figure 1B As shown, the flow channel 10 is formed by the wall 12 and extends through the carrier 2 from the upstream end face 6 to the downstream end face 8, and the channel 10 is unobstructed, thereby allowing a fluid, such as an airflow, to flow longitudinally through the carrier 2 via its airflow channel 10. Figure 1B As can be more easily seen in the figure, the wall 12 is sized and configured so that the gas flow channel 10 has a substantially regular polygonal shape. As shown, if desired, the catalyst composition can be applied in multiple different layers. In the embodiment shown, the catalyst composition includes both a discrete bottom layer 14 adhered to the wall 12 of the support member and a second discrete top layer 16 coated on the bottom layer 14. The present disclosure can be practiced with one or more (e.g., two, three, or four or more) catalyst composition layers and is not limited to Figure 1B Two layer embodiment shown. Additional coating configurations are disclosed herein below.

[0118] Figure 2A cross-sectional view of a portion of a monolithic wall-flow filter substrate is shown, showing alternating blocked and open channels (cells). Blocked or plugged ends 100 alternate with open channels 101, with each opposite end open and blocked, respectively. The filter has an inlet end 102 and an outlet end 103. Arrows through the porous cell walls 104 represent the flow of exhaust gas entering the open cell end, diffusing through the porous cell walls 104, and exiting the open outlet cell end. The plugged ends 100 prevent gas flow and promote diffusion through the cell walls. Each cell wall will have an inlet side 104a and an outlet side 104b. The channels are surrounded by cell walls.

[0119] The wall flow filter article substrate may have a volume of, for example, about 50 in. 3 、About 100in 3 、About 200in 3 、About 300in 3 、About 400in 3 、About 500in 3 、About 600in 3 、About 700in 3 、About 800in 3 、About 900in 3 or about 1000in 3 To about 1500in 3 、About 2000in 3 、About 2500in 3 、About 3000in 3 、About 3500in 3 、About 4000in 3 、About 4500in 3 or about 5000in 3 The wall flow filter substrate typically has a wall thickness of about 50 microns to about 2000 microns, such as about 50 microns to about 450 microns or about 150 microns to about 400 microns.

[0120] The walls of the wall-flow filter are porous and typically have a wall porosity of at least about 40% or at least about 50% and an average pore size of at least about 10 microns before the functional coating is set. For example, in some embodiments, the wall-flow filter article substrate will have a porosity of ≥40%, ≥50%, ≥60%, ≥65% or ≥70%. For example, before the catalytic coating is set, the wall-flow filter article substrate will have a wall porosity of about 50%, about 60%, about 65% or about 70% to about 75%, and an average pore size of about 10 or about 20 to about 30 or about 40 microns. The terms "wall porosity" and "substrate porosity" mean the same thing and are interchangeable. Porosity is the ratio of the void volume (or pore volume) divided by the total volume of the substrate. Pore size and pore size distribution are typically determined by Hg porosimetry measurements.

[0121] The SCR catalytic coating of the present invention may include one or more coatings, at least one of which contains the NO x Adsorbent / SCR catalyst composition. The catalytic coating may include one or more thin adherent coatings disposed on and adhered to at least a portion of the substrate. The entire coating comprises a single "coat".

[0122] In order to prepare the NO x Adsorbent / SCR catalyst articles, using the NO x The adsorbent / SCR catalyst composition coats the substrates described herein. The coating is a "catalytic coating composition" or a "catalytic coating." "Catalyst composition" and "catalytic coating composition" are synonyms.

[0123] Typically, a catalyst composition is prepared and coated on a substrate. The method may include applying a NO x The adsorbent / SCR catalyst composition is mixed with a solvent (eg, water) to form a slurry that is used to coat the catalyst substrate.

[0124] As disclosed herein, NO x The adsorbent / SCR catalyst composition slurry may further comprise additional components, such as a binder and / or a refractory metal oxide. An exemplary binder is a ZrO2 binder derived from a suitable precursor such as zirconyl nitrate or any other suitable zirconium precursor such as zirconyl nitrate. Zirconyl acetate binders provide a coating that remains uniform and intact after thermal aging, such as when the catalyst is exposed to a high temperature of at least about 600°C, such as about 800°C and higher and a high water vapor environment of about 5% or more. Other potentially suitable binders include, but are not limited to, alumina and silica. Alumina binders include alumina, aluminum hydroxide, and aluminum hydroxide. Colloidal forms of aluminum salts and alumina may also be used. Silica binders include various forms of SiO2, including silicates and colloidal silica. The binder composition may include any combination of zirconium oxide, alumina, and silica.

[0125] Other exemplary binders include boehmite, gamma-alumina or delta / theta alumina, and silica sol. When present, the binder is typically used in an amount of about 1-5 wt % of the total washcoat loading. Alternatively, the binder can be zirconia-based or silica-based, such as zirconium acetate, zirconia sol, or silica sol. When present, alumina binders are typically used in an amount of about 0.05 g / in 3 About 1g / in 3 The amount used.

[0126] The slurry may optionally contain various additional components. Common additional components include, but are not limited to, binders as described above, additives that control, for example, the pH and viscosity of the slurry. Additional components may include hydrocarbon (HC) storage components (e.g., zeolites), associative thickeners and / or surfactants (including anionic, cationic, nonionic or amphoteric surfactants). The usual pH range of the slurry is from about 3 to about 6. Acidic or alkaline substances may be added to the slurry to adjust the pH accordingly. For example, in some embodiments, the pH of the slurry is adjusted by adding aqueous acetic acid.

[0127] The solid content of the slurry comprising metal ion exchanged zeolite particles can vary depending on the intended use. In some embodiments, the solid content of the slurry is from about 15 to about 45 wt % based on the weight of the mixture.

[0128] The slurry can be ground to a reduced particle size and to enhance mixing of the particles and formation of a homogenous material. The grinding can be done in a ball mill, a continuous mill or other similar equipment, and the solids content of the slurry can be, for example, about 20 to about 60 wt % or about 20 to about 40 wt %. In one embodiment, the slurry after grinding is characterized by D 90 The particle size is from about 1 to about 40 microns, from about 2 to about 20 microns, or from about 4 to about 15 microns.

[0129] The NO of the present invention x The adsorbent / SCR catalyst composition may be prepared with a NO x The adsorbent / SCR catalyst composition is applied in the form of one or more washcoats. The washcoat is prepared by preparing a slurry of the catalyst composition (or one or more components of the catalyst composition) containing a specific solids content (e.g., about 10 to about 60% by weight) in a liquid vehicle, which is then applied to the substrate using any washcoat technique known in the art, and dried and calcined to provide a coating. If multiple coatings are applied, the substrate is dried and / or calcined after each washcoat is applied and / or after the desired number of washcoats have been applied.

[0130] After calcination, the catalyst loading obtained by the above washcoat technique can be determined by calculating the difference between the coated and uncoated weights of the substrate. It will be apparent to one skilled in the art that the catalyst loading can be varied by changing the slurry rheology. In addition, the coating / drying / calcining process to produce the washcoat layer (coating) can be repeated as needed to structure the coating to the desired loading level or thickness, meaning that more than one washcoat can be applied.

[0131] The catalytic coating of the present invention may comprise one or more coatings, at least one of which comprises the catalyst composition of the present invention or one or more components of the catalyst composition. The catalytic coating may comprise one or more thin adhesion coatings disposed on and adhered to at least a portion of the substrate. The entire coating comprises a single "coating".

[0132] In some embodiments, the catalytic articles of the present invention may include the use of one or more catalyst layers and combinations of one or more catalyst layers. The catalytic material may be present only on the inlet side of the substrate wall, only on the outlet side, on both the inlet side and the outlet side, or the wall itself may consist entirely or partially of the catalytic material. The catalytic coating may be on the surface of the substrate wall and / or in the pores of the substrate wall, i.e., in the substrate wall and / or on the substrate wall. Thus, the phrase "carrier coating disposed on a substrate" refers to any surface, such as on the wall surface and / or on the pore surface.

[0133] One or more washcoats may be applied so that the different coating layers are in direct contact with the substrate. Alternatively, there may be one or more "undercoats" so that at least a portion of the catalytic coating layer or layers is not in direct contact with the substrate (but is in contact with the undercoat). There may also be one or more "overcoats" so that at least a portion of the one or more coating layers is not directly exposed to the gas stream or atmosphere (but is in contact with the overcoat).

[0134] Alternatively, the NO of the present invention x The adsorbent / SCR catalyst composition may be in a top coat layer over a bottom coat layer. x The adsorbent / SCR catalyst composition may be present in a top layer and a bottom layer. Any one layer may extend the entire axial length of the substrate, for example, the bottom layer may extend the entire axial length of the substrate, and the top layer may also extend the entire axial length of the substrate above the bottom layer. Each of the top layer and the bottom layer may extend from the inlet end or the outlet end.

[0135] For example, both the primer and the topcoat can extend from the same substrate end, wherein the top layer partially or completely covers the bottom layer, and wherein the bottom layer extends the partial or full length of the substrate, and wherein the top layer extends the partial or full length of the substrate. Alternatively, the top layer can cover a part of the bottom layer. For example, the bottom layer can extend the entire length of the substrate, and the top layer can extend about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80% or about 90% of the substrate length from the inlet end or the outlet end.

[0136] Alternatively, the bottom layer may extend about 10%, about 15%, about 25%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 95% of the length of the substrate from the inlet or outlet end, and the top layer may extend about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, or about 95% of the length of the substrate from the inlet or outlet end, wherein at least a portion of the top layer covers the bottom layer. This "coverage" zone may, for example, extend from about 5% to about 80% of the length of the substrate, such as about 5%, about 10%, about 20%, about 30%, about 40%, about 50%, about 60% or about 70% of the length of the substrate.

[0137] In some embodiments, a NO as disclosed herein disposed on a substrate as disclosed herein x The adsorbent / SCR catalyst composition comprises a first washcoat, wherein the first washcoat is disposed over at least a portion of the length of the catalyst substrate; and a second washcoat comprising an additional SCR catalyst composition, wherein the second washcoat is disposed over at least a portion of the length of the catalyst substrate. Any suitable SCR catalyst composition may be used; such SCR compositions are known in the art.

[0138] In some embodiments, the first washcoat is disposed directly on the catalyst substrate, and the second washcoat is disposed on at least a portion of the first washcoat. In some embodiments, the second washcoat is disposed directly on the catalyst substrate, and the first washcoat is disposed on at least a portion of the second washcoat. In some embodiments, the first washcoat is disposed directly on the catalyst substrate from the inlet end to a length of about 10% to about 50% of the total length; and the second washcoat is disposed on at least a portion of the first washcoat. In some embodiments, the second washcoat is disposed directly on the catalyst substrate from the inlet end to a length of about 50% to about 100% of the total length; and the first washcoat is disposed on at least a portion of the second washcoat. In some embodiments, the first washcoat is disposed directly on the catalyst substrate from the inlet end to a length of about 20% to about 40% of the total length, and the second washcoat extends from the inlet end to the outlet end. In some embodiments, the first washcoat is disposed directly on the catalyst substrate from the outlet end to a length of about 10% to about 50% of the total length, and the second washcoat is disposed on at least a portion of the first washcoat. In some embodiments, the first washcoat is disposed directly on the catalyst substrate from the outlet end to a length of about 20 to about 40% of the total length, and the second washcoat extends from the inlet end to the outlet end. In some embodiments, the second washcoat is disposed directly on the catalyst substrate from the outlet end to a length of about 50% to about 100% of the total length, and the first washcoat is disposed on at least a portion of the second washcoat. In some embodiments, the first washcoat is disposed directly on the catalyst substrate, covering about 100% of the total length, and the second washcoat is disposed on the first washcoat, covering about 100% of the total length. In some embodiments, the second washcoat is disposed directly on the catalyst substrate, covering about 100% of the total length, and the first washcoat is disposed on the second washcoat, covering about 100% of the total length.

[0139] The catalytic coating can be advantageously "partitioned", comprising a catalytic layer of partitions, i.e., wherein the catalytic coating contains a composition that varies on the axial length of the substrate. This can also be described as "lateral partitioning". For example, a layer can extend from the inlet end to the outlet end, and extend about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80% or about 90% of the length of the substrate. Another layer can extend from the outlet end to the inlet end, and extend about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80% or about 90% of the length of the substrate. Different coatings can be adjacent to each other and do not cover each other. Alternatively, different layers can cover a portion of each other, thereby providing a third "middle" zone. The intermediate zone may, for example, extend from about 5% to about 80% of the length of the substrate, such as about 5%, about 10%, about 20%, about 30%, about 40%, about 50%, about 60% or about 70% of the length of the substrate.

[0140] The zones of the present disclosure are defined by the relationship of the coatings. There are many possible zone configurations for different coatings. For example, there can be an upstream zone and a downstream zone, there can be an upstream zone, an intermediate zone, and a downstream zone, there can be four different zones, etc. In the case where the two layers are adjacent and do not overlap, there are upstream zones and downstream zones. In the case where the two layers overlap to a certain extent, there are upstream zones, downstream zones, and intermediate zones. For example, in the case where the coatings extend the entire length of the substrate and the different coatings extend a certain length from the outlet end and cover a portion of the first coating, there are upstream zones and downstream zones.

[0141] For example, NO of the present invention x The adsorbent / SCR catalyst article may include an upstream zone comprising an NO x A first washcoat of an adsorbent / SCR catalyst composition; and a downstream zone comprising a second washcoat containing an SCR catalyst composition as described herein. Alternatively, the upstream zone may comprise a second washcoat layer and the downstream zone may comprise a first washcoat layer.

[0142] In some embodiments, the first washcoat is disposed on the catalyst substrate from the inlet end to a length of about 10% to about 50% of the total length; and the second washcoat is disposed on the catalyst substrate from the outlet end to a length of about 50% to about 90% of the total length. In some embodiments, the first washcoat is disposed on the catalyst substrate from the inlet end to a length of about 10% to about 50% of the total length; and the second washcoat is disposed on the catalyst substrate from the inlet end to a length of about 50% to about 90% of the total length.

[0143] Figure 3A , Figure 3B , Figure 3C, Figure 3D and Figure 3E An example coating configuration with two coatings is shown. Shown is a substrate wall 200 with coatings 201 (top coating) and 202 (bottom coating) disposed thereon. This is a simplified illustration, in the case of a porous wall flow substrate, the pores and coatings adhered to the pore walls are not shown, and the plugged ends are not shown. Figure 3A , coatings 201 and 202 each extend the entire length of the substrate, with the top layer 201 covering the bottom layer 202. Figure 3A The substrate does not contain a partition coating configuration. Figure 3B A zoned configuration is shown with coating 202 extending about 50% of the length of the substrate from the outlet to form a downstream zone 204 and coating 201 extending about 50% of the length of the substrate from the inlet to provide an upstream zone 203. Figure 3C In the embodiment of the present invention, the bottom coating 202 extends about 50% of the length of the substrate from the outlet, and the top coating 201 extends more than 50% of the length from the inlet and covers a portion of the layer 202, thereby providing an upstream region 203, an intermediate coverage region 205, and a downstream region 204. Figure 3D In the embodiment, the bottom coating 202 extends about 100% of the length of the substrate from the inlet, and the top coating 201 extends more than 50% of the length from the inlet and covers a portion of the layer 202, thereby providing an upstream region 203 and a downstream region 204. Figure 3E In FIG. 2 , the bottom coating 201 extends about 100% of the length of the substrate from the inlet, and the top coating 202 extends more than 50% of the length from the outlet and covers a portion of the layer 201 , thereby providing an upstream zone 203 and a downstream zone 204 . FIG. 3A to FIG. 3E Can be used to illustrate coating compositions on wall-flow substrates or flow-through substrates.

[0144] As disclosed herein, the NO x The adsorbent / SCR catalyst article effectively adsorbs NO in the presence of a reductant (e.g., ammonia or an ammonia precursor). x components and catalyzes NO from lean-burn engine exhaust x The article of the present invention effectively adsorbs and / or catalyzes NO at various temperatures. x In some embodiments, the NO x The adsorbent / SCR catalyst article is effective for adsorbing nitric oxide (NO) at a temperature of about 20°C to about 200°C, for example, from about 20°C, about 30°C, about 40°C, about 50°C, about 60°C, about 70°C, about 80°C, about 90°C, or about 100°C to about 150°C, about 175°C, or about 200°C. In some embodiments, the NO adsorbent / SCR catalyst article according to the present disclosure is effective for adsorbing nitric oxide (NO) at a temperature of about 20°C to about 200°C, for example, from about 20°C, about 30°C, about 40°C, about 50°C, about 60°C, about 70°C, about 80°C, about 90°C, or about 100°C to xThe adsorbent / SCR catalyst article is effective for reducing NO at a temperature above about 200°C, such as from about 200°C, about 250°C, about 300°C, or about 350°C to about 400°C, about 450°C, about 500°C, about 550°C, or about 600°C. x .

[0145] In some embodiments, NO according to the present disclosure x Adsorbent / SCR catalyst products effectively remove NO from the exhaust gas stream under cold start conditions x Emissions are reduced by at least about 10%, at least about 15%, at least about 25%, at least about 35%, at least about 45%, at least about 55%, at least about 65%, at least about 75%, at least about 85%, or at least about 95% by weight, wherein cold start conditions include an exhaust gas flow temperature of less than about 150°C, e.g., from about 20°C to about 150°C.

[0146] In another aspect, an exhaust gas treatment system for treating an exhaust gas flow from a lean burn engine is provided, the exhaust gas treatment system comprising a NOx according to the present disclosure in fluid communication with the exhaust gas flow. x Adsorbent / SCR catalyst article. The engine may be, for example, a diesel engine operating under combustion conditions where the air exceeds that required for stoichiometric combustion, i.e., lean burn conditions. In other embodiments, the engine may be a lean burn gasoline engine or an engine associated with a stationary source (e.g., a generator or pump station).

[0147] Exhaust treatment systems typically contain more than one catalytic article located downstream of the engine in fluid communication with the exhaust gas flow. The system may contain, for example, a selective catalytic reduction catalyst (SCR), a diesel oxidation catalyst (DOC), and a reductant injector, a soot filter, an ammonia oxidation catalyst (AMOx), or a lean NOx catalyst. x The exhaust gas treatment system of the present invention may further include a soot filter and / or an ammonia oxidation catalyst. The soot filter may be uncatalyzed or may be catalyzed (CSF). For example, in some embodiments, the exhaust gas treatment system according to the present disclosure may include, in addition to the NO x In addition to adsorbent / SCR catalyst products, it can also include DOC, CSF, urea injectors, SCR products, products containing AMOx, lean NO x Capture agents (LNT) and combinations thereof.

[0148] The relative positions of the various catalytic components present within the exhaust treatment system may vary. In the exhaust treatment systems and methods of the present invention, the exhaust gas flow is contained to one or more articles or treatment systems by entering an upstream end and exiting a downstream end. The inlet end of a substrate or article is synonymous with the "upstream" end or "front" end. The outlet end is synonymous with the "downstream" end or "rear" end. The treatment system is typically located downstream of an internal combustion engine and in fluid communication with the internal combustion engine.

[0149] Figure 4 An exemplary exhaust treatment system is shown in FIG. 2 , which depicts a schematic diagram of an exhaust treatment system 20. As shown, the exhaust treatment system may include a plurality of catalyst components connected in series downstream of an engine 22 (e.g., a lean-burn diesel or gasoline engine). At least one catalyst component is a NO x Adsorbent / SCR catalyst products. NO x The adsorbent / SCR catalyst composition may be combined with a number of additional catalyst materials and may be placed in various locations relative to the additional catalyst materials. Figure 4 Five catalyst components 24, 26, 28, 30, 32 are shown in series; however, the total number of catalyst components may vary, and five components are merely an example. Those skilled in the art will recognize that it may be desirable to arrange the relative positions of each article in an order different from that shown herein; the present disclosure contemplates such alternative orderings.

[0150] Without intending to be limiting, Table 1 presents various example exhaust treatment system configurations according to one or more embodiments of the present disclosure. Note that each catalyst is connected to the next catalyst via an exhaust conduit such that the engine is upstream of catalyst A, catalyst A is upstream of catalyst B, catalyst B is upstream of catalyst C, catalyst C is upstream of catalyst D, and catalyst D is upstream of catalyst E (when present). References to components AE in Table 1 may be the same as Figure 4 Cross-references with the same name in .

[0151] "DOC" in Table 1 is meant to refer to a diesel oxidation catalyst as defined above. The DOC component may comprise any suitable DOC catalyst composition.

[0152] "CSF" in Table 1 refers to a catalyzed soot filter as defined above. The CSF component may comprise any suitable oxidation catalyst composition.

[0153] "LNT" in Table 1 refers to lean NOx as defined above. x Traps. The LNT component may comprise any suitable LNT catalyst composition.

[0154] "SCR" in Table 1 refers to a selective catalytic reduction catalyst as defined above. The SCR component may comprise any suitable SCR catalyst composition.

[0155] "SCRoF" in Table 1 refers to a selective catalytic reduction catalyst coated on a wall flow filter as defined above. The SCRoF component may comprise any suitable SCR catalyst composition.

[0156] "AMOx" in Table 1 refers to a selective ammonia oxidation catalyst as defined above. The AMOx component may comprise any suitable AMOx catalyst composition. In some embodiments, the AMOx catalyst may be provided downstream of the other components to remove any leaked ammonia from the exhaust treatment system. In some embodiments, the optional AMOx component may be an independent catalyst article comprising an AMOx catalyst composition coated on a substrate separate from the other components and located downstream and in fluid communication with the other components. In other embodiments, in an exemplary exhaust treatment system according to Table 1, the optional AMOx component may comprise an AMOx catalyst composition coated on a portion of the component immediately upstream of the optional AMOx component (e.g., an outlet zone). For example, referring to Configuration 1 in Table 1, in some embodiments, components B and C may comprise separate catalyst articles, wherein component B comprises an SCR catalyst composition coated on a first substrate and component C comprises an AMOx catalyst composition coated on a second substrate located downstream and in fluid communication with the first substrate. In other embodiments of Configuration 1, components B and C may comprise a single catalyst article comprising an SCR catalyst composition and an AMOx catalyst composition coated on a single substrate in a zoned configuration (eg, including an SCR upstream zone and an AMOx downstream zone).

[0157] The “NO x / SCR" refers to NO x Adsorbent / SCR catalyst. NO x The SCR component may contain any NO according to the present disclosure. x Adsorbent / SCR catalyst composition. In some embodiments, NO x The SCR component is a stand-alone catalyst article containing NO coated on a substrate separate from other components in the exhaust gas treatment system. x Adsorbent / SCR catalyst composition. In some embodiments, NO x The SCR component may include NO coated on a flow-through substrate. x Adsorbent / SCR catalyst composition. In some embodiments, NO x The SCR component may include NO coated on a wall flow filter substrate.x Adsorbent / SCR catalyst composition.

[0158] "NO in Table 1 x / SCR / SCR" refers to a single catalyst article comprising NO x The adsorbent / SCR catalyst and the SCR catalyst as defined above. For example, in some embodiments, NO x / SCR / The SCR component may include a NO according to the present disclosure disposed on a substrate in the first zone. x The adsorbent / SCR catalyst composition and the SCR catalyst composition on the same substrate disposed in a second zone downstream of the first zone to form a Figure 5A The depicted single NO x Adsorbent / SCR / SCR Catalyst Articles. In some embodiments, the substrate is a flow-through substrate.

[0159] "NO in Table 1 x / SCR / SCRoF" refers to NO x A single catalyst article of an adsorbent / SCR catalyst and a SCRoF catalyst as defined above. For example, in some embodiments, NO x The / SCR / SCRoF component may include a NO according to the present disclosure disposed on a wall flow filter substrate in the first zone. x Adsorbent / SCR catalyst composition, and an SCR catalyst composition on the same wall flow filter substrate disposed in a second zone downstream of the first zone to form a single NO x Adsorbent / SCR / SCRoF catalyst products.

[0160] As will be appreciated by those skilled in the art, in the configurations listed in Table 1, any one or more of components A, B, C, D, or E may be disposed on a particulate filter (e.g., a wall-flow filter, or a flow-through honeycomb substrate). In some embodiments, the engine exhaust treatment system includes one or more catalyst compositions mounted near the engine (at a close coupled position, CC) and an additional catalyst composition mounted at a position below the vehicle body (i.e., at an under-floor (UF) position). In some embodiments, the exhaust treatment system may further include a urea injection component.

[0161] Table 1. Possible exhaust gas treatment system configurations

[0162]

[0163]

[0164] It is further contemplated herein that certain catalytic functions may be combined in a single article or may be provided as separate articles. x The adsorbent / SCR catalyst may be combined with a conventional SCR catalyst on a single substrate, or on a separate substrate within a single article. Figure 5A and Figure 5B As disclosed herein, NO x Two non-limiting configurations of adsorbent / SCR catalysts combined with conventional SCR catalysts.

[0165] refer to Figure 5A , as described herein NO x The adsorbent / SCR catalyst composition is disposed on a substrate in a first zone; and the SCR catalyst composition is disposed on the same substrate in a second zone downstream of the first zone to form a single NO x Adsorbent / SCR / SCR catalyst products. NO x The adsorber / SCR / SCR catalyst article is located downstream of and in fluid communication with the lean burn engine.

[0166] refer to Figure 5B , as described herein NO x The adsorbent / SCR catalyst composition is disposed on a first substrate to form NO x Adsorbent / SCR catalyst article. A conventional SCR catalyst article is disposed on a second substrate, wherein NO x The adsorbent / SCR catalyst article is located downstream of and in fluid communication with the lean burn engine, whereas a conventional SCR catalyst article is located in a combined NO x Downstream of the adsorbent / SCR combination and with NO x The adsorbent / SCR composition is in fluid communication.

[0167] In another aspect of the present disclosure, a method for reducing NO in an exhaust gas flow of a lean-burn engine is provided. x In general, the method comprises contacting the exhaust gas stream with a catalytic article of the present disclosure or an emission treatment system of the present disclosure. More particularly, the method comprises contacting the exhaust gas stream with a NO x The adsorbent / SCR catalyst article, or an exhaust gas treatment system as disclosed herein, is contacted with the exhaust gas treatment system for a time and temperature sufficient to reduce NO in the exhaust gas stream. x Level. NO x The degree of reduction in levels may vary. In some embodiments, based on the NO present in the exhaust gas stream, xThe total amount of the agent is reduced by at least about 10%, at least about 15%, at least about 25%, at least about 35%, at least about 45%, at least about 55%, at least about 65%, at least about 75%, at least about 85% or at least about 95% by weight.

[0168] NO x Adsorbent / SCR catalyst products effectively adsorb nitric oxide (NO) and / or reduce NO and NO x The temperature range can vary. For example, in some embodiments, NO x The adsorbent / SCR catalyst article is effective for adsorbing NO at a temperature of about 20°C to about 200°C, such as from about 20°C, about 30°C, about 40°C, about 50°C, about 60°C, about 70°C, about 80°C, about 90°C, or about 100°C to about 150°C, about 175°C, or about 200°C. In some embodiments, NO x The adsorbent / SCR catalyst article effectively adsorbs NO at a temperature above about 200°C, such as from about 200°C, about 250°C, about 300°C, or about 350°C to about 400°C, about 450°C, about 500°C, about 550°C, or about 600°C. x .

[0169] The method may include treating NO as disclosed herein x The adsorbent / SCR catalyst article is positioned downstream of the engine and the engine exhaust stream is directed through the catalyst article. In one or more embodiments, the method further comprises positioning an additional catalyst component downstream of the engine as described above.

[0170] The catalyst compositions, articles, systems and methods of the present invention are suitable for treating exhaust streams from internal combustion engines, such as gasoline, light diesel engines and heavy diesel engines. The catalyst compositions are also suitable for treating emissions from stationary industrial processes, removing harmful or toxic substances from indoor air, or for catalysis in chemical reaction processes.

[0171] It will be apparent to those of ordinary skill in the relevant art that appropriate modifications and changes may be made to the compositions, methods and applications described herein without departing from the scope of any embodiment or aspect thereof. The compositions and methods provided are exemplary and are not intended to limit the scope of the claimed embodiments. All various embodiments, aspects and options disclosed herein may be combined in all variations. The scope of the compositions, formulations, methods and processes described herein includes all actual or potential combinations of the embodiments, aspects, options, examples and preferences herein. All patents and publications cited herein are incorporated herein by reference for their specific teachings as mentioned, unless other specific incorporation statements are specifically provided.

[0172] Without limitation, some embodiments of the present disclosure include:

[0173] 1. A method for treating nitrogen oxides (NO x ) is a catalyst composition for low temperature capture and selective catalytic reduction (SCR) of , the catalyst composition comprising a zeolite comprising an ion-exchanged base metal and an ion-exchanged palladium.

[0174] 2. The catalyst composition of embodiment 1, wherein at least a portion of the ion-exchange base metal and the ion-exchange palladium are present in ionic form within the exchange sites of the zeolite.

[0175] 3. The catalyst composition according to embodiment 1 or 2, wherein the zeolite has a structure type selected from the group consisting of AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, LTN, MSO, SAS, SAT, SAV, SFW, TSC, and combinations thereof.

[0176] 4. The catalyst composition according to any one of embodiments 1 to 3, wherein the zeolite has a CHA structure type.

[0177] 5. The catalyst composition of any one of claims 1 to 4, wherein the zeolite is an aluminosilicate zeolite having a silica to alumina ratio (SAR) of about 5 to about 100.

[0178] 6. The catalyst composition of claim 5, wherein the aluminosilicate zeolite has a SAR of about 10 to about 40.

[0179] 7. The catalyst composition of any one of embodiments 1 to 6, wherein the ion-exchange base metal is selected from Cu, Fe, Co, Ni, La, Mn, V, Ag, Ce, Nd, Pr, Ti, Cr, Zn, Nb, Mo, Hf, Y, W, and combinations thereof.

[0180] 8. The catalyst composition of any one of embodiments 1 to 7, wherein the ion-exchanged base metal is Cu, Fe, or a combination thereof.

[0181] 9. The catalyst composition of any one of embodiments 1 to 8, wherein the ion-exchanged base metal, calculated as the base metal oxide, is present in the zeolite in an amount of about 0.01% to about 15.0% by weight, based on the total weight of the calcined ion-exchanged zeolite free of volatiles.

[0182] 10. The catalyst composition of embodiment 9, wherein the ion-exchange base metal is Cu, and wherein Cu is present in the zeolite in an amount of about 0.1% to about 4.0% by weight, calculated as CuO, based on the total weight of the volatile-free calcined ion-exchanged zeolite.

[0183] 11. The catalyst composition of any one of embodiments 1 to 10, wherein the ion-exchanged palladium, calculated as elemental palladium, is present in the zeolite in an amount of about 0.01% to about 4.0% by weight, based on the total weight of the volatile-free calcined ion-exchanged zeolite.

[0184] 12. A method for NO x A catalyst product for low temperature capture and SCR, the catalyst product comprising:

[0185] substrate; and

[0186] A first washcoat material comprising a first washcoat material according to embodiments 1-11 disposed on at least a portion of a substrate.

[0187] The catalyst composition described above.

[0188] 13. The SCR catalyst article of embodiment 12, wherein the substrate is honeycomb, and wherein the honeycomb substrate is a wall flow filter or a flow-through substrate.

[0189] 14. The catalyst article of embodiment 12 or 13, wherein the catalyst article is effective in absorbing nitrogen oxides (NO) at a temperature of about 20°C to about 200°C.

[0190] 15. The catalyst article according to any one of embodiments 12 to 14, wherein the catalyst article is effective for reducing NO and NO at a temperature above about 200°C. x .

[0191] 16. The catalyst article of any one of embodiments 12 to 15, further comprising a second washcoat disposed on at least a portion of the substrate, the second washcoat comprising an SCR catalyst composition.

[0192] 17. The catalyst article according to embodiment 16, wherein the first and second washcoats are present in a zoned configuration, and wherein the second washcoat is disposed downstream of the first washcoat.

[0193] 18. The catalyst article according to any one of embodiments 12 to 17, wherein based on the NO present in the exhaust gas stream x The catalyst article effectively reduces NO in the exhaust gas stream under cold start conditions. xEmissions are reduced by at least about 10%, at least about 15%, at least about 25%, at least about 35%, at least about 45%, at least about 55%, at least about 65%, at least about 75%, at least about 85%, or at least about 95% by weight, wherein cold start conditions include an exhaust gas flow temperature of less than about 150°C.

[0194] 19. An exhaust treatment system for treating an exhaust gas flow from a lean burn engine, the exhaust treatment system comprising the catalytic article according to any one of embodiments 12 to 18 in fluid communication with the exhaust gas flow.

[0195] 20. The exhaust treatment system of embodiment 19 further comprises one or more additional components selected from the group consisting of a diesel oxidation catalyst (DOC), a soot filter, a selective catalytic reduction (SCR) catalyst, a urea injection component, an ammonia oxidation (AMO) x ) catalyst, lean NO x Capture agents (LNT) and combinations thereof.

[0196] 21. The exhaust treatment system of embodiment 19 or 20, wherein the lean burn engine is a diesel engine.

[0197] 22. A method for reducing NO in the exhaust gas flow of a lean-burn engine x A method for treating an exhaust gas stream with a catalytic article as described in any one of embodiments 12 to 18 or an exhaust gas treatment system as described in any one of embodiments 19 to 21, based on the NO present in the exhaust gas stream. x The total amount, time and temperature are sufficient to remove NO from the exhaust gas stream. x The reduction is at least about 10%, at least about 15%, at least about 25%, at least about 35%, at least about 45%, at least about 55%, at least about 65%, at least about 75%, at least about 85%, or at least about 95% by weight.

[0198] 23. A method for preparing a zeolite co-exchanged with both base metal ions and palladium ions, the method comprising contacting a zeolite comprising base metal ions with a source of palladium ions in an aqueous medium such that the palladium ions are ion-exchanged into the zeolite comprising base metal ions, thereby forming a zeolite co-exchanged with both base metal ions and palladium ions.

[0199] 24. The method of embodiment 23, further comprising drying the zeolite co-exchanged with both the base metal ions and the palladium ions; and calcining the zeolite co-exchanged with both the base metal ions and the palladium ions.

[0200] 25. A method according to embodiment 23 or 24, wherein the palladium ion source is [Pd(NH3)4][OH]2.

[0201] 26. The method of embodiment 23 or 25, wherein the base metal is Cu, Fe, or a combination thereof.

[0202] 27. The method of any one of embodiments 23 or 26, wherein at least a portion of the ion-exchanged base metal and the ion-exchanged palladium are present in ionic form within the exchange sites of the zeolite.

[0203] 28. A method according to any of embodiments 23 or 27, wherein the zeolite has a structure type selected from the group consisting of: AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, LTN, MSO, SAS, SAT, SAV, SFW, TSC, and combinations thereof.

[0204] 29. The method according to embodiments 23 to 28, wherein the zeolite has a CHA structure type.

[0205] 30. The method of any one of embodiments 23 to 29, wherein the zeolite is an aluminosilicate zeolite having a silica to alumina ratio (SAR) of about 5 to about 100.

[0206] 31. The method of embodiments 23 to 30, wherein the aluminosilicate zeolite has a SAR of about 10 to about 40.

[0207] 32. The method of any one of embodiments 23 to 31, wherein:

[0208] The ion-exchange base metal is present in the zeolite at an initial concentration;

[0209] After contacting the zeolite containing the base metal ions with a source of palladium ions in an aqueous medium, the ion-exchanged base metal is present in the zeolite at a final concentration; and

[0210] The final concentration was within about 10% of the initial concentration.

[0211] 33. The method of any one of embodiments 23 to 32, wherein the ion-exchanged palladium, calculated as elemental palladium, is present in the zeolite in an amount of about 0.01% to about 4.0% by weight, based on the total weight of the volatile-free calcined ion-exchanged zeolite.

[0212] 34. The method of any one of embodiments 23 to 33, wherein:

[0213] the ion-exchange base metal is Cu, and Cu is present in the zeolite in an amount of about 0.1% to about 4.0% by weight calculated as CuO, based on the total weight of the calcined ion-exchanged zeolite free of volatiles;

[0214] Ion-exchanged palladium, calculated as elemental palladium, is present in the zeolite in an amount of about 0.1% to about 4.0% by weight, based on the total weight of the volatile-free calcined ion-exchanged zeolite; and

[0215] At least about 50% of the Cu and at least about 50% of the palladium are present in ion exchange sites in the pore network of the zeolite.

Claims

1. A method for the determination of nitrogen oxides NO in the exhaust gas stream from a lean-burn engine x A catalyst composition for low temperature capture and selective catalytic reduction, the catalyst composition comprising a zeolite, the zeolite comprising an ion-exchanged base metal and an ion-exchanged palladium, wherein at least 50% of the ion-exchanged base metal and the ion-exchanged palladium are present in the exchange sites of the zeolite in ionic form.

2. The catalyst composition of claim 1, wherein the zeolite has a structure type selected from the group consisting of AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, LTN, MSO, SAS, SAT, SAV, SFW, TSC, and combinations thereof.

3. The catalyst composition of claim 2, wherein the zeolite has the CHA structure type.

4. The catalyst composition according to any one of claims 1 to 3, wherein the zeolite is an aluminosilicate zeolite having a silica to alumina ratio of 5 to 100.

5. The catalyst composition of claim 4, wherein the aluminosilicate zeolite has a silica to alumina ratio of 10 to 40.

6. The catalyst composition of any one of claims 1 to 3, wherein the ion-exchange base metal is selected from the group consisting of Cu, Fe, Co, Ni, La, Mn, V, Ag, Ce, Nd, Pr, Ti, Cr, Zn, Nb, Mo, Hf, Y, W, and combinations thereof.

7. The catalyst composition of any one of claims 1 to 3, wherein the ion-exchange base metal is Cu, Fe or a combination thereof.

8. The catalyst composition according to any one of claims 1 to 3, wherein the ion-exchanged base metal is present in the zeolite in an amount of 0.01 to 15% by weight calculated as base metal oxide, based on the total weight of the volatile-free calcined ion-exchanged zeolite.

9. The catalyst composition of claim 8, wherein the ion-exchange base metal is Cu, and wherein the Cu is present in the zeolite in an amount of 0.1 to 4% by weight calculated as CuO, based on the total weight of the volatile-free calcined ion-exchanged zeolite.

10. The catalyst composition of any one of claims 1 to 3, wherein the ion-exchanged palladium is present in the zeolite in an amount of 0.01% to 4% by weight calculated as elemental palladium, based on the total weight of the volatile-free calcined ion-exchanged zeolite.

11. A method for NO x A catalyst product for low temperature capture and SCR, the catalyst product comprising: substrate; and A first washcoat comprising the catalyst composition of any one of claims 1-10 disposed on at least a portion of the substrate.

12. The catalyst article of claim 11, wherein the substrate is honeycomb, and wherein the honeycomb substrate is a wall flow filter substrate or a flow-through substrate.

13. The catalyst article according to claim 11 or 12, wherein the catalyst article is effective for adsorbing nitrogen monoxide (NO) at a temperature of 20°C to 200°C.

14. The catalyst article of claim 11 or 12, wherein the catalyst article is effective for reducing NO and NO at a temperature above 200°C. x .

15. The catalyst article of claim 11 or 12, further comprising a second washcoat disposed on at least a portion of the substrate, the second washcoat comprising a selective catalytic reduction catalyst composition.

16. The catalyst article of claim 15, wherein the first washcoat and the second washcoat are present in a zoned configuration, and wherein the second washcoat is disposed downstream of the first washcoat.

17. The catalyst article of claim 11 or 12, wherein based on the NO present in the exhaust gas stream x The catalyst article effectively reduces NO in the exhaust gas stream under cold start conditions. x Emissions are reduced by at least 10% by weight, wherein the cold start conditions include an exhaust gas stream temperature below 150°C.

18. The catalyst article of claim 17, wherein based on the NO present in the exhaust gas stream x The catalyst article effectively reduces NO in the exhaust gas stream under cold start conditions. x Emissions are reduced by at least 15% by weight.

19. The catalyst article of claim 17, wherein based on the NO present in the exhaust gas stream x The catalyst article effectively reduces NO in the exhaust gas stream under cold start conditions. x Emissions are reduced by at least 25% by weight.

20. The catalyst article of claim 17, wherein based on the NO present in the exhaust gas stream x The catalyst article effectively reduces NO in the exhaust gas stream under cold start conditions. x Emissions are reduced by at least 35% by weight.

21. The catalyst article of claim 17, wherein based on the NO present in the exhaust gas stream x The catalyst article effectively reduces NO in the exhaust gas stream under cold start conditions. x Emissions are reduced by at least 45% by weight.

22. The catalyst article of claim 17, wherein based on the NO present in the exhaust gas stream x The catalyst article effectively reduces NO in the exhaust gas stream under cold start conditions. x Emissions are reduced by at least 55% by weight.

23. The catalyst article of claim 17, wherein based on the NO present in the exhaust gas stream x The catalyst article effectively reduces NO in the exhaust gas stream under cold start conditions. x Emissions are reduced by at least 65% by weight.

24. The catalyst article of claim 17, wherein based on the NO present in the exhaust gas stream x The catalyst article effectively reduces NO in the exhaust gas stream under cold start conditions. x Emissions are reduced by at least 75% by weight.

25. The catalyst article of claim 17, wherein based on the NO present in the exhaust gas stream x The catalyst article effectively reduces NO in the exhaust gas stream under cold start conditions. x Emissions are reduced by at least 85% by weight.

26. The catalyst article of claim 17, wherein based on the NO present in the exhaust gas stream x The catalyst article effectively reduces NO in the exhaust gas stream under cold start conditions. x Emissions are reduced by at least 95% by weight.

27. An exhaust treatment system for treating an exhaust gas stream from a lean burn engine, the exhaust treatment system comprising a catalyst article according to any one of claims 11 to 26 in fluid communication with the exhaust gas stream.

28. The exhaust treatment system of claim 27, further comprising one or more additional components selected from the group consisting of a diesel oxidation catalyst, a soot filter, a selective catalytic reduction catalyst, a urea injection component, an ammonia oxidation catalyst, a lean NO x Capture agents and combinations thereof.

29. An exhaust treatment system according to claim 27 or 28, wherein the lean burn engine is a diesel engine.

30. A method for reducing NO in the exhaust gas flow of a lean-burn engine x A method for treating the exhaust gas stream with a catalyst article according to any one of claims 11 to 26 or an exhaust gas treatment system according to any one of claims 27 to 29, based on the NO present in the exhaust gas stream. x The total amount, time and temperature are sufficient to remove NO from the exhaust gas stream. x The level was reduced by at least 10% by weight.

31. The method of claim 30, based on the presence of NO in the exhaust gas stream. x The total amount, time and temperature are sufficient to remove NO from the exhaust gas stream. x The level was reduced by at least 15% by weight.

32. The method of claim 30, based on the presence of NO in the exhaust gas stream. x The total amount, time and temperature are sufficient to remove NO from the exhaust gas stream. x The level was reduced by at least 25% by weight.

33. The method of claim 30, based on the presence of NO in the exhaust gas stream. x The total amount, time and temperature are sufficient to remove NO from the exhaust gas stream. x The level was reduced by at least 35% by weight.

34. The method of claim 30, based on the presence of NO in the exhaust gas stream. x The total amount, time and temperature are sufficient to remove NO from the exhaust gas stream. x The level was reduced by at least 45% by weight.

35. The method of claim 30, based on the presence of NO in the exhaust gas stream. x The total amount, time and temperature are sufficient to remove NO from the exhaust gas stream. x The level was reduced by at least 55% by weight.

36. The method of claim 30, based on the presence of NO in the exhaust gas stream. x The total amount, time and temperature are sufficient to remove NO from the exhaust gas stream. x The level was reduced by at least 65% by weight.

37. The method of claim 30, based on the presence of NO in the exhaust gas stream. x The total amount, time and temperature are sufficient to remove NO from the exhaust gas stream. x The level was reduced by at least 75% by weight.

38. The method of claim 30, based on the presence of NO in the exhaust gas stream. x The total amount, time and temperature are sufficient to remove NO from the exhaust gas stream. x The level was reduced by at least 85% by weight.

39. The method of claim 30, based on the presence of NO in the exhaust gas stream. x The total amount, time and temperature are sufficient to remove NO from the exhaust gas stream. x The levels were reduced by at least 95% by weight.

40. A method for preparing a zeolite co-exchanged with both base metal ions and palladium ions, the method comprising contacting a zeolite comprising the base metal ions with a source of palladium ions in an aqueous medium such that the palladium ions are ion-exchanged into the zeolite comprising the base metal ions, thereby forming the zeolite co-exchanged with both base metal ions and palladium ions, At least 50% of the ion-exchange base metal and the ion-exchange palladium are present in ionic form within the exchange sites of the zeolite.

41. The method of claim 40, further comprising drying the zeolite co-exchanged with both base metal ions and palladium ions; and calcining the zeolite co-exchanged with both base metal ions and palladium ions.

42. A method according to claim 40 or 41, wherein the source of palladium ions is [Pd(NH3)4][OH]2.

43. The method of claim 40 or 41, wherein the base metal is Cu, Fe or a combination thereof.

44. The method of claim 40 or 41, wherein the zeolite has a structure type selected from the group consisting of AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, LTN, MSO, SAS, SAT, SAV, SFW, TSC, and combinations thereof.

45. The method of claim 44, wherein the zeolite has the CHA structure type.

46. ​​The method of claim 40 or 41, wherein the zeolite is an aluminosilicate zeolite having a silica to alumina ratio of 5 to 100.

47. The method of claim 46, wherein the aluminosilicate zeolite has a silica to alumina ratio of 10 to 40.

48. The method of claim 40 or 41, wherein: The ion-exchange base metal is present in the zeolite at an initial concentration; After contacting the zeolite comprising base metal ions with the source of palladium ions in an aqueous medium, the ion-exchange base metal is present in the zeolite at a final concentration; and The final concentration was within 10% of the initial concentration.

49. The process of claim 40 or 41, wherein the ion-exchanged palladium is present in the zeolite in an amount of 0.01% to 4.0% by weight calculated as elemental palladium, based on the total weight of the volatile-free calcined ion-exchanged zeolite.

50. The method of claim 40 or 41, wherein: the ion-exchange base metal is Cu, and the Cu is present in the zeolite in an amount of 0.1 to 4.0% by weight calculated as CuO, based on the total weight of the calcined ion-exchanged zeolite free of volatiles; said ion-exchanged palladium, calculated as elemental palladium, is present in said zeolite in an amount of 0.1% to 4.0% by weight, based on the total weight of the calcined ion-exchanged zeolite free of volatiles; as well as At least 50% of the Cu and at least 50% of the palladium are present in the ion exchange sites in the pore network of the zeolite.

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