Oxidation catalyst composition, oxidation catalyst article, diesel oxidation catalyst article, catalyzed soot filter article, exhaust gas treatment system and method for treating an exhaust gas stream.

Abstract

OXIDATION CATALYST COMPOSITION, OXIDATION CATALYST ARTICLE, CATALYZED SOOT FILTER ARTICLE, EXHAUST GAS TREATMENT SYSTEM, AND METHOD FOR TREATING AN EXHAUST GAS STREAM. This is an oxidation catalyst composition, wherein the composition includes a plurality of platinum group metal particles having a multimodal particle size distribution. The plurality of platinum group metal particles includes a first population of platinum group metal particles with a particle size range from about 0.5 nm to about 3 nm and a second population of platinum group metal particles with a particle size range from about 4 nm to about 15 nm. Methods for the preparation and use of the catalyst composition are also provided, as well as catalyst articles and exhaust gas treatment systems employing such catalyst articles.The catalyst requires enhanced stability in terms of oxidation performance after undergoing degreening and / or aging, compared to conventional oxidation catalysts, in particular less loss of NOx oxidation performance.

Description

1 / 72 “OXIDATION CATALYST COMPOSITION, OXIDATION CATALYST ARTICLE, DIESEL OXIDATION CATALYST ARTICLE, CATALYZED SOOT FILTER ARTICLE, EXHAUST GAS TREATMENT SYSTEM AND METHOD FOR TREATING AN EXHAUST GAS STREAM” Field of Invention

[0001] This disclosure relates generally to the field of exhaust gas treatment catalysts, particularly oxidation catalyst compositions comprising platinum group metal particles, methods for the preparation and use of such catalyst compositions, and catalyst articles and exhaust gas treatment systems employing such catalyst compositions. Background of the Invention

[0002] Environmental regulations for emissions from internal combustion engines are becoming increasingly stringent worldwide. Lean-burning diesel engines provide the user with excellent fuel economy due to their operation at high air / fuel ratios under lean fuel conditions. However, diesel engines also emit exhaust gas emissions containing particulate matter, unburned hydrocarbons, carbon monoxide (CO), and nitrogen oxides (NOx), where NOx describes various chemical species of nitrogen oxides, including nitrogen oxide (NO) and nitrogen dioxide (NO2), among others. The two main components of exhaust particulate matter are the soluble organic fraction and the soot fraction. The soluble organic fraction condenses into layers of soot and is generally derived from unburned diesel oil and lubricating oils.The soluble organic fraction can exist in diesel exhaust as a vapor or as an aerosol (i.e., fine droplets of liquid condensate), depending on the exhaust gas temperature. Soot is... Petition 870260065670, dated 03 / 07 / 2026, page 10 / 92 2 / 72 predominantly composed of carbon particles.

[0003] Oxidation catalysts comprising precious metals, such as platinum group metals, dispersed in a refractory metal oxide support, are known for use in the treatment of diesel engine exhaust gases in order to convert gaseous pollutants of CO and hydrocarbons by catalyzing the oxidation of these pollutants into carbon dioxide (CO2) and water. These catalysts may be contained in diesel oxidation catalysts, which are placed in the exhaust flow path of a diesel engine to treat the exhaust gas stream. Typically, diesel oxidation catalysts are prepared on ceramic or metallic carrier substrates onto which one or more catalyst coating compositions are deposited.

[0004] Diesel soot removal is achieved through active or passive regeneration of a soot filter. Active regeneration can be performed by injecting additional diesel fuel into the inlet of diesel oxidation catalysts, and the exothermic reaction released by the combustion of the fuel significantly increases the temperature in a downstream catalyzed soot filter and initiates the combustion of soot by O2 according to the equation (C+O2 ^CO / CO2). This reaction typically has temperatures exceeding 600 °C. Passive soot regeneration uses NO2 instead of O2 to oxidize soot according to the equation (C+NO2 >CO / CO2 +NO). This reaction is efficient at temperatures above 300 °C and can often be performed during normal driving without the need for fuel injection, resulting in a penalty in fuel economy.

[0005] In addition to the conversion of gaseous hydrocarbons, CO, and the soluble organic fraction of particulate matter, oxidation catalysts containing platinum promote the oxidation of NO to NO2. Platinum (Pt) remains the most effective platinum group metal for oxidizing NO to NO2. The metals of Petition 870260065670, dated 03 / 07 / 2026, page 11 / 92 Platinum group metals (3 / 72) can be incorporated into diesel oxidation catalyst compositions in various forms. For example, certain catalyst compositions incorporate platinum group metals in the form of particles (e.g., nanoparticles). See Paulus et al., J. Electroanal. Chem., 134, 495 (2001); Yoo et al., J. Catalysis, 214, 1-7 (2003); and Jain et al., Acc. Chem. Res., 41, 1578-1586 (2008). For example, Pt nanoparticles with controlled size and shape offer great opportunities for the development of high-performance industrial Pt catalysts. See Zhao et al., Adv. Mater., 11, 217-220 (1999); Oishi et al., React. Funct. Polym. 67, 662 to 668 (2007); and Peng et al., Nano Lett., 9, 3704–3709 (2009).When platinum group metals are incorporated into a catalyst composition in the form of particles (e.g., nanoparticles), elevated temperature particle growth (i.e., sintering), leading to a decrease in surface area, is a primary deactivation route for the catalyst composition. In particular, NO oxidation has been widely reported to be structure-sensitive in Pt; that is, the rotation frequency (TOF) is strongly dependent on the Pt particle size (Weiss et al., J. Phys. Chem. C, 2009, 30, 13331-13340). Furthermore, a fully reduced Pt metal surface (Pt0) is more active for NO oxidation.

[0006] It is believed that the phenomenon of particle sintering, for example, within catalyst compositions containing platinum group metals, occurs by one of two limiting mechanisms, namely, Ostwald ripening or particle migration and coalescence. See, for example, Hansen et al., Acc. Chem. Res. 2013, 46(8): 1720-1730, the publication of which is incorporated herein by reference. Under the Ostwald ripening mechanism, it is assumed that the metal particles are immobile and sintering occurs only due to the migration of atoms or clusters of small particles to large particles. Under the Petition 870260065670, dated 03 / 07 / 2026, page 12 / 92 4 / 72 Particle migration and coalescence sintering mechanism: particles are understood to move in a Brownian-type motion on the support surface, with subsequent coalescence leading to particle growth. By one or both mechanisms, a significant loss (usually up to 50%) of NO oxidation activity can be observed after aging of conventional Pt-based diesel oxidation catalysts.

[0007] Although the addition of palladium (Pd) to Pt-based diesel oxidation catalysts can inhibit Pt sintering and improve CO and hydrocarbon oxidation performance after high-temperature aging, a high concentration of Pd can decrease the activity of Pt to convert hydrocarbons and / or oxidize NO, especially when used with hydrocarbon storage materials, and can also make the catalyst more susceptible to sulfur poisoning. Consequently, it would be advantageous to provide a catalyst composition comprising Pt that is not so susceptible to surface area loss to allow for consistently high catalytic efficiency under high-temperature operating conditions.Furthermore, there is an ongoing need to provide catalytic compositions that utilize metals (e.g., platinum group metals) efficiently and remain effective in meeting regulations for the conversion of hydrocarbons, NOx, and CO over extended periods, particularly under high-temperature conditions. Description of the Invention

[0008] Catalyst compositions, catalyst articles, and catalyst systems comprising such catalyst articles are disclosed in this document. In some embodiments, catalyst compositions, catalyst articles, and catalyst systems comprising such catalyst articles exhibit aging stability. Petition 870260065670, dated 03 / 07 / 2026, page 13 / 92 5 / 72 improved oxidation performance. In some embodiments, an oxidation catalyst composition comprising a plurality of platinum group metal particles with a multimodal particle size distribution wherein the plurality of platinum group metal particles are of two distinct and well-defined particle size ranges exhibits less NOx loss oxidation performance after roughing and / or aging compared to oxidation catalyst compositions that do not include such a multimodal distribution of platinum group metal particles.

[0009] Therefore, in one aspect, an oxidation catalyst composition comprises a plurality of platinum group metal particles with a multimodal particle size distribution, wherein the plurality of platinum group metal particles comprises a first population of platinum group metal particles with a particle size range from about 0.5 nm to about 3 nm, and a second population of platinum group metal particles with a particle size range from about 4 nm to about 15 nm.

[0010] In some embodiments, the first population of platinum group metal particles has a particle size distribution characterized by an average particle size of about 1 nm and at least about 80% of the first population of platinum group metal particles has a particle size within about 1 nm of the average particle size.

[0011] In some embodiments, the second population of platinum group metal particles has a particle size distribution characterized by an average particle size of about 6 nm and at least about 80% of the second population of platinum group metal particles has a particle size within about 2 nm of the average particle size. Petition 870260065670, dated 03 / 07 / 2026, page 14 / 92 6 / 72 average particle size.

[0012] In some embodiments, the weight ratio between the first population of platinum group metal particles and the second population of platinum group metal particles is about 10:90 to about 90:10. In some embodiments, the weight ratio between the first population of platinum group metal particles and the second population of platinum group metal particles is about 50:50 to about 90:10. In some embodiments, the weight ratio between the first population of platinum group metal particles and the second population of platinum group metal particles is about 50:50 to about 75:25.

[0013] In some embodiments, the plurality of platinum group metal particles has an average particle size of about 3 nm to about 12 nm. In some embodiments, the plurality of platinum group metal particles has an average particle size of about 3 nm to about 10 nm. In some embodiments, the plurality of platinum group metal particles has an average particle size of about 3 to about 8 nm. In some embodiments, the plurality of platinum group metal particles has an average particle size of about 3 to about 6 nm. In some embodiments, the plurality of platinum group metal particles has an average particle size of about 3 to about 5 nm.

[0014] In some embodiments, at least about 90% of the platinum group metal is in a fully reduced form.

[0015] In some embodiments, the platinum group metal comprises platinum, palladium, ruthenium, rhodium, iridium, or combinations thereof. In some embodiments, the platinum group metal comprises platinum, palladium, or combinations thereof. In some embodiments, the platinum group metal is platinum.

[0016] In some embodiments, the catalyst composition of Petition 870260065670, dated 03 / 07 / 2026, p. 15 / 92 7 / 72 oxidation further comprises at least one refractory metal oxide support. In some embodiments, the at least one refractory metal oxide support comprises alumina (AbO3), silica (SiO2), zirconia (ZrO2), titania (TO2), ceria (CeO2), or combinations thereof. The combinations may be in the form of physical mixtures or chemical mixtures. In some embodiments, the at least one refractory metal oxide support comprises AbO3 doped with SO2, TO doped with SiO2, and / or ZrO2 doped with SiO2. In some embodiments, the at least one refractory metal oxide support comprises AbO3 doped with 1 to 10% SiO2, TiO2 doped with 1 to 20% SiO2, and / or ZrO2 doped with 1 to 30% SiO2.

[0017] In some embodiments, the first population of platinum group metal particles and the second population of platinum group metal particles are both dispersed on the same refractory metal oxide support. In some embodiments, the first population of platinum group metal particles and the second population of platinum group metal particles are each dispersed on separate refractory metal oxide supports, wherein the first population of platinum group metal particles is dispersed on a first refractory metal oxide support, and the second population of platinum group metal particles is dispersed on a second refractory metal oxide support, wherein the first refractory metal oxide support and the second refractory metal oxide support are each independently selected.In some embodiments, the first refractory metal oxide support and the second refractory metal oxide support comprise the same refractory metal oxide support material. In some embodiments, the refractory metal oxide support material comprises TiO2 or TiO2 doped with SiO2.

[0018] In another aspect, an oxidation catalyst article comprises a substrate having an inlet end and an Petition 870260065670, dated 03 / 07 / 2026, page 16 / 92 8 / 72 outlet end defining a total length and a catalytic coating comprising one or more washcoats arranged therein, wherein at least one of the coating layers comprises the oxidation catalyst composition as disclosed herein.

[0019] In some embodiments, the substrate is a continuous flow monolith or a wall flow filter.

[0020] In some embodiments, the oxidation catalyst article is a diesel oxidation catalyst article. In some embodiments, the plurality of platinum group metal particles is arranged on the substrate with a charge of about 0.176 g / l (5 g / ft3) to about 7.06 g / l (200 g / ft3).

[0021] In some embodiments, the oxidation catalyst article is a catalyzed soot filter article. In some embodiments, the plurality of platinum group metal particles is arranged on the substrate with a charge of about 0.0176 g / l to about 1.06 g / l (0.5 g / ft3 to about 30 g / ft3).

[0022] In some embodiments, the oxidation catalyst article, after aging at 650 °C for 5 hours, exhibits a NO2 / NOx ratio of about 40% to about 55% when disposed on a 2.54 cm x 7.62 cm (1” x 3”) passage substrate at a platinum group metal loading of 0.06 g / l (1.7 g / ft3) and subjected to a feed gas containing 600 ppm NO, 10% O2, 5% CO2, 5% H2O and 33 ppm propane at a temperature of 350 °C and a space velocity of 50,000 per hour.

[0023] In some embodiments, the oxidation catalyst article, after degradation at 550 °C for 5 hours, has a first NO2 / NOx ratio and, after aging at 650 °C for 5 hours, has a second NO2 / NOx ratio; wherein the second NO2 / NOx ratio is at least about 80% of the first NO2 / NOx ratio, when the oxidation catalyst article is Petition 870260065670, dated 03 / 07 / 2026, page 17 / 92 9 / 72 disposed on a 2.54 cm x 7.62 cm (1” x 3”) flow substrate in a platinum group metal loading of 0.06 g / l (1.7 g / ft3) and subjected to a feed gas containing 600 ppm NO, 10% O2, 5% CO2, 5% H2O and 33 ppm propane at a temperature of 350 °C and a space velocity of 50,000 per hour.

[0024] In another aspect, an exhaust gas treatment system comprises the oxidation catalyst article as disclosed in this document, wherein the oxidation catalyst article is downstream and in fluid communication with an internal combustion engine. In some embodiments, the exhaust gas treatment system further comprises one or more catalytic articles selected from a urea injector, a selective catalytic reduction (SCR) catalyst, an ammonia oxidation catalyst (AMOx), a low-temperature NOx adsorbent (LT-NA), and a lean NOx trap (LNT).

[0025] In another aspect, a method is provided for treating an exhaust gas stream comprising hydrocarbons, carbon monoxide and / or NOx, wherein the method comprises passing the exhaust gas stream through the catalytic article or exhaust gas treatment system as disclosed herein. In some embodiments, the exhaust gas stream comprises hydrocarbons and carbon monoxide, hydrocarbons and NOx, or carbon monoxide and NOx.

[0026] These and other features, aspects and advantages of the disclosure will become apparent from a reading of the detailed description below, together with the attached drawings, which are briefly described below. The disclosure includes any combination of two, three, four or more of the embodiments mentioned above, as well as combinations of any two, three, four or more features or elements set forth in this disclosure, regardless of whether such features or elements are Petition 870260065670, dated 03 / 07 / 2026, page 18 / 92 10 / 72 expressly combined into a specific modality description in this document. Brief Description of the Figures

[0027] In order to provide an understanding of the disclosure modalities, reference is made to the attached drawings, in which reference numerals refer to components of exemplary disclosure modalities. The drawings are merely illustrative and should not be interpreted as limiting the disclosure. The disclosure described in this document is illustrated by way of example and not as a form of limitation in the attached figures. For simplification and clarity of illustration, features illustrated in the figures are not necessarily sketched to scale. Furthermore, where deemed appropriate, reference identifications have been repeated between figures to indicate corresponding or analogous elements.

[0028] Figure 1 represents a perspective view of a honeycomb-type substrate that may comprise a catalyst washcoat composition (i.e., a selective catalytic reduction catalyst) according to some exemplary embodiments.

[0029] Figure 2 represents a cross-sectional view of a section of an exemplary wall flow filter substrate.

[0030] Figure 3A represents a cross-sectional view of an exemplary embodiment of a layered catalytic article.

[0031] Figure 3B represents a cross-sectional view of an exemplary embodiment of a zoned catalytic article.

[0032] Figure 3C represents a cross-sectional view of an exemplary embodiment of a layered and zoned catalytic article.

[0033] Figure 4 represents an emissions treatment system comprising an exemplary article of a diesel oxidation catalyst. Petition 870260065670, dated 03 / 07 / 2026, page 19 / 92 11 / 72

[0034] Figure 5 represents NO2 degradation production of exemplary modes.

[0035] Figure 6 represents NO2 degradation production at various temperatures for exemplary modes.

[0036] Figure 7 represents the NO oxidation performance for exemplary modalities.

[0037] Figure 8 represents the change in NO oxidation performance for exemplary modalities passed through degreening and aged.

[0038] Figure 9 represents the hydrocarbon and carbon monoxide oxidation performance for exemplary grades that have undergone degreening and aging.

[0039] Figure 10 represents the change in NO oxidation performance for exemplary models that have undergone degreening and aged over several engine test cycles.

[0040] Catalysts, catalyst articles and catalyst systems comprising such catalyst articles suitable for the oxidation of one or more exhaust gas components (e.g., CO, hydrocarbons and NOx) are disclosed in this document. In some respects, these are catalysts comprising a plurality of platinum group metal particles with a multimodal particle size distribution and exhibiting enhanced stability with respect to oxidation performance after definement and / or aging, compared to conventional oxidation catalysts. Definitions

[0041] As used in this document, “a” or “an” entity refers to one or more of these entities, for example, “a compound” refers to one or more compounds or at least one compound, unless otherwise indicated. Petition 870260065670, dated 03 / 07 / 2026, page 20 / 92 12 / 72 otherwise. As such, the terms “one,” “one or more,” and “at least one” are used interchangeably in this document.

[0042] Any ranges mentioned in this document are inclusive. The term “about” is used everywhere to describe and account for small variations. For example, “about” may mean that the numerical value can be modified by ±5%, ±4%, ±3%, ±2%, ±1%, ±0.5%, ±0.4%, ±0.3%, ±0.2%, ±0.1%, or ±0.05%. Numerical values ​​modified by the term “about” include the specific identified value. For example, “about 5.0” includes 5.0.

[0043] The term “reduction” means a decrease in quantity, caused by any means.

[0044] The term “associated” means, for example, “equipped with”, “connected to” or “in communication with”, for example “electrically connected” or in “fluid communication with” or otherwise connected in a way to perform a function. The term “associated” may mean directly associated or indirectly associated with, for example, by means of one or more other articles or elements.

[0045] The term “catalyst” