Exhaust treatment system for ammonia-fueled vehicle

Abstract

The present disclosure relates to an emissions treatment system for reducing NOx in an exhaust stream of an ammonia-fueled engine, the emissions treatment system comprising: a selective catalytic reduction (SCR) catalyst disposed on a substrate in fluid communication with the exhaust stream; an oxidation catalyst disposed on a substrate located upstream or downstream of the SCR catalyst and in fluid communication with the exhaust stream and the SCR catalyst; and optionally one or more adsorption components disposed on a substrate located upstream and / or downstream of the SCR catalyst and in fluid communication with the exhaust stream and the SCR catalyst, the adsorption components selected from the group consisting of a low temperature NOx adsorbent (LT-NA), a low temperature ammonia adsorbent (LT-AA), a low temperature water vapor adsorbent (LT-WA), and combinations thereof. An associated method of treating exhaust gas is also provided.

Description

[0001] The present disclosure relates to a method suitable for treating the exhaust gas stream of an ammonia fueled internal combustion engine to reduce nitrogen oxides (NO x )Emission compositions, components, emission treatment systems and methods.

[0002] In order to reduce greenhouse gas emissions such as CO 2 Emissions, environmental regulations around the world regarding internal combustion engine emissions are becoming increasingly stringent. Vehicle manufacturers are increasingly focusing on engines that utilize fuels other than traditional hydrocarbon-based fuels. Electric vehicles and hydrogen-powered vehicles have received much attention in recent years, but these engine systems have not yet been widely implemented. Both electric engine systems and hydrogen engine systems have certain disadvantages, including safety issues associated with high-pressure storage of hydrogen, the weight of the battery pack, and the fact that the electricity required for electric engines is typically generated using fossil fuels.

[0003] One of the least intrusive ways to achieve greenhouse gas reductions is to change the fuel from gasoline / diesel to ammonia, a non-hydrocarbon fuel. Ammonia is one of only a few compounds that is liquid at room temperature, releases energy quickly when burned and provides a high energy volume density.

[0004] Ammonia is made up of only hydrogen and nitrogen atoms. Therefore, when burned, ammonia will not release carbon dioxide, carbon monoxide, or other greenhouse pollutants. Emissions from burning ammonia are typically nitrogen and water vapor. More specifically, the complete combustion of ammonia can be described by the following equation:

[0005] 4NH 3 +3O 2 + Heat → 2N 2 +6H 2 O.

[0006] [ΔH° r = -1267.20 kJ / mol (or if expressed in terms of NH 3 = -316.8 kJ / mol)]

[0007] However, some unburned NH 3 And some trace amounts of over-combustion products may appear such as through the following reactions:

[0008] 4NH 3 +5O 2 →4NO+6H 2 O

[0009] Since the heating value (energy content) of ammonia is approximately 20% lower than diesel on a volume basis, more ammonia fuel is required to generate the same power as a diesel fueled vehicle. It is therefore highly desirable to provide an emissions treatment system that provides effective NOx reduction for, for example, an ammonia fueled engine.

[0010] The present disclosure relates to methods for reducing NO in the exhaust stream of an ammonia fueled engine. x In some embodiments, such a system can effectively reduce not only the NO associated with such an engine, but also the x emissions, and can effectively adsorb certain gaseous components of the exhaust stream emitted by such engines to enhance the effectiveness of the system. In some embodiments, the emission treatment system of the present disclosure can combine a selective catalytic reduction (SCR) catalyst with an oxidation catalyst located upstream or downstream of the SCR catalyst. In other embodiments, the emission treatment system of the present disclosure can combine a selective catalytic reduction (SCR) catalyst and an oxidation catalyst with one or more adsorption components selected from low temperature NO x adsorbent (LT-NA), low temperature ammonia adsorbent (LT-AA) and low temperature water vapor adsorbent (LT-WA).

[0011] The present disclosure includes, but is not limited to, the following embodiments.

[0012] Embodiment 1: An emission treatment system for reducing NOx in an exhaust stream of an ammonia fueled engine, the emission treatment system comprising:

[0013] a selective catalytic reduction (SCR) catalyst disposed on a substrate in fluid communication with the exhaust stream of the ammonia fueled engine; and

[0014] An oxidation catalyst is disposed on a substrate upstream and / or downstream of the SCR catalyst and in fluid communication with the exhaust gas flow and the SCR catalyst.

[0015] Embodiment 2: The emissions treatment system of Embodiment 1, wherein the oxidation catalyst comprises a refractory metal oxide support impregnated with a platinum group metal (PGM).

[0016] Embodiment 3: The emission treatment system of Embodiment 2, wherein the PGM comprises platinum, palladium, rhodium, or a combination thereof.

[0017] Embodiment 4: The emissions treatment system of any one of Embodiments 2-3, wherein the oxidation catalyst further comprises a refractory metal oxide support impregnated with a non-PGM transition metal, an alkaline earth metal, or a combination thereof.

[0018] Embodiment 5: The emission treatment system of Embodiment 4, wherein the non-PGM transition metal comprises manganese.

[0019] Embodiment 6: The emission treatment system of any one of Embodiments 4 to 5, wherein the alkaline earth metal comprises barium

[0020] Embodiment 7: The emission treatment system of any one of Embodiments 1 to 6, wherein the oxidation catalyst is selected from a diesel oxidation catalyst, DOC, and a selective ammonia oxidation catalyst, AMOx.

[0021] Embodiment 8: The emissions treatment system of any one of Embodiments 1 to 7, wherein the SCR catalyst comprises a metal-promoted molecular sieve, a vanadium oxide-based composition, or a combination thereof.

[0022] Embodiment 9: The emission treatment system of any one of Embodiments 1 to 8, wherein the SCR catalyst is a copper-containing zeolite, an iron-containing zeolite, or a manganese-containing zeolite.

[0023] Embodiment 10: The emission treatment system of Embodiment 9, wherein the zeolite has a framework type selected from LEV, CHA, AEI, MEI, FER, *BEA, FAU, or combinations thereof.

[0024] Embodiment 11: The emission treatment system of any one of Embodiments 1 to 10, wherein the SCR catalyst and the oxidation catalyst are present in the form of an SCR / AMOx catalyst.

[0025] Embodiment 12: The emission treatment system according to any one of Embodiments 1 to 11, further comprising one or more adsorption components, wherein the one or more adsorption components are selected from low temperature NO x Adsorbent LT-NA, low temperature ammonia adsorbent LT-AA, low temperature water vapor adsorbent LT-WA or a combination thereof.

[0026] Embodiment 13: The emission treatment system of Embodiment 12, wherein the one or more adsorption components are arranged in any order and combination.

[0027] Embodiment 14: An emission treatment system according to any one of Embodiments 12 to 13, wherein each of the one or more adsorption components is disposed on a substrate located upstream or downstream of the SCR catalyst and in fluid communication with the exhaust gas flow and the SCR catalyst.

[0028] Embodiment 15: The emission treatment system of any one of Embodiments 12 to 14, wherein each of the one or more adsorbent components is disposed on the same substrate in a mixture, in a partitioned configuration, or in a layered configuration.

[0029] Embodiment 16: An emission treatment system according to any one of Embodiments 12 to 15, wherein the SCR catalyst, the oxidation catalyst and one or more of the one or more adsorption components are arranged on the same substrate in the form of a mixture, in a partitioned structure or in a layered structure.

[0030] Embodiment 17: The emission treatment system of any one of Embodiments 12 to 16, wherein the one or more adsorbent components and the DOC are disposed on the same substrate in a mixture, in a zoned configuration, or in a layered configuration.

[0031] Embodiment 18: The emission treatment system according to any one of Embodiments 1 to 17, further comprising one or more additional SCR catalysts, one or more additional oxidation catalysts, or a combination thereof.

[0032] Embodiment 19: The emission treatment system of embodiment 18, wherein starting from the emission treatment component closest to the engine, the emission treatment system comprises one of the following arrangements in order:

[0033] (a) Adsorption components, DOC, SCR catalyst and AMOx;

[0034] (b) SCR, adsorption components, DOC and AMOx;

[0035] (c) adsorption components, SCR catalyst, DOC, SCR catalyst and AMOx;

[0036] (d) Adsorption components, SCR catalyst and AMOx;

[0037] (e) Adsorption components, DOC and SCR catalyst;

[0038] (f) SCR catalyst, AMOx and adsorption components;

[0039] (g) SCR catalyst and AMOx;

[0040] (h) DOC and SCR catalyst; or

[0041] (i) SCR catalyst, SCR catalyst and AMOx.

[0042] Embodiment 20: The emission treatment system of any one of Embodiments 12 to 19, wherein the LT-NA is present and comprises a molecular sieve or a metal organic framework (MOF) impregnated with at least one platinum group metal component.

[0043] Embodiment 21: The emission treatment system of any one of Embodiments 12 to 20, wherein the LT-AA is present and comprises a molecular sieve or a MOF.

[0044] Embodiment 22: The emission treatment system of any one of Embodiments 12 to 21, wherein the LT-WA is present and is selected from the group consisting of molecular sieves, clays, activated carbon, activated alumina, silica, calcium sulfate, calcium chloride, MOFs, and combinations thereof.

[0045] Embodiment 23: An emission treatment system according to any one of Embodiments 12 to 22, wherein the SCR catalyst, the one or more adsorption components and one or more of the oxidation catalysts are disposed on a flow-through substrate in a honeycomb form, the substrate having a plurality of longitudinally extending airflow channels extending from an inlet to an outlet, and / or wherein the SCR catalyst, the one or more adsorption components and one or more of the oxidation catalysts are disposed on a wall-flow substrate or optionally on a metal substrate having flow-through channels, wherein a portion of the exhaust gas is fluidly connected between the channels.

[0046] Embodiment 24: A method for reducing NOx in an exhaust stream of an ammonia fueled engine, the method comprising contacting the exhaust stream with an emissions treatment system according to any one of Embodiments 1 to 23.

[0047] By reading the following detailed description and the accompanying drawings briefly described below, these and other features, aspects and advantages of the present disclosure will become apparent. The present disclosure includes any combination of two, three, four or more embodiments in the above-mentioned embodiments and any combination of two, three, four or more features or elements set forth in the present disclosure, regardless of whether such features or elements are clearly combined in the embodiment description herein. The present disclosure is intended to be read as a whole so that any separable features or elements in any aspect and embodiment of the various aspects and embodiments of the present disclosure should be considered to be intended to be combinable, unless the context clearly indicates otherwise.

[0048] In order to provide an understanding of the embodiments of the present disclosure, reference is made to the accompanying drawings, in which reference numerals refer to components of exemplary embodiments of the present disclosure. Such drawings are illustrative 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 description, the features illustrated in the accompanying drawings are not necessarily drawn to scale. In addition, where deemed appropriate, reference numerals are repeated in the accompanying drawings to indicate corresponding or similar elements.

[0049] Figure 1ADepicted is a perspective view of an exemplary honeycomb substrate that may include a composition washcoat according to some exemplary embodiments.

[0050] Figure 1B Depicted are exemplary embodiments in which the substrate is a flow-through substrate relative to Figure 1A Zoom in and follow the Figure 1A A partial cross-sectional view taken through a plane of the end surface of the substrate, showing Figure 1A An enlarged view of the multiple air flow channels shown in FIG.

[0051] Figure 2 Depicts relative to Figure 1A A cross-sectional view of an enlarged section, wherein Figure 1A The honeycomb-type substrate in represents an exemplary wall-flow filter.

[0052] Figure 3 A schematic diagram of an exemplary embodiment of an emissions treatment system is depicted.

[0053] Figure 4 Plotted are traces of DOC inlet temperature, DOC outlet temperature, SCR inlet temperature, and space velocity (SV) under various scenarios for an exemplary embodiment of the exhaust gas treatment system of the present disclosure.

[0054] Figure 5 Depicted Figure 4 Inlet NOx trace of an exemplary embodiment of FIG.

[0055] Figure 6 Describes the following DOC or Figure 4 NOx conversion under various scenarios following an exemplary embodiment of the present invention.

[0056] Figure 7 Depicted are NOx conversions under various scenarios after a zoned LTNA-DOC or a stratified LTNA-DOC or after an exemplary embodiment of the exhaust gas treatment system of the present disclosure.

[0057] Figure 8 Cumulative NOx emissions following an exemplary embodiment of the exhaust gas treatment system of the present disclosure are depicted.

[0058] Fig. 9 NOx conversion following an exemplary embodiment of the exhaust gas treatment system of the present disclosure is depicted.

[0059] Fig.10 Plotted are traces of inlet temperature, outlet temperature, and space velocity (SV) for various scenarios for an exemplary embodiment of the exhaust gas treatment system of the present disclosure.

[0060] Fig.11Overall NOx conversion for an exemplary embodiment of the exhaust gas treatment system of the present disclosure is depicted.

[0061] Fig.12 An inlet NO of an exemplary embodiment of an exhaust gas treatment system of the present disclosure is depicted. x and export NO x Emission curve.

[0062] Fig.13 Inlet NOx and outlet NOx emissions curves are depicted for an exemplary embodiment of the exhaust gas treatment system of the present disclosure.

[0063] Fig.14 Cumulative NOx emissions for an embodiment of an exhaust gas treatment system of the present disclosure are depicted, with the inset depicting an air to fuel ratio (λ) with a graph cutoff of 2.00.

[0064] The present disclosure will now be described more fully below. However, the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; on the contrary, these embodiments are provided so that the present disclosure will be complete and complete and fully convey the scope of the present disclosure to those skilled in the art.

[0065] definition

[0066] As used herein, unless otherwise specified, "a" or "an" entity refers to one or more of the entity, for example, "a compound" refers to one or more compounds or at least one compound. Therefore, the terms "a" (or "one"), "one or more" and "at least one" are used interchangeably herein.

[0067] Any ranges cited herein are inclusive. The term "about" used throughout is used to describe and illustrate small variations. For example, "about" can mean that a numerical value can be modified by ±5%, ±4%, ±3%, ±2%, ±1%, ±0.5%, ±0.4%, ±0.3%, ±0.2%, ±0.1%, or ±0.05%. Numerical values ​​modified by the term "about" include specific identified values. For example, "about 5.0" includes 5.0.

[0068] The term "abatement" means a decrease in amount caused by any means.

[0069] The term "adsorbent" refers to a material that adsorbs and / or absorbs a desired substance. Advantageously, an adsorbent can adsorb and / or absorb (store) a substance at a particular temperature and desorb (release) the substance at a higher temperature.

[0070] The term "ammonia fuel engine" as used in this specification and claims is an engine capable of converting ammonia into its final oxidation products and releasing its latent heat energy by doing so (i.e., converting chemical energy into mechanical (work) energy). Therefore, this engine can be operated with any mixed fuel, such as a blended fuel including gasoline and ammonia, or a blended fuel of diesel and ammonia, or a mixture of 10% alcohol (ethanol) in gasoline and ammonia, or a mixture of ammonia and any biofuel, as long as the fuel includes ammonia.

[0071] The term "associated" means, for example, "equipped with," "connected to," or "in communication with," such as "electrically connected" or "in fluid communication with," or otherwise connected in a functional manner. The term "coupled" may mean directly coupled or indirectly coupled, such as through one or more other articles or elements.

[0072] The term "catalyst" refers to a material that promotes a chemical reaction. A catalyst includes a "catalytically active substance" and a "support" that carries or supports the active substance. For example, zeolite can be a support for a palladium-active catalytic substance. Similarly, refractory metal oxide particles can be a support for a platinum group metal catalytic substance. Catalytically active substances are also called "promoters" because they promote chemical reactions.

[0073] The term "catalytic article" in this disclosure means an article comprising a substrate having a catalyst coating composition.

[0074] The term "configured" as used in this specification and claims is intended to be an open term, just like the terms "comprising" or "containing." The term "configured" is not intended to exclude other possible articles or elements. The term "configured" may be equivalent to "adapted."

[0075] Generally, with respect to a specified catalytic activity or storage / release activity, the term "effective" means on a weight or molar basis, for example, about 35% to 100% effective, for example, 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% effective.

[0076] The term "exhaust stream" or "exhaust gas stream" refers to any combination of flowing gases that may contain solid or liquid particulate matter. The stream includes gaseous components and may be, for example, the exhaust gas of a lean-burn engine that may contain certain non-gaseous components such as liquid droplets, solid particles, etc. The exhaust stream of a combustion engine may also include, for example, combustion products (CO 2 and H2 O), incomplete combustion products (carbon monoxide (CO) and hydrocarbons), nitrogen oxides (NO x ), combustible and / or carbonaceous particulate matter (soot), and unreacted oxygen and nitrogen. In certain embodiments, in an ammonia fueled engine, the exhaust stream may consist of nitrogen, water vapor, and a small amount of NOx. However, in a dual fuel system, some of the other materials mentioned above may be present, but in smaller amounts than in conventional engines.

[0077] As used herein, the terms "upstream" and "downstream" refer to the relative directions of flow from the engine to the tail pipe according to the engine exhaust stream, wherein the engine is in an upstream position, and the tail pipe and any pollution reduction products such as filters and catalysts are 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, and the downstream zone can be farther away from the engine or manifold.

[0078] The term "in fluid communication" is used to refer to articles being located in the same exhaust line, i.e., a common exhaust flow passes through the articles that are in fluid communication with each other. The articles in fluid communication may be adjacent to each other in the exhaust line. Alternatively, the articles in fluid communication may be separated by one or more articles (also referred to as "washcoated monoliths").

[0079] As used herein, "impregnated" or "impregnation" refers to the penetration of the catalytic material into the porous structure of the support material.

[0080] The terms "on" and "over" and "overlapping" with respect to coating layers may be used synonymously. The term "directly on" means in direct contact with. In certain embodiments, the disclosed articles are referred to as including one coating layer "on" a second coating layer, and such language is intended to encompass embodiments with intermediate layers, where direct contact between coating layers is not required (i.e., "on" is not equivalent to "directly on").

[0081] As used herein, the terms "nitrogen oxides" and "NO x " indicates nitrogen oxides, such as NO, NO 2 or N 2 O.

[0082] "Substantially free" means "little or no" or "not intentionally added", and also allows for only trace and / or unintentional amounts. For example, in certain embodiments, "substantially free" means less than 2 wt% (weight %), less than 1.5 wt%, less than 1.0 wt%, less than 0.5 wt%, less than 0.25 wt%, or less than 0.01 wt%, based on the weight of the indicated total composition.

[0083] As used herein, the term "washcoat" has its usual meaning in the field of a thin adherent coating of a catalytic material or other material applied to a substrate material such as a honeycomb substrate that is porous enough to allow the treated airflow to pass. As used herein and as described in Heck, Ronald and Farrauto, Robert, Catalytic Air Pollution Control, New York: Wiley-Interscience, 2002, pages 18-19, a washcoat layer includes a compositionally different material layer disposed on the surface of a monolithic substrate or an underlying washcoat layer. The substrate may contain one or more washcoat layers, and each washcoat layer may differ in some respects (e.g., may differ in its physical properties such as particle size or microcrystalline phase) and / or may differ in chemical catalytic function. The washcoat is, for example, a slurry of a catalyst containing a specified solid content (e.g., 30% to 90% by weight) in a liquid, which is then coated on a substrate and dried to obtain a washcoat layer.

[0084] If not otherwise indicated, "weight percent (wt%)" is based on the entire composition excluding any volatiles, ie, based on dry solids content. Unless otherwise indicated, all parts and percentages are by weight.

[0085] Unless otherwise specified herein or clearly contradictory to the context, all methods described herein may be performed in any suitable order. Unless otherwise stated, 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 is not intended to limit the scope. The language in this specification should not be interpreted as indicating that any unclaimed element is necessary for the practice of the materials and methods of the present disclosure. All U.S. patent applications, pre-authorization publications, and patents mentioned herein are hereby incorporated by reference in their entirety.

[0086] Emissions treatment systems

[0087] In the first aspect, the emission treatment system can be suitable for an ammonia fuel internal combustion engine including a dual fuel system. Ammonia combustion engine systems are known in the art and are shown in, for example, U.S. Patent Nos. 8,464,515; 8,904,994; and 9,341,111 and U.S. Publication Nos. 2011 / 0265463; 2011 / 0283684; and 2018 / 0100469, all of which are incorporated herein by reference. Such engines are similar to other types of combustion engines and may include an engine body, a cylinder block, one or more cylinder heads, one or more pistons, one or more combustion chambers, one or more spark plugs (e.g., plasma jet spark plugs) arranged at the top surface of each combustion chamber, an intake valve, an intake port, an exhaust valve, and an exhaust port. Each air inlet can be connected to the ammonia injector fluid for injecting ammonia, and in the dual fuel system that is sometimes used to enhance the ignition properties of the ammonia fuel engine, the air inlet can also be connected to the secondary combustible fuel such as hydrocarbon fuel or hydrogen fluid. In some ammonia fuel engines, the exhaust gas containing ammonia from the combustion chamber passes through a reforming or cracking catalyst to produce hydrogen, and then the hydrogen is fed back to the air inlet to enhance the ignition properties of the engine. In certain embodiments, the ammonia fuel engine can only utilize ammonia as a combustion fuel. In other embodiments, the ammonia fuel engine is a dual fuel engine utilizing ammonia and one or more additional combustion fuels (e.g., hydrogen or hydrocarbon fuels).

[0088] In certain embodiments, the emission treatment system combines an SCR catalyst for reducing NOx in the exhaust gas stream with an SCR catalyst suitable for adsorbing water, NOx, and NH 3 A combination of one or more adsorbents of one or more of the above. An SCR catalyst is needed to reduce NOx that may be produced by the combustion of ammonia under certain operating conditions. The emission treatment system also includes an oxidation catalyst. In some embodiments, the oxidation catalyst is an ammonia oxidation catalyst (AMOx) for oxidizing any residual ammonia in the exhaust stream (or trace CO or hydrocarbon fuels in a dual-fuel engine). In some embodiments, the oxidation catalyst is a diesel oxidation catalyst for oxidizing CO and / or hydrocarbon substances such as from a dual-fuel engine into carbon dioxide and water vapor. In a single-fuel NH 3 In an engine, a DOC catalyst may be incorporated into an emission treatment system to oxidize trace amounts of hydrocarbon species, such as engine lubricants or feedstock impurities, which may also include the exhaust stream. In some embodiments, an emission treatment system may include one or more oxidation catalysts, such as DOC and AMOx.

[0089] In certain embodiments, the water adsorbent may be used to prevent water condensation within the emission treatment system during low temperature (e.g., cold start) conditions, which may impair catalyst function and / or hinder NOx adsorption. In certain embodiments, it is advantageous to position the water adsorbent upstream of the NOx adsorbent to enhance the effectiveness of NOx adsorption. In certain embodiments, the NOx adsorbent and NH 3 The adsorbents can be used to separate NOx or NH during low temperature conditions. 3 Until the exhaust temperature is high enough to obtain effective SCR catalyst performance.

[0090] Figure 3 An exemplary exhaust treatment system is shown in , which depicts a schematic diagram of a non-limiting exhaust treatment system according to an exemplary embodiment of the present disclosure. As shown, the exhaust treatment system 20 may include a plurality of components connected in series downstream of an engine 22, such as an ammonia fueled engine. Figure 3 Five components are shown: 24, 26, 28, 30, 32 in series; however, the total number of components may vary, and five components is only an example. Figure 3 For simplicity, each component is described as a "catalyst component", but not every component necessarily includes a catalyst. For example, some components may consist of an adsorption composition.

[0091] Without limitation, Table 1 presents various exhaust treatment system configurations for one or more exemplary embodiments. It should be noted that each component is connected to the next component via an exhaust conduit such that the engine is upstream of component A, component A is upstream of component B, component B is upstream of component C, component C is upstream of component D, and component D is upstream of component E (when present). References to components A through E in this table may be made to Figure 3 The same reference numerals in the text are cross-referenced.

[0092] As recognized by those skilled in the art, Table 1 is a non-exhaustive list of configurations, and any one or more of components A, B, C, D, or E may be disposed on the same or different substrates, such as a particulate filter, such as a wall-flow filter, or on a flow-through honeycomb substrate. In some embodiments, each of the components of the engine exhaust system is on the same substrate. In some embodiments, more than one substrate may be used for the components of the engine exhaust system.

[0093] In one or more embodiments, the engine exhaust system includes one or more components installed in a position near the engine (closely coupled position CC) and an additional component in a position below the vehicle body (underfloor position UF). The reductant used for the SCR catalyst herein includes ammonia. Ammonia can be provided by a separate injection line in front of the SCR catalyst, or ammonia can be provided by releasing stored ammonia in LT-AA, or by a combination of the above.

[0094] In one or more embodiments, the exhaust gas treatment system may also include an ammonia or ammonia precursor injection component, for example, placed upstream of any SCR catalyst present in the system. In Table 1, the adsorbent components may include a low temperature NOx adsorbent (LT-NA), a low temperature NH 3 Adsorbent (LT-AA), low temperature H 2 O (water vapor) adsorbent (LT-WA), or a combination thereof. "SCR" refers to a selective catalytic reduction catalyst, DOC refers to a diesel oxidation catalyst, and "AMOx" refers to an ammonia oxidation catalyst, all of which are described in more detail below.

[0095] Table 1. Possible exhaust treatment system configurations

[0096] Component A Component B Component C Component D Component E DOC SCR - - - SCR AMOx - - - Adsorption components SCR AMOx - - SCR AMOx Adsorption components - - SCR SCR AMOx Adsorption components SCR SCR AMOx SCR SCR AMOx Adsorption components Adsorption components DOC SCR - - Adsorption components DOC SCR AMOx - SCR Adsorption components DOC AMOx - Adsorption components SCR DOC SCR AMOx

[0097] The adsorbent components may be in any order and in any combination. For example, the adsorbent components of the emission treatment system of the present disclosure may be LT-AA; LT-WA; LT-NA; LT-AA, LT-WA; LT-AA, LT-NA; LT-WA, LT-NA; LT-WA, LT-NA, LT-AA; LT-NA, LT-WA, LT-AA; LT-WA, LT-A, LT-NA; LT-AA, LT-NA, LT-WA. In some embodiments, the adsorbent components may be disposed on the same or different substrates. For example, the emission treatment system of the present disclosure may include LT-AA, LT-NA, and LT-WA on the same substrate; LT-NA and LT-WA disposed on the same substrate and LT-AA on different substrates; and LT-NA and LT-AA disposed on the same substrate.

[0098] SCR catalyst composition

[0099] In certain embodiments, the SCR catalyst composition comprises a metal-promoted molecular sieve, a vanadium oxide-based composition, or a combination thereof. In certain embodiments, the SCR catalyst composition comprises a metal-promoted (e.g., Cu-promoted, Fe-promoted, or Cu / Fe-promoted) molecular sieve. As used herein, the phrase "molecular sieve" refers to a framework material that can be used as a catalyst in particulate form, such as zeolites and other framework materials (e.g., isomorphously substituted materials) 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, wherein the average pore size is no greater than The pore size is limited by the ring size. As used herein, the term "zeolite" refers to a specific example of a molecular sieve that also includes silicon atoms and aluminum atoms. According to one or more embodiments, it should be understood that the molecular sieve is intended to include a molecular sieve with the structure type and any and all isotype framework materials such as SAPO, AlPO and MeAPO materials with the same structure type by defining the structure type of the molecular sieve.

[0100] In some embodiments, reference to the aluminosilicate zeolite structure type limits the material to molecular sieves that do not intentionally include phosphorus or other metals substituted in the framework. For clarity, as used herein, "aluminosilicate zeolite" does not include aluminophosphate materials such as SAPO, ALPO and MeAPO materials, and the broader term "zeolite" is intended to include aluminosilicates and aluminophosphates. Zeolites are crystalline materials and are understood to be aluminosilicates with an open 3-dimensional framework structure consisting of corner-sharing TOs. 4 Tetrahedron, wherein T is Al or Si. Zeolites generally contain a silicon dioxide to alumina (SAR) molar ratio of 2 or greater. The zeolites used in the disclosed catalyst compositions are not particularly limited in terms of SAR values, but in some embodiments, the specific SAR values ​​associated with the zeolites may affect the SCR performance of the catalyst compositions incorporating the zeolites (e.g., particularly after aging). In some embodiments, the SAR value of the zeolite is from about 5 to about 100 or from about 5 to about 50. In some embodiments, the SAR is from about 5 to about 20, and in other embodiments, the SAR is from about 20 to about 50.

[0101] The cations that balance the charge of the anionic framework are loosely associated with the framework oxygens, and the remaining pore volume may be filled with water molecules. Non-framework cations are generally exchangeable, and the water molecules are removable. Zeolites can have fairly uniform pore sizes ranging from about 3 angstroms to about 10 angstroms in diameter, depending on the type of zeolite and the type and amount of cations included in the zeolite lattice.

[0102] Molecular sieves can be classified by identifying the framework topology of the structure. For example, any structure type of zeolite can be used, such as the following structure types: ABW, ACO, AEI, AEL, AEN, AET, AFG, AFI, AFN, AFO, AFR, AFS, AFT, AFX, AFY, AHT, ANA, APC, APD, AST, ASV, ATN, ATO, ATS, ATT, ATV, AWO, AWW, BCT, *BEA, BEC, BIK, BOG, BPH, BRE, CAN, CAS, SCO, CFI, SGF, CGS, CHA, CHI, CLO, CON, CZP, DAC, DDR, DFO, DFT, DOH, DON, EAB, EDI, EMT, EON, EPI, ERI, ESV , ETR, EUO, FAU, FER, FRA, GIS, GIU, GME, GON, GOO, HEU, IFR, IHW, ISV, ITE, ITH, ITW, IWR, IWW, JBW, KFI, LAU , LEV, LIO, LIT, LOS, LOV, LTA, LTL, LTN, MAR, MAZ, MEI, MEL, MEP, MER, MFI, MFS, MON, MOR, MOZ, MSO, MTF, MT N, MTT, MTW, MWW, NAB, NAT, NES, NON, NPO, NSI, OBW, OFF, OSI, OSO, OWE, PAR, PAU, PHI, PON, RHO, RON, RRO, RS , 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. In certain embodiments, the structure type is selected from AEI, AFT, AFV, AFX, AVL, CHA, DDR, EAB, EEI, ERI, IFY, IRN, KFI, LEV, LTA, LTN, MER, MWF, NPT, PAU, RHO, RTE, RTH, SAS, SAT, SAV, SFW, TSC, UFI and a combination thereof. For example, the existing symbionts of these materials including but not limited to AEI-CHA are also intended to be included herein. In certain embodiments, the zeolite of the SCR catalyst has a framework type selected from LEV, CHA, AEI, MEI, FER, or combinations thereof.

[0103] Zeolite is made up of secondary building units (SBU) and composite building units (CBU), and appears in many different framework structures. Secondary building units contain up to 16 tetrahedral atoms and are achiral. Composite building units do not need to be achiral, and may not necessarily be used to build the entire framework. For example, a group of zeolites can have a single 4-ring (S4R) composite building unit in its framework structure. In the 4-ring, "4" represents the position of the tetrahedral silicon atom and the aluminum atom, and the oxygen atom is located between the tetrahedral atoms. Other composite building units include, for example, single 6-ring (S6R) units, double 4-ring (D4R) units, and double 6-ring (D6R) units. The D4R unit is created by connecting two S4R units. The D6R unit is created by connecting two S6R units. In the D6R unit, there are twelve tetrahedral atoms. Zeolite structure types with d6r secondary building units include AEI, AFT, AFX, CHA, EAB, EMT, ERI, FAU, GME, JSR, KFI, LEV, LTL, LTN, MOZ, MSO, MWW, OFF, SAS, SAT, SAV, SBS, SBT, SFW, SSF, SZR, TSC, WEN and combinations thereof. In one or more embodiments of the present disclosure, the molecular sieve of the catalyst composition has a CHA structure type. In other embodiments, the molecular sieve has a CHA structure type and is selected from the group consisting of SSZ-13, SSZ-62, natural chabazite, zeolite KG, Linde D, Linde R, LZ-218, LZ-235, LZ-236, ZK-14, SAPO-34, SAPO-44, SAPO-47, ZYT-6 and combinations thereof.

[0104] In certain embodiments, the zeolite of catalyst composition includes small pore zeolite. Small pore zeolite contains the channel limited by up to eight tetrahedral atoms.Phrase " 8 rings " zeolite refers to the zeolite with 8 ring hole openings, and in some cases, " 8 rings " zeolite can also include double six rings secondary building blocks and can have the cage structure produced by double six rings building blocks connected by 4 rings.Exemplary small pore zeolite includes framework type 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 their mixture or symbiont. For example, in certain embodiments, the zeolite comprises a small pore zeolite having a framework type selected from CHA, LEV, AEI, AFT, AFX, ERI, SFW, KFI, DDR, ITE, and mixtures or intergrowths thereof.

[0105] In certain embodiments, the zeolite of the disclosed catalyst composition includes a mesoporous zeolite. The mesoporous zeolite contains a channel limited by a ten-membered ring. Exemplary mesoporous 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 symbionts thereof. For example, in certain embodiments, the zeolite includes a mesoporous zeolite having a framework type selected from FER, MEL, MFI, STT, and mixtures or symbionts thereof.

[0106] In certain embodiments, the zeolite of the disclosed catalyst composition includes large pore zeolite. Large pore zeolite contains channels limited by twelve-membered rings. Exemplary 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 symbionts thereof. For example, in certain embodiments, the zeolite comprises a large pore zeolite having a framework type selected from *BEA, FAU, MOR, and mixtures or intergrowths thereof.

[0107] As mentioned herein above, the disclosed catalyst composition generally includes a metal-promoted molecular sieve (e.g., zeolite). As used herein, "promoted" refers to a molecular sieve including one or more components intentionally added, as opposed to impurities that may be inherent in the molecular sieve. Therefore, compared to a catalyst without an intentionally added promoter, a promoter is a component intentionally added to enhance the activity of the catalyst. In one or more embodiments, in order to promote the SCR of nitrogen oxides, a suitable metal is exchanged into the molecular sieve. Copper participates in the conversion of nitrogen oxides and can therefore be a metal that can be used for exchange. Therefore, in some embodiments, a catalyst composition is provided, the catalyst composition including a copper-promoted molecular sieve (e.g., zeolite), such as Cu-CHA. In other embodiments, a catalyst composition is provided, the catalyst composition including an iron-promoted molecular sieve (e.g., zeolite), such as Fe-CHA. However, the present disclosure is not intended to be limited thereto, and catalyst compositions including other metal-promoted molecular sieves are also covered herein.

[0108] The promoter metal can generally be selected from the group consisting of: alkali metals, alkaline earth metals, transition metals of groups IIIB, IVB, VB, VIB, VIIB, VIIIB, IB and IIB; Group IIIA elements; Group IVA elements; lanthanides; actinides; and combinations thereof. In various embodiments, specific promoter metals that can be used to prepare metal-promoted molecular sieves include, but are not limited to, copper (Cu), cobalt (Co), nickel (Ni), lanthanum (La), manganese (Mn), iron (Fe), vanadium (V), silver (Ag), cerium (Ce), neodymium (Nd), praseodymium (Pr), titanium (Ti), chromium (Cr), zinc (Zn), tin (Sn), niobium (Nb), molybdenum (Mo), hafnium (Hf), yttrium (Y), tungsten (W) and combinations thereof. Such metals, such as combinations of copper and iron, can be used to obtain mixed Cu-Fe promoted molecular sieves, such as Cu-Fe-CHA. In certain embodiments, promoter metals associated with the disclosed zeolite components include copper (e.g., as CuO), iron (e.g., as Fe 2 O 3 ) or manganese (e.g., as MnO 2 ).

[0109] In one or more embodiments, the promoter metal content of the metal-promoted molecular sieve calculated as an oxide is at least about 0.1 wt.%, based on the total weight of the calcined molecular sieve (including the promoter), and is reported on a volatile-free basis. In some embodiments, the promoter metal of the zeolite component includes Cu, and the Cu content calculated as CuO is in the range of about 0.1 wt.% to about 20 wt.%, such as about 0.5 wt.% to about 17 wt.%, about 2 wt.% to about 15 wt.%, and about 2 wt.% to about 10 wt.%, in each case based on the total weight of the calcined molecular sieve, reported on a volatile-free basis. In other embodiments, the promoter metal of the zeolite component includes Fe, and the Fe content calculated as FeO is in the range of about 0.1 wt.% to about 20 wt.%, such as about 0.5 wt.% to about 17 wt.%, about 2 wt.% to about 15 wt.%, and about 2 wt.% to about 10 wt.%, in each case based on the total weight of the calcined molecular sieve, reported on a volatile-free basis. In some embodiments, the zeolite component (including the promoter metal) can be defined by the promoter metal to aluminum ratio within the promoter zeolite. For example, in some embodiments, the promoter metal to aluminum molar ratio is about 0.1 to about 0.5 (e.g., the Cu / Al ratio is about 0.1 to about 0.5).

[0110] In some embodiments, the SCR catalyst composition includes one or more components containing vanadium. Such compositions are referred to herein as "vanadium oxide-based compositions". In such embodiments, the vanadium can be in various forms, for example, including but not limited to free vanadium, vanadium ions, or vanadium oxides (vanadium oxide / vanadia), such as vanadium pentoxide (V pentoxide). 2 O 5 ). As used herein, "vanadium oxide (vanadia / vanadium oxide)" is intended to include any oxide of vanadium, such as vanadium pentoxide. In certain embodiments, compositions based on vanadium oxide include mixed oxides comprising vanadium oxide. The amount of vanadium oxide in the mixed oxide can vary, and in some embodiments, based on the gross weight of the mixed oxide, in the range of about 1 wt % to about 10 wt %. For example, the amount of vanadium oxide can be at least 1 wt %, at least 2 wt %, at least 3 wt %, at least 4 wt %, at least 5 wt % or at least 6 wt %, wherein the upper limit is about 10 wt % or not more than 10 wt %, not more than 9 wt %, not more than 8 wt %, not more than 7 wt %, not more than 6 wt %, not more than 5 wt % or not more than 4 wt %, and the lower limit is about 1 wt %.

[0111] Certain useful SCR catalyst compositions including vanadium supported on refractory metal oxides such as alumina, silica, zirconia, titania, ceria, and combinations thereof are described in U.S. Pat. No. 4,010,238 to Shiraishi et al. and U.S. Pat. No. 4,085,193 to Nakajima et al. and U.S. Publication No. 2017 / 0341026 to Chen et al., which are incorporated herein by reference in their entirety. In some embodiments, the upstream SCR catalyst composition includes a vanadium oxide / titania (V 2 O 5 / TiO 2 ), for example in the form of titanium dioxide with vanadium oxide dispersed thereon. The vanadium oxide / titanium dioxide may optionally be tungsten (e.g., WO 3 ) is activated or stabilized to obtain, for example, a V 2 O 5 and WO 3 V in the form of titanium dioxide 2 O 5 / TiO 2 / WO 3. It should be noted that in some embodiments, the vanadium oxide is not truly in the form of a mixed metal oxide; instead, the metal oxide components (e.g., titanium dioxide and vanadium oxide) may be present as discrete particles. In such embodiments, the amount of tungsten may vary and may be, for example, in the range of about 0.5 wt % to about 10 wt % based on the total weight of the mixed oxide. For example, the amount of tungsten may be at least 0.5 wt %, at least 1 wt %, at least 2 wt %, at least 3 wt %, at least 4 wt %, at least 5 wt %, or at least 6 wt %, with an upper limit of about 10 wt % or not more than 10 wt %, not more than 9 wt %, not more than 8 wt %, not more than 7 wt %, not more than 6 wt %, not more than 5 wt %, or not more than 4 wt %, and a lower limit of about 0.5 wt %.

[0112] Exemplary vanadium oxide-based SCR catalyst compositions may include components including, but not limited to, V 2 O 5 / TiO 2 、V 2 O 5 / WO 3 / TiO 2 、V 2 O 5 / WO 3 / TiO 2 / SiO 2 or a combination thereof. Additional vanadium oxide-based SCR catalyst compositions are described, for example, in U.S. Pat. Nos. 4,782,039 to Lindsey; 8,465,713 to Schermanz et al.; and 8,975,206 to Schermanz et al., each of which is incorporated herein by reference in its entirety.

[0113] Certain vanadium oxide-based SCR catalyst compositions may include other active components (e.g., other metal oxides). For example, in some embodiments, vanadium oxide-based SCR compositions suitable for use in the disclosed systems include vanadium oxide and antimony. In certain embodiments, such vanadium oxide-based SCR compositions include vanadium oxide and antimony that may be supported on a refractory metal oxide (e.g., TiO 2 、SiO 2 , WO 3 、Al 2 O 3, ZrO2, or a combination thereof) containing a composite oxide of vanadium and antimony. Exemplary vanadium oxide-based SCR compositions containing vanadium oxide and antimony are disclosed in U.S. Pat. No. 4,221,768 to Inoue et al.; and U.S. Publication No. 2018 / 0304236 to Zhao et al. and U.S. Publication No. 2019 / 0344247 to Zhao et al., all of which are incorporated herein by reference in their entirety.

[0114] Various additional SCR catalyst compositions are also disclosed, for example, in U.S. Pat. Nos. 7,998,423 to Boorse et al.; 9,017,626 to Tang et al.; 9,242,238 to Mohanan et al.; and 9,352,307 to Stiebels et al., which are incorporated herein by reference. The amount of SCR catalyst used on the substrate may vary, but may be about 1-10 g / in 3 , such as 1-7g / in 3 or 2-5.5g / in 3 The amount of loading.

[0115] According to the present disclosure, SCR catalyst compositions are generally prepared by providing metal-promoted molecular sieve materials. Molecular sieves having a CHA structure can be prepared according to various techniques known in the art, such as U.S. Patent Nos. 4,544,538 to Zones and 6,709,644 to Zones and U.S. Patent No. 8,883,119 to Bull et al., which are incorporated herein by reference in their entirety. Methods for preparing other types of molecular sieves are known in the art and can be readily used to provide the desired zeolite framework included in the disclosed composition.

[0116] To prepare metal-promoted molecular sieves according to various embodiments, metals (e.g., copper) are ion-exchanged into the molecular sieve. Such metals may be ion-exchanged into alkali metals or NH 4 molecular sieve (which can be obtained by converting NH 4 + Prepared by ion exchange into alkali metal molecular sieves, for example as disclosed in Bleken, F. et al. Topics in Catalysis 2009, 52, 218-228, which is incorporated herein by reference).

[0117] The preparation of metal-promoted molecular sieves may include an ion exchange process of a molecular sieve in particulate form with a metal precursor solution. For example, copper salts may be used to provide copper. In some embodiments, when copper acetate is used to provide copper, the copper concentration of the liquid copper solution used in the copper ion exchange is in the range of about 0.01 mole to about 0.4 mole, for example, in the range of about 0.05 mole to about 0.3 mole, in the range of about 0.1 mole to about 0.25 mole, in the range of about 0.125 mole to about 0.25 mole, in the range of about 0.15 mole to about 0.225 mole, and is approximately about 0.2 mole. In some embodiments, metals such as copper are ion exchanged to alkali metals or NH 4 + -chabazite to form Cu-chabazite.

[0118] 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 molecular sieves. In the case of including two or more metals in the molecular sieve material promoted by metal ions, multiple metal precursors (e.g., copper and iron precursors) can be ion exchanged simultaneously or separately in multiple exchange steps. In certain embodiments, the second metal can be exchanged into the molecular sieve material, which has first been promoted by the first metal (e.g., the second metal can be exchanged into the molecular sieve material promoted by copper). The second molecular sieve material can vary, and in some embodiments, can be a transition metal (e.g., iron or manganese) or an alkaline earth metal or an alkali metal.

[0119] In some embodiments, the SCR catalyst may be in the form of an integrated SCR / AMOx catalyst. Exemplary SCR / AMOx catalysts are described in, for example, U.S. Patent No. 8,524,185 to Caudle et al.; U.S. Patent No. 8,283,182 to Boorse et al.; and U.S. Patent No. 5,516,497 to Speronello et al., which are incorporated herein by reference. Suitable SCR / AMOx catalysts may be partitioned or layered so that the SCR catalyst and the AMOx catalyst are at least partially spaced apart. For example, in certain embodiments, an SCR / AMOx catalyst is provided, wherein the SCR catalyst is on a substrate having an inlet end and an outlet end, wherein the SCR catalyst is located at the inlet (upstream) end and the AMOx catalyst is located at the outlet (downstream) end. In other embodiments, the SCR / AMOx catalyst may include a bottom coating comprising an AMOx catalyst and a top coating having an SCR function. In some embodiments, the AMOx catalyst composition extends less than the full length of the SCR / AMOx catalyst, while the SCR catalyst composition extends the full length of the SCR / AMOx catalyst (e.g., as a top washcoat). These relative positions advantageously allow the AMOx catalyst to remove ammonia that is shed from the SCR catalyst.

[0120] Low temperature NO x Adsorbent (LT-NA)

[0121] The LT-NA components disclosed herein may include a molecular sieve containing a platinum group metal component. Such LT-NA components may effectively store NO at temperatures below 200°C. x , and releases the stored NO at higher temperatures x Any of the molecular sieves described herein can be used in the LT-NA component. In certain embodiments, the molecular sieve may include a framework type selected from CHA (chabazite), FER (ferrierite), AEI, and LEV (intercalated chabazite). The LT-NA component as disclosed herein may also include a metal organic framework (MOF). Such LT-NA components are effective in storing NO at temperatures below 200°C. x , and releases the stored NO at a temperature suitable for the downstream SCR catalyst x .

[0122] The molecular sieve of the LT-NA component may be impregnated with a platinum group metal component. As used herein, reference to impregnation with a platinum group metal component includes all forms of association of the platinum group metal component with the molecular sieve, such as where the platinum group metal component is in the ion exchange sites of the molecular sieve or other internal locations within the molecular sieve, or where the platinum group metal is present on the surface of the molecular sieve, or any combination of the above mentioned locations.

[0123] The term "platinum group metal component" refers to any component including a platinum group metal (e.g., Ru, Rh, Os, Ir, Pd, Pt). Reference to a "platinum group metal component" allows for the platinum group metal to exist in any valence state. For example, the platinum group metal may be in the form of a metal having a zero valence, or the platinum group metal may be in the form of an oxide. The terms "platinum (Pt) component," "rhodium (Rh) component," "palladium (Pd) component," "iridium (Ir) component," "ruthenium (Ru) component," and the like refer to corresponding platinum group metal compounds, complexes, and the like, which decompose or are otherwise converted to a catalytically active form, typically a metal or metal oxide, upon calcination or use of a catalyst. In some embodiments, the platinum group metal component is palladium as the sole platinum group metal component, but mixtures of platinum group metal components may also be used.

[0124] The concentration of the platinum group metal component can vary, but relative to the total dry weight of the molecular sieve, will be, for example, about 0.01wt.% to about 6wt.%. Based on the total dry weight of the molecular sieve, for example, about 0.1 wt.%, about 0.2 wt.%, about 0.5 wt.%, about 0.7 wt.%, about 0.9 wt.% or about 1.0 wt.% to about 1.5 wt.%, about 2.0 wt.%, about 2.5 wt.%, about 3.0 wt.%, about 3.5 wt.%, about 4.0 wt.%, about 4.5 wt.%, about 5.0 wt.% or about 6 wt.% of the platinum group metal component can be present in the molecular sieve. The weight of the platinum group metal component is measured and reported as metal (e.g., the weight of palladium). The total dry weight of the molecular sieve includes any added / exchanged metal (i.e., palladium).

[0125] Alternatively, the amount of the platinum group metal component in the LT-NA composition can be expressed as weight per unit volume of the substrate. For example, in certain embodiments, the amount of the platinum group metal component in the LT-NA is about 10 g / ft 3 About 140g / ft 3 , such as about 40g / ft 3 About 100g / ft 3 (Based on the volume of the underlying substrate on which the catalyst is disposed).

[0126] Based on the volume of the substrate, the LT-NA component is generally present in an amount of, for example, about 0.3 g / in 3 , about 0.4g / in 3 , about 0.5g / in 3 , about 0.6g / in 3 , about 0.7g / in 3 , about 0.8g / in 3 , about 0.9g / in 3 or about 1.0g / in 3 To about 1.5g / in 3 , about 2.0g / in 3, about 2.5g / in 3 , about 3.0g / in 3 , about 3.5g / in 3 , about 4.0g / in 3 , about 4.5g / in 3 , about 5.0g / in 3 or about 5.5g / in 3 The concentration is present on the substrate.

[0127] LT-NA components as disclosed herein can be easily prepared by methods well known in the art. In some embodiments, the disclosed LT-NA components can be prepared via an incipient wetness impregnation method. For example, a metal precursor (e.g., a platinum group metal component) can be dissolved in an aqueous or organic solution, and then the solution containing the metal is added to the material to be impregnated (e.g., a molecular sieve), and the material contains a pore volume substantially the same as the volume of the added solution. Capillary action draws the solution into the pores of the material. The added solution that exceeds the pore volume of the material causes the solution transport to change from a capillary action process to a much slower diffusion process. Subsequently, the impregnated material can be dried and optionally calcined to remove the volatile components in the solution, thereby depositing the metal on the surface of the material. The maximum load is limited by the solubility of the precursor in the solution. The concentration distribution of the impregnated material depends on the mass transfer conditions in the pores during impregnation and drying.

[0128] For example, a platinum group metal component precursor (such as palladium nitrate) can be loaded on the molecular sieve by impregnation, adsorption, ion exchange, incipient wetness, precipitation, etc. Non-limiting examples of suitable PGM precursors include palladium nitrate, tetraammine palladium nitrate, tetraammine platinum acetate, and platinum nitrate. Alternatively, a colloidal dispersion of a platinum group metal as discussed below can be used. During the calcination step, or at least during the initial stage of use of the catalyst, such compounds are converted into a catalytically active form of the metal or its compound.

[0129] Low temperature NH 3 Adsorbent (LT-AA)

[0130] The LT-AA components disclosed herein may include molecular sieves. Such LT-AA components are effective in storing NH at temperatures below 200°C. 3 , and releases the stored NH at higher temperatures when the SCR catalyst becomes functional 3. Any of the molecular sieves described herein can be used in the LT-AA component. In certain embodiments, the LT-AA component is a zeolite, which can be natural or synthetic, such as faujasite, chabazite, clinoptilolite, mordenite, silica, zeolite X, zeolite Y, ultrastable zeolite Y, ZSM-5 zeolite, potassium zeolite, or beta zeolite. Exemplary beta zeolites that can be used are disclosed in U.S. Pat. No. 6,171,556 to Burk et al., which is incorporated herein by reference in its entirety. When present, the LT-AA component is, for example, present at about 0.05 g / in 3 About 1g / in 3 The LT-AA components disclosed herein may also include a metal organic framework (MOF). Such LT-AA components are effective in storing ammonia at temperatures below 200°C and releasing the stored NO at temperatures suitable for downstream SCR catalysts. x In certain embodiments, the LT-AA component can be characterized as being substantially free of catalytic metals, such as platinum group metal components.

[0131] Low Temperature Water Vapor Adsorbent (LT-WA)

[0132] LT-WA components as disclosed herein may include a desiccant material that is thermally stable under typical operating conditions of an ammonia fueled engine. Such LT-WA components are effective in storing H at temperatures below 150°C. 2 O, and releases the stored H at higher temperatures 2 O. Any of the molecular sieves described herein may be used in the LT-WA component. Alternatively, silica, activated carbon, activated alumina, clay materials (e.g., montmorillonite), calcium sulfate, or calcium chloride may be used. When present, the LT-WA component may be used, for example, at about 0.05 g / in 3 About 3g / in 3 In certain embodiments, the LT-WA component may be characterized as being substantially free of catalytic metals, such as platinum group metal components. The LT-WA component as disclosed herein may also include a metal organic framework (MOF).

[0133] Oxidation Catalyst

[0134] The oxidation catalyst component of the emission treatment system may be a diesel oxidation catalyst (DOC) or an ammonia oxidation catalyst (AMOx).

[0135] The DOC is suitable, for example, for oxidizing the NO and / or CO and / or HC components of the exhaust gas. In the DOC, the unburned gaseous and non-volatile hydrocarbons and carbon monoxide are mostly burned to form carbon dioxide and water. In addition, part of the NOx component, NO, can be oxidized to NO 2. DOC catalysts are taught, for example, in U.S. Publication No. 2019 / 0015781 to Wei et al., which is incorporated herein by reference. The DOC can be formed in a single layer or multiple layers. Advantageously, a suitable DOC composition includes one or more platinum group metals impregnated on a porous refractory metal oxide support as disclosed herein. A suitable DOC composition may also include one or more non-PGM transition metals such as Mn or alkaline earth metals such as Ba impregnated on a porous refractory metal oxide support as disclosed herein. The DOC may be coated on a flow-through monolithic substrate or a wall-flow filter substrate as described herein. The DOC is typically located upstream of the SCR and may optionally be placed after a closely coupled SCR.

[0136] Advantageously, the DOC is in a tightly coupled position. The tightly coupled position is, for example, within about 12 inches (in) from the exhaust manifold (i.e., where the individual cylinder exhaust pipes are connected together). In some embodiments, the distance from the exhaust manifold to the upstream end of the DOC unit is about 0.5 inches to about 12 inches. In some embodiments, the distance is about 0.5in, about 1in, about 2in, about 3in, about 4in, about 5in, about 6in, about 7in, about 8in, about 9in, about 10in, about 11in or about 12in. In some embodiments, the distance is about 0.5in, about 1in, about 2in, about 3in, about 4in or about 5in to about 6in, to about 7in, to about 8in, to about 9in, to about 10in, to about 11in or to about 12in, wherein each combination of the lower endpoint and the upper endpoint clearly defines the scope of the embodiment of the present invention as expected.

[0137] Ammonia oxidation (AMOx) generally refers to the oxidation of NH 3 Reacts with oxygen to produce NO, NO 2 、N 2 O or N 2 The AMOx catalyst used in the present disclosure may include a platinum group metal component impregnated on a porous refractory metal oxide support. The AMOx catalyst may also include a hydrocarbon adsorbent, such as a zeolite (e.g., Fe-β zeolite) and / or a stabilizer or promoter (e.g., barium oxide). The AMOx catalyst is taught, for example, in U.S. Patent Application Publication No. 2011 / 0271664 to Boorse et al., which is incorporated herein by reference. The AMOx catalyst is typically located downstream of the SCR.

[0138] As used herein, "platinum group metal" refers to a platinum group metal or its oxide, including platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), osmium (Os), iridium (Ir), and mixtures thereof. In certain embodiments, the platinum group metal includes a combination of platinum and palladium, such as in a weight ratio of about 1:10 to about 10:1, such as equal to or greater than about 1.5:1, equal to or greater than about 2:1, or equal to or greater than about 5:1. The concentration of the platinum group metal component (e.g., Pt, Pd, or mixtures thereof) can vary, but will be, for example, about 0.1 wt.% to about 10 wt.% relative to the weight of the porous refractory oxide support material (e.g., about 1 wt.% to about 6 wt.% relative to the refractory oxide support). In certain embodiments, the platinum group metal may also include rhodium.

[0139] As used herein, "porous refractory metal oxide" refers to a porous metal oxide-containing material that exhibits chemical and physical stability at high temperatures, such as temperatures associated with diesel engine exhaust. Exemplary refractory oxides include alumina, silica, zirconia, titania, ceria, and combinations thereof. The combination may be in the form of a physical or chemical mixture. Exemplary refractory oxides include combinations of atomic doping, and include high surface area or activated compounds, such as activated alumina. Exemplary combinations of metal oxides include alumina-zirconia, ceria-zirconia, alumina-ceria-zirconia, lanthanum oxide-alumina, lanthanum oxide-zirconia-alumina, barium oxide-alumina, barium oxide lanthanum oxide-alumina, barium oxide lanthanum oxide-neodymium oxide alumina, and alumina-ceria. Exemplary alumina includes macroporous boehmite, γ-alumina, and δ / θ alumina. Available commercial alumina includes activated alumina, such as high bulk density γ-alumina, low bulk density or medium bulk density macroporous γ-alumina, or low bulk density macroporous boehmite and γ-alumina.

[0140] High surface area refractory metal oxide supports such as alumina support materials also known as "gamma alumina" or "activated alumina" can exhibit a surface area in excess of 60 m 2 / g, often up to about 200m 2 / g or more. Such activated alumina is usually a mixture of γ alumina phase and δ alumina phase, but may also contain a large amount of η alumina phase, κ alumina phase and θ alumina phase. "BET surface area" has its usual meaning and refers to the surface area used for N 2 Adsorption determines surface area using the Brunauer, Emmett, Teller method. Desirably, the activated alumina has a surface area of ​​60 m 2 / g to 350m 2 / g, such as 90m 2 / g to 250m 2 / g specific surface area.

[0141] The amount of platinum group metal may vary, but in certain embodiments, the amount of platinum group metal is about 10 g / ft 3 Up to 100g / ft 3 (based on the volume of the underlying substrate on which the catalyst is disposed), including, for example, at least about 40 g / ft 3 , at least about 45g / ft 3 , at least about 50g / ft 3 , at least about 55g / ft 3 , at least about 60g / ft 3 , at least about 65g / ft 3 , at least about 70g / ft 3 , at least about 75g / ft 3 or at least about 80g / ft 3 The concentration of a platinum group metal or any other composition on a substrate refers to the concentration per any three-dimensional section or area, such as any cross section of the substrate or the entire substrate, and is usually expressed as g / ft 3 or g / in 3 .

[0142] In some embodiments, the overall oxidation catalyst composition is present in an amount of, for example, about 0.3 g / in based on the volume of the substrate. 3 , about 0.4g / in 3 , about 0.5g / in 3 , about 0.6g / in 3 , about 0.7g / in 3 , about 0.8g / in 3 , about 0.9g / in 3 or about 1.0g / in 3 To about 1.5g / in 3 , about 1.7g / in 3 , about 1.8g / in 3 , about 1.9g / in 3 , about 2.0g / in 3 , about 2.1g / in 3 , about 2.2g / in 3 , about 2.3g / in 3 or about 2.5g / in 3 The concentration is present on the substrate.

[0143] The preparation of the refractory oxide material impregnated with a platinum group metal may include impregnating a refractory oxide support material in particulate form with a platinum group metal solution, such as one or more of a platinum solution and a palladium solution. A variety of platinum group metal components (e.g., platinum, palladium and / or rhodium) may be impregnated simultaneously or separately, and may be impregnated on the same support particles or separate support particles using an incipient wetness technique. The support particles may be sufficiently dry to adsorb substantially all of the solution to form a wet solid. An aqueous solution of a water-soluble compound or complex of a platinum group metal component may be utilized, such as palladium nitrate or platinum nitrate, tetraammine palladium nitrate or tetraammine platinum nitrate, or tetraammine palladium, or platinum acetate.

[0144] After treating the support particles with the platinum group metal solution, the particles are dried, such as by heat treating the particles at an elevated temperature (e.g., 100° C.-150° C.) for a period of time (e.g., 1 hour-3 hours), and then calcined to convert the platinum group metal component to a more catalytically active form. An exemplary calcination method involves heat treatment in air at a temperature of about 400° C.-550° C. for 1 hour-3 hours. The above method can be repeated as needed to achieve the desired level of platinum group metal impregnation. The resulting material can be stored as a dry powder or in slurry form.

[0145] Alternatively, the platinum group metal starting material may be in the form of a colloidal dispersion of platinum group metal nanoparticles rather than in the form of a solution. Such a colloidal suspension may be applied to a support in an incipient wetness technique as described above. Methods for impregnating a support with a colloidal platinum group metal material are described in U.S. Publication No. 2017 / 0304805 to Xu et al. and U.S. Publication No. 2019 / 0015781 to Wei et al., both of which are incorporated herein by reference in their entirety.

[0146] Base

[0147] The emission treatment component can be disposed on a substrate. Useful substrates can be 3-dimensional, having a length and diameter and volume similar to a cylinder. The shape does not necessarily have to conform to a cylinder. The length is the axial length defined by the inlet and outlet ends.

[0148] According to one or more embodiments, the substrate for the disclosed components can be composed of any material commonly used to prepare automotive catalysts, and can include a metal or ceramic honeycomb structure. The substrate provides a plurality of wall surfaces on which the washcoat composition is applied and adhered, thereby serving as a substrate for the catalyst composition. In some embodiments, the substrate includes a honeycomb substrate or a flow-through substrate in the form of a wall-flow filter.

[0149] 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-magnesium, zirconium silicate, sillimanite, magnesium silicate, zircon, petalite, α-alumina, aluminosilicates, etc.

[0150] The substrate may also be metallic, including 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 be in various shapes, such as pellets, corrugated sheets or monolithic foams. Examples of metal substrates include heat-resistant alkali metal alloys, especially those 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 account for at least about 15wt% (weight percentage) of the alloy based on the weight of the substrate in each case, for example, about 10wt% to about 25wt% of chromium, about 1wt% to about 8wt% of aluminum, and about 0wt% to about 20wt% of nickel. Examples of metal substrates include those with straight channels; those with protruding blades along the axial channel to interrupt gas flow and open the gas flow between channels; and those with blades and holes to enhance gas transmission between channels to allow radial gas transmission throughout the entire body. In certain embodiments, the metal substrate may be advantageously used in a close-coupled position, thereby allowing for rapid heating of the substrate and, accordingly, the catalyst composition coated therein.

[0151] Any suitable substrate for the articles disclosed herein may be employed, such as a monolithic substrate of the type having thin, parallel gas flow channels extending therethrough from the inlet or outlet face of the substrate so that the channels are open to fluid flow therethrough (a "flow-through substrate"). Another suitable substrate is of the type having a plurality of thin, generally parallel gas flow channels extending along the longitudinal axis of the substrate, wherein each channel may be blocked at one end of the substrate body, while alternating channels are blocked at the opposite end face (a "wall-flow filter"). Flow-through substrates and wall-flow substrates are also taught, for example, in U.S. Publication No. 2017 / 0333883 to Mohanan et al., which is incorporated herein by reference in its entirety.

[0152] Flow-through substrate

[0153] In some embodiments, the substrate is a flow-through substrate (e.g., a monolithic flow-through substrate, including a monolithic flow-through honeycomb substrate). The flow-through substrate has thin, parallel gas flow channels extending from the inlet end to the outlet end of the substrate so that the channels are open to fluid flow. The channels, which are substantially straight paths from their fluid inlet to their fluid outlet, are defined by walls on which a coating (e.g., 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 that can have 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.

[0154] For example, a flow-through substrate may have a width of about 50 in. 3 About 1200in 3 of volume, a pore density (entrance opening) of about 60 pores per square inch (cpsi) to about 500 cpsi or up to about 900 cpsi (e.g., about 200 cpsi to about 400 cpsi), and a wall thickness of about 50 microns to about 200 microns or about 400 microns.

[0155] Figure 1A and Figure 1B An exemplary substrate 2 is shown in the form of a flow-through substrate coated with a coating composition as 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 corresponding downstream end face 8 that is identical to the end face 6. The substrate 2 has a plurality of fine 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 to allow a fluid (e.g., airflow) to flow longitudinally through the substrate 2 via its flow channel 10. Figure 1B As can be more easily seen in FIG. 1 , the size and configuration of the wall 12 are such that the flow channel 10 has a generally regular polygonal shape. As shown, the coating composition can be applied in multiple, distinct layers, if desired. In the illustrated embodiment, the coating composition is comprised of both a discrete bottom layer 14 (e.g., LT-NA component) adhered to the wall 12 of the carrier member and a second discrete top layer 16 (e.g., LT-WA component) applied to the bottom layer 14. The present disclosure can be practiced with one or more (e.g., two, three, or four or more) layers of the composition and is not limited thereto. Figure 1B A two-layer embodiment is shown in FIG.

[0156] Wall Flow Filter Substrates

[0157] In some embodiments, the substrate is a wall-flow filter having a plurality of thin, substantially parallel airflow channels extending along the longitudinal axis of the substrate. Each channel may be blocked at one end of the substrate body, and the alternating channels are blocked at the opposite end faces. Such monolithic wall-flow filter substrates may contain up to about 900 or more flow channels (or "holes") per square inch of cross section, although much fewer flow channels may be used. For example, the substrate may have about 7 holes per square inch to 600 holes per square inch, more typically about 100 holes per square inch to 400 holes per square inch ("cpsi"). The hole may have a cross section of a rectangular, square, circular, elliptical, triangular, hexagonal or other polygonal shape.

[0158] Figure 2 1 shows a cross-sectional view of a monolithic wall-flow filter substrate portion, showing alternating blocked / clogged and open channels (pores). Blocked or clogged ends 100 alternate with open channels 101, wherein each opposing end is open and blocked, respectively. The filter has an inlet end 102 and an outlet end 103. Arrows through the porous wall 104 represent exhaust gas flow entering the open pore end, diffusing through the porous wall 104 and leaving the open outlet pore end. The blocked end 100 prevents gas flow and promotes diffusion through the pore wall. Each pore wall will have an inlet side 104a and an outlet side 104b. The channels are closed by the pore wall.

[0159] The wall flow filter article substrate may have a thickness of, for example, about 50 cm 3 , about 100cm 3 , about 200cm 3 、About 300cm 3 、Approx. 400cm 3 、About 500cm 3 、About 600cm 3 、About 700cm 3 、About 800cm 3 、About 900cm 3 or about 1000cm 3 To about 1500cm 3 , about 2000cm 3 、About 2500cm 3 、About 3000cm 3 、About 3500cm 3 、About 4000cm 3 、About 4500cm 3 or about 5000cm 3 The wall flow filter substrate may have 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.

[0160] The wall of the wall flow filter is porous and can have a wall porosity of at least about 50% or at least about 60% and an average pore size of at least about 5 microns before the functional coating is provided. For example, in some embodiments, the wall flow filter substrate will have a porosity of ≥50%, ≥60%, ≥65% or ≥70%. For example, before the catalytic coating is provided, the wall flow filter article substrate will have a wall porosity of about 50%, about 60%, about 65% or about 70% to about 75%, about 80% or about 85% and an average pore size of about 5 microns, about 10 microns, about 20 microns, about 30 microns, about 40 microns or about 50 microns to about 60 microns, about 70 microns, about 80 microns, about 90 microns or about 100 microns. The terms "wall porosity" and "substrate porosity" are interchangeable. Porosity is the ratio of the void volume divided by the total volume of the substrate. The pore size can be determined according to the ISO 15901-2 (static volume) procedure for nitrogen pore size analysis. Nitrogen pore size can be determined on a Micromeritics TRISTAR 3000 series instrument. Nitrogen pore size can be determined using the BJH (Barrett-Joyner-Halenda) calculation and 33 desorption points. Useful wall flow filters have high porosity, allowing high loading of the catalyst composition without excessive back pressure during operation.

[0161] coating

[0162] The composition as disclosed herein is applied to a substrate, such as a substrate mentioned herein. The coating may include one or more thin adhesive coating layers disposed on at least a portion of the substrate and adhered thereto. The coating may be on the substrate wall surface and / or in the holes of the substrate wall, i.e. "in the substrate wall" and / or "on the substrate wall". Therefore, the phrase "coating disposed on a substrate" means on any surface, for example on the wall surface and / or on the hole surface.

[0163] The compositions can be applied in the form of a washcoat. The washcoat is formed by preparing a slurry containing a specified solids content (e.g., about 10% by weight to about 60% by weight) in a liquid vehicle, which is then applied to the substrate and dried and calcined to provide a coating layer. If multiple coating layers are applied, the substrate can be dried and calcined after each layer is applied and / or after the desired number of layers are applied.

[0164] The washcoat slurry may optionally contain a binder (e.g., alumina, silica), a water-soluble or water-dispersible stabilizer, a promoter, an associative thickener, and / or a surfactant (including anionic, cationic, nonionic, or amphoteric surfactants). For example, the washcoat may include ZrO derived from a suitable precursor such as zirconyl acetate, zirconium acetate, or any other suitable zirconium precursor such as zirconyl nitrate and zirconium nitrate.2 Binders. Zirconium acetate binders provide coatings that remain uniform and intact after heat aging. Other potentially suitable binders include, but are not limited to, alumina and silica. Alumina binders include aluminum oxide, aluminum hydroxide, and aluminum oxyhydroxide. Many also use aluminum salts and colloidal forms of alumina. Silica binders include various forms of SiO 2 , including silicates and colloidal silica. The binder composition may include any combination of zirconium oxide, aluminum oxide and silica. When present, the binder may be used in an amount of about 1 wt% to 5 wt% of the total carrier coating load.

[0165] The pH of the slurry may range 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 ammonium hydroxide or aqueous nitric acid.

[0166] The slurry can be ground to enhance mixing of the particles and form a uniform material. Grinding can be done in a ball mill, a continuous mill or other similar equipment, and the solid content of the slurry can be, for example, about 20 wt% to 60 wt%, such as about 20 wt% to 40 wt%. In one embodiment, the slurry after grinding is characterized by a D90 particle size of about 10 microns to about 40 microns, such as about 10 microns to about 30 microns or about 10 microns to about 15 microns.

[0167] The slurry is then coated on a substrate using any washcoat technique known in the art. In one embodiment, the substrate is dipped into the slurry or otherwise coated with the slurry one or more times. Thereafter, the coated substrate is dried at an elevated temperature (e.g., 100° C.-150° C.) for a period of time (e.g., 10 minutes-3 hours) and then calcined by heating, for example, at 400° C.-600° C. for about 10 minutes to about 3 hours. After drying and calcining, the final washcoat coating layer can be considered to be substantially solvent-free.

[0168] The washcoat loading obtained by the washcoat techniques described above can be determined by calculating the difference in the coated and uncoated weights of the substrate after calcination. As will be apparent to one skilled in the art, the loading can be modified by altering the slurry rheology. Additionally, the washcoat-generating coating / drying / calcining process can be repeated as needed to build up the coating to the desired loading level or thickness, meaning that more than one washcoat may be applied.

[0169] A washcoat may be applied so that the various coating layers are in direct contact with the substrate. Alternatively, one or more "undercoats" may be present so that at least a portion of one or more catalytic or adsorbent coating layers is not in direct contact with the substrate (but is in contact with the undercoat). One or more "overcoats" may also be present so that at least a portion of one or more coating layers is not directly exposed to the gas stream or atmosphere (but is in contact with the overcoat).

[0170] Different coating layers may be in direct contact with each other. Alternatively, different coating layers may not be in direct contact. Various coating layers may be considered as primers, topcoats, or intermediate layers. Primers are layers "below" coating layers, topcoats are layers "above" coating layers, and intermediate layers are layers "between" two coating layers. Intermediate layers, primers, and topcoats may contain one or more functional compositions, or may not contain functional compositions.

[0171] Advantageously, various coatings can be "partitioned", including partition layers. This can also be described as "lateral partitioning". For example, a layer can extend from the inlet end toward the outlet end, extending 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 toward the inlet end, extending 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 middle zone can, for example, extend 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.

[0172] Method for treating an exhaust gas stream

[0173] In another aspect, a method for treating a gaseous exhaust stream, such as to reduce NOx, is provided, the gaseous exhaust stream comprising nitrogen oxides (NO x ) mixture. In some embodiments, such methods can not only effectively reduce the NO associated with such engines x The method can effectively adsorb certain gaseous components of the exhaust gas stream emitted by such an engine to enhance the effectiveness of the system. For example, the method includes contacting the gaseous exhaust gas stream with an SCR catalyst and one or more adsorption components located upstream of the SCR catalyst, the adsorption components being selected from the group consisting of: low temperature NO xadsorbents (LT-NA), low temperature ammonia adsorbents (LT-AA), low temperature water vapor adsorbents (LT-WA), and combinations thereof. The method may also include treating the exhaust gas stream with one or more oxidation catalysts, such as an AMOx catalyst, typically located downstream of the SCR catalyst.

[0174] In some embodiments, the LT-NA component is effective in releasing NO and NO at temperatures above about 300°C. 2 In some embodiments, the LT-NA component is effective in releasing NO and NO at a temperature greater than about 325°C. 2 One or both of .

[0175] The compositions, components, systems and methods of the present invention are suitable for treating exhaust streams from mobile emission sources such as trucks and cars. The compositions, components, systems and methods of the present invention are also suitable for treating exhaust streams from stationary sources such as power plants.

[0176] It will be readily apparent to those skilled in the art that suitable modifications and changes may be made to the compositions, components, systems and methods described herein without departing from the scope of any embodiment or aspect thereof. The compositions, components, systems and methods provided are exemplary and are not intended to limit the scope of the embodiments protected by the claims. All various embodiments, aspects and options disclosed herein may be combined in all variations. The scope of the compositions, components, systems and methods 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 described, unless other specific incorporation statements are specifically provided. Example

[0177] The following examples are intended to be illustrative, and are not intended to limit the scope of the present disclosure in any way.

[0178] Example 1: DOC product

[0179] An undercoat catalyst slurry containing ground alumina powder impregnated with Pd (0.5 wt.%), Ba (0.8 wt.%) and Pt (0.3 wt.%) was prepared and adjusted to pH 4.5 to 5.0 with nitric acid. The undercoat slurry had a solid content of 38 wt.%. A topcoat slurry containing alumina, Mn (5 wt.%) and Pt-amine (3.3 wt.%) was prepared, ground and adjusted to pH 4.5 to 5.0 with nitric acid. The topcoat slurry had a solid concentration of 37 wt.%. Zeolite beta (0.35 g / in 3 ) is added to the top coating slurry.

[0180] The basecoat slurry was applied to a 1" x 3" 400 cpsi (cells per square inch) honeycomb substrate of full core length via a washcoat technique. The coated substrate was air dried at 120°C and calcined at 500°C for 1 hour to give a 1.6 g / in 3 The top coating slurry was applied over the entire base coating, dried and calcined as a base coating to obtain a coating load of 2.5 g / in 3 The total coating loading was 200 ng / ml and the Pt / Pd weight ratio was 3 / 1.

[0181] Example 2 :LT-NA-DOC product (DOC with NOx adsorbent, regional design)

[0182] The product includes a partition design, wherein the 3 A 1" x 3" 400 cpsi (pores per square inch) honeycomb substrate with a PGM (platinum group metal) loading of 100% and a Pt / Pd weight ratio of 0 / 1 was coated over the entire core length as a NOx adsorbent (LT-NA). The back half of the substrate was coated with a DOC topcoat containing a mixture of 5 wt.% Mn on an alumina support and 5 wt.% Si on an alumina support (1.4 g / in 3 ) and HC-trap molecular sieve 2wt.%Fe / β(0.7g / in 3 ), the mixture was impregnated with Pt and Pd (Pt / Pd weight ratio was 9 / 1, and PGM loading was 80 g / ft 3 ). The total PGM loading of this LT-NA-DOC is 160g / ft 3 , and the Pt / Pd distribution is 36 / 124.

[0183] Example 3 :LT-NA-DOC product (DOC containing NOx adsorbent, layered design)

[0184] The article comprises a layered design different from Example 2, wherein a 1" x 3" 400 cpsi (cells per square inch) honeycomb substrate is coated over the entire core length with a LT-NA-DOC article acting as a NOx adsorbent (LT-NA), the LT-NA-DOC article consisting of a Pd / Ferrierite (FER) undercoat with a PGM loading of 80 g / ft 3 The DOC top coating is a mixture of 5 wt.% Mn on alumina support and 5 wt.% Si on alumina support (1.4 g / in 3 ) impregnated with Pt and Pd (Pt / Pd weight ratio is 9 / 1 and PGM loading is 60 g / ft 3). The total PGM loading of this LT-NA-DOC is 140g / ft 3 , and the Pt / Pd distribution is 54 / 86.

[0185] Example 4: Selective Catalytic Reduction on Filter (SCRoF) Article

[0186] A catalyst slurry containing ground Cu / CHA (3.3 wt.% Cu) and 5 wt.% zirconium acetate binder was prepared and applied via washcoat technology to a 300 / 12, 1" diameter x 5.5" length honeycomb substrate filter having a volume of 70.8 cm 3 The coated core was dried at 130°C and calcined at 550°C for 1 hour to obtain 1.75 g / in 3 coating load.

[0187] Example 5: Pollutant Reduction

[0188] The coated DOC article of Example 1 was hydrothermally aged in a tube furnace at 800°C for 16 hours with a feed gas composition of 10% H 2 O, 10% O 2 and margin N 2 The coated LT-NA-DOC articles of Example 2 and Example 3 were hydrothermally aged at 800°C for 16 hours and 750°C for 25 hours in a tube furnace, respectively, wherein the feed gas composition was 10% H 2 O, 10% O 2 and margin N 2 The SCR products were also hydrothermally aged in a tube furnace at 750 °C for 16 h, with the feed gas composition being 10% H 2 O, 10% O 2 and margin N 2 The samples were evaluated in a lab reactor as a DOC+SCR or LT-NA-DOC+SCR system, where the SCR article was installed downstream of the DOC or LT-NA-DOC article. The lab reactor was equipped to simulate the Worldwide Harmonized Light-Duty Vehicles Test Cycle (WLTC), where engine output emissions of THC, CO and NO can be recreated with dynamic temperature and flow traces on a 1 Hz basis. x NH 3 / NO x Ratio = 1 injection NH 3 Two sampling lines were installed in the laboratory reactor to measure the proposed 3Effectiveness of Exhaust Treatment System for Fuel Scenario. Take one sampling line between the DOC or LT-NA-DOC article and the SCR article, and a second sampling line after the combined system.

[0189] Three experiments were conducted to measure the proposed 3 The effectiveness of exhaust treatment systems in fuel vehicles.

[0190] Experiment 1. A baseline was established using conventional diesel vehicle emissions using an emissions treatment system consisting of the DOC articles of Example 1 and Example 2, either alone or in combination with the SCR article of Example 4.

[0191] Experiment 2. Using a catalyst system consisting of the DOC or LT-NA-DOC articles of Examples 1 and 3 alone or in combination with the SCR article of Example 4 to treat an exhaust gas feed containing no HC / CO / NO 2 / CO 2 Simulated NH 3 Fuel vehicle emissions. Assuming NH 3 The fuel has the same combustion efficiency as diesel.

[0192] Experiment 3: Using the catalyst system of Experiment 2 to treat a high amount of NO in the exhaust gas x Simulated NH 3 Fuel vehicle emissions. Using additional NH in the cylinder 3 fuel to produce the same heating efficiency as diesel because, on a volume basis, NH 3 The calorific value is lower.

[0193] To provide an understanding of the experiments, reference is made to the accompanying drawings in which the disclosure described herein is illustrated by way of example and not limitation.

[0194] Figure 4 Plotted are temperature traces at the DOC inlet, after the DOC, and before the SCR, and space velocity (SV) traces for various simulated vehicle exhausts (including the diesel exhaust of Experiment 1) for a system comprising a combination of the DOC article of Example 1 and the SCR article of Example 4. The average of three replicates is plotted.

[0195] Figure 5 Depicts the inlet NO of an experiment for an exhaust gas treatment system including a combination of the DOC article of Example 1 and the SCR article of Example 4. x Curves depict the average of three replicates.

[0196] Figure 6Depicted are NO emissions according to the WLTC protocol for three experiments of exhaust gas treatment systems including the DOC article of Example 1 alone or in combination with the SCR article of Example 4. x Conversion performance. Inlet NO x The curves correspond to 0.98 g and 1.26 g NO for Experiments 1 and 2 and 3, respectively. x Engine output emissions.

[0197] CO, HC and NO of DOC products only x The results for % conversion are set forth in Table 2 below.

[0198] Table 2:

[0199]

[0200] The results for % conversion of CO, HC and NOx on the DOC+SCR exhaust treatment system are set forth in Table 3 below.

[0201] Table 3:

[0202]

[0203] The above results show that the DOC+SCR exhaust treatment system can control NH 3 Fuel vehicle applications for Euro7 applications.

[0204] Regarding Example 2 and Example 3, Figure 7 NOx conversion according to the WLTC protocol is depicted for three experiments, with the LT-NA-DOC article of Example 2 alone or in combination with the SCR article of Example 4 at the conditions of Experiment 1, and the LT-NA-DOC article of Example 3 alone or in combination with the SCR article of Example 4 at the conditions of Experiments 2 and 3. The inlet NOx curves correspond to 0.98 g and 1.26 g NOx engine output emissions for Experiments 1 and 2 and Experiment 3, respectively.

[0205] CO, HC and NO of only two LT-NA-DOC products x The results for % conversion are set forth in Table 4 below.

[0206] Table 4:

[0207]

[0208] The conversion % results for CO, HC and NOx for both LN-NA-DOC+SCR exhaust treatment systems are set forth in Table 5 below.

[0209] Table 5:

[0210]

[0211] The above results show that the LT-NA-DOC+SCR exhaust treatment system can control NH 3 Fuel vehicle applications for Euro7 applications.

[0212] Figure 8 Plotted are the cumulative NOx emissions according to the FTP cold start US06 protocol after the DOC+SCR systems of Examples 1 and 4 and after the LT-NA-DOC+SCR exhaust treatment systems of Examples 3 and 4 over the first 500 seconds of the FTP cycle.

[0213] Fig. 9 Depicted are NOx conversions according to the FTP cold start US06 protocol after the DOC+SCR systems of Examples 1 and 4 and after the LT-NA-DOC+SCR exhaust treatment systems of Examples 3 and 4 during the first 500 seconds of the FTP cycle.

[0214] Figure 8 and Fig. 9 The results show that the LT-NA-DOC+SCR exhaust treatment system can control NH 3 The fuel vehicle exhaust was used for Euro 7 applications and further demonstrated that the LT-NA-DOC article can improve the overall exhaust treatment system performance for reducing NOx.

[0215] Figure 8 and Fig. 9 The NOx conversion performance of the LT-NA-DOC+SCR system shown in Figure 2 shows that the use of the LT-NA-DOC product reduces cold start NOx emissions by more than 50% in the first 500 seconds of the FTP cycle ( Figure 8 In summary, the application of LT-NA-DOC products increased the NOx conversion rate of the entire exhaust treatment system by 6% (from 82% to 88%). Fig. 9 The results are shown in and reported in Table 6 below.

[0216] Table 6:

[0217]

[0218] Example 6: Selective Catalytic Reduction (Cu-CHA-SCR) Products

[0219] A catalyst slurry containing ground Cu-CHA (3.3 wt.% Cu) and 5 wt.% zirconium acetate binder was prepared and applied via a washcoat technique to a 64.4 cm3 A 400 cpsi, 1" diameter x 5" length honeycomb flow-through substrate was prepared. The coated core was dried at 130°C and calcined at 550°C for 1 hour to give a 2.85 g / in 3 coating load.

[0220] Example 7: Selective Catalytic Reduction (Fe-CHA-SCR) Products

[0221] A catalyst slurry containing ground Fe-CHA (2.5 wt.% Fe) and 5 wt.% zirconium acetate binder was prepared and applied via a washcoat technique to a 19.3 cm 3 A 600 cpsi, 1" diameter x 1.5" length flow-through honeycomb substrate was prepared. The coated core was dried at 130°C and calcined at 550°C for 1 hour to obtain a 2.85 g / in 3 coating load.

[0222] Example 8: Ammonia oxidation catalyst preparation

[0223] In volume 12.9cm 3 AMOx catalyst products with a layered design were prepared on a flow-through honeycomb substrate. First, a silica-alumina (0.5 g / in 3 ) on Pt(2g / ft 3 ) bottom layer and applied it to the full length substrate via a carrier coating technique. 3 A top layer of Cu-CHA (CuO loading 5.1 wt%) loaded and containing 5 wt.% zirconium acetate binder was applied to the coated support via washcoat technique. The coated cores were dried and calcined at 450°C for 1 hour.

[0224] Example 9: Pollutant Reduction

[0225] The Cu-CHA SCR product of Example 6 was hydrothermally aged in a tube furnace at 750°C for 16 hours, wherein the feed gas composition was 10% H 2 O, 10% O 2 , Residue N 2 The Fe-CHA SCR products and AMOx products of Examples 7 and 8 were hydrothermally aged in a tube furnace at 650°C for 100 h, wherein the feed gas composition was 10% H 2 O, 10% O 2 and margin N 2 The SCR products were also hydrothermally aged in a tube furnace at 750 °C for 16 h, with the feed gas composition being 10% H 2 O, 10% O 2 and margin N 2The samples were evaluated in a laboratory reactor as a Cu-CHA SCR+AMOx or Fe-CHA SCR+Cu-CHA SCR+AMOx system. The laboratory reactor was equipped to simulate the dynamic temperature, flow and engine output emission conditions of the WLTC (Worldwide Harmonized Light Duty Vehicles Test Cycle) on a second-by-second basis. The WLTC driving cycle represents 23 km of driving at various speeds and loading conditions. A sampling line was installed in the laboratory reactor to measure the proposed NH 3 The effectiveness of the exhaust treatment system for the fuel scenario. The engine output NOx curve for the current example corresponds to 18.8g engine output NOx. Unless otherwise stated, the exhaust gas was treated with 1.05 NH 3 / NO X Than injecting ammonia.

[0226] Experiment 4. Establishing a baseline using Cu-CHA SCR+AMOx (System 1).

[0227] Experiment 5. The ammonia dosage of system 1 was adjusted to 1.25 NH 3 / NOx ratio, lasting from 1140s to 1260s and from 1500s to 1740s.

[0228] Experiment 6. (i) Ammonia dosage of system 1 was adjusted to 1.25 NH 3 / NOx ratio, for 1140 seconds-1260 seconds and 1500 seconds-1740 seconds, and (ii) when NOx emissions are 0, the air to fuel ratio (λ) is adjusted to 1.00, and when NOx emissions>0, the air to fuel ratio (λ) is adjusted to 1.05 between 0 seconds-600 seconds.

[0229] Experiment 7. Establishing a baseline using Fe-CHA SCR + Cu-CHA SCR + AMOx (System 2).

[0230] Experiment 8. (i) Ammonia dosage of system 2 was adjusted to 1.25 NH 3 / NOx ratio for 1140 seconds-1260 seconds and 1500 seconds-1740 seconds, and (ii) when NOx emissions are 0, the air to fuel ratio (λ) is adjusted to 1.00, or when NOx emissions>0, the air to fuel ratio (λ) is adjusted to 1.05, for the entire WLTC cycle.

[0231] To provide an understanding of the experiments, reference is made to the accompanying drawings in which the disclosure described herein is illustrated by way of example and not limitation.

[0232] Fig.10Plotted are temperature traces of inlet temperature, outlet temperature and space velocity (SV) of the WLTC cycle of vehicle exhaust simulating the systems of Experiments 4 to 8. The average of three replicates is plotted.

[0233] Fig.11 The overall NOx conversion is depicted for Experiments 4 to 8. In all cases, the overall NOx conversion meets or exceeds the current Euro7 NOx emission regulations of 0.09 mg / km.

[0234] Fig.12 The inlet NO in the range of 1140 s to 1800 s for Experiments 4 and 7 is plotted. x and outlet NOx curve. Fig.13 Inlet NOx and outlet NOx curves in the range of 1140 seconds to 1800 seconds are plotted for Experiment 4 and Experiment 5. The average of three replicates is plotted.

[0235] Fig.12 and Fig.13 The NOx emission curves shown in FIG. 1 show improved high temperature NOx conversion and reduced undesirable NOx. 2 Benefit of adding Fe-CHA SCR to the system (Experiment 4 vs. Experiment 7) on O emissions (not shown). Fig.12 and Fig.13 It also revealed that the increase in NH in the 1140-1260 seconds and 1500-1740 seconds segments of the driving cycle 3 benefit of the amount given (experiment 4 vs. experiment 5); because it causes an improvement in NOx conversion. These results show that NH 3 NOx emissions from fuel engines can be controlled using smart NH 3 Strategies such as adjusting ANR based on vehicle speed, load and exhaust temperature can be used to further mitigate this.

[0236] Fig.14 Cumulative NOx emissions for Experiments 7 and 8 are depicted, with the inset depicting an air-to-fuel ratio (λ) with a plot cutoff of 2.00. As observed, adjusting the air-to-fuel ratio (λ) from >20 typically observed in diesel applications to 1.00 or 1.05 typically observed in gasoline applications, based on the presence or absence of NOx, did not show a significant effect on NOx conversion efficiency or NOx emissions, indicating that the application of such technology can cover air-to-fuel ratios typical for gasoline or diesel engine operation.

Claims

1. An emission treatment system for reducing NO in an exhaust stream of an ammonia fueled engine x , the emission treatment system comprises: a selective catalytic reduction (SCR) catalyst disposed on a substrate in fluid communication with the exhaust stream of the ammonia fueled engine; as well as An oxidation catalyst is disposed on a substrate upstream and / or downstream of the SCR catalyst and in fluid communication with the exhaust gas flow and the SCR catalyst.

2. The emissions treatment system of claim 1, wherein the oxidation catalyst comprises a refractory metal oxide support impregnated with a platinum group metal (PGM).

3. The emission treatment system of claim 2, wherein the PGM comprises platinum, palladium, rhodium, or a combination thereof.

4. The emission treatment system of any one of claims 2 to 3, wherein the oxidation catalyst further comprises a refractory metal oxide support impregnated with a non-PGM transition metal, an alkaline earth metal, or a combination thereof.

5. The emission treatment system of claim 4, wherein the non-PGM transition metal comprises manganese.

6. The emission treatment system of any one of claims 4-5, wherein the alkaline earth metal comprises barium.

7. The emission treatment system of any one of claims 1 to 6, wherein each of the oxidation catalysts is selected from a diesel oxidation catalyst (DOC) and a selective ammonia oxidation catalyst (AMOx).

8. The emission treatment system of any one of claims 1 to 7, wherein the SCR catalyst comprises a metal-promoted molecular sieve, a vanadium oxide-based composition, or a combination thereof.

9. The emission treatment system of any one of claims 1 to 8, wherein the SCR catalyst is a copper-containing zeolite, an iron-containing zeolite, or a manganese-containing zeolite.

10. The emission treatment system of claim 9, wherein the zeolite has a framework type selected from LEV, CHA, AEI, MEI, FER, *BEA, FAU, or combinations thereof.

11. The emission treatment system of any one of claims 1 to 10, wherein the SCR catalyst and the oxidation catalyst are present in the form of a SCR / AMOx catalyst.

12. The emission treatment system according to any one of claims 1 to 11, further comprising one or more adsorption components, wherein the one or more adsorption components are selected from low temperature NO x adsorbent (LT-NA), low temperature ammonia adsorbent (LT-AA), low temperature water vapor adsorbent (LT-WA), or a combination thereof.

13. The emission treatment system of claim 12, wherein the one or more adsorbent components are arranged in any order and combination.

14. The emission treatment system of any one of claims 12-13, wherein each of the one or more adsorbed components is disposed on a substrate located upstream or downstream of the SCR catalyst and in fluid communication with the exhaust gas flow and the SCR catalyst.

15. The emission treatment system of any one of claims 12 to 14, wherein each of the one or more adsorbent components is disposed on the same substrate in a mixture, in a zoned configuration, or in a layered configuration.

16. The emission treatment system of any one of claims 12 to 15, wherein one or more of the SCR catalyst, the oxidation catalyst, and the one or more adsorption components are disposed on the same substrate in a mixture, in a zoned configuration, or in a layered configuration.

17. The emission treatment system of any one of claims 12 to 16, wherein the one or more adsorbent components and the DOC are disposed on the same substrate in a mixture, in a zoned configuration, or in a layered configuration.

18. The emission treatment system of any one of claims 1 to 17, further comprising one or more additional SCR catalysts, one or more additional oxidation catalysts, or a combination thereof.

19. The emission treatment system of claim 18, the emission treatment system comprising, in order, starting with the emission treatment component closest to the engine, one of the following arrangements: (a) Adsorption components, DOC, SCR catalyst and AMOx; (b) SCR, adsorption components, DOC and AMOx; (c) adsorption components, SCR catalyst, DOC, SCR catalyst and AMOx; (d) Adsorption components, SCR catalyst and AMOx; (e) Adsorption components, DOC and SCR catalyst; (f) SCR catalyst, AMOx and adsorption components; (g) SCR catalyst and AMOx; (h) DOC and SCR catalyst; or (i) SCR catalyst, SCR catalyst and AMOx.

20. The emission treatment system of any one of claims 12 to 19, wherein the LT-NA is present and comprises a molecular sieve or a metal organic framework (MOF) impregnated with at least one platinum group metal component.

21. The emission treatment system of any one of claims 12 to 20, wherein the LT-AA is present and comprises a molecular sieve or a MOF.

22. The emission treatment system of any one of claims 12 to 21, wherein the LT-WA is present and is selected from the group consisting of molecular sieves, clays, activated carbon, activated alumina, silica, calcium sulfate, calcium chloride, MOFs, and combinations thereof.

23. An emission treatment system according to any one of claims 12 to 22, wherein the SCR catalyst, one or more of the one or more adsorption components and the oxidation catalyst are disposed on a flow-through substrate in the form of a honeycomb, the substrate having a plurality of longitudinally extending airflow channels extending from an inlet to an outlet, and / or wherein the SCR catalyst, one or more of the one or more adsorption components and the oxidation catalyst are disposed on a wall-flow substrate or optionally on a metal substrate having flow-through channels, wherein a portion of the exhaust gas is fluidly connected between the channels.

24. A method for reducing NO in the exhaust gas stream of an ammonia fueled engine x A method comprising contacting the exhaust gas stream with an emissions treatment system according to any one of claims 1 to 23.

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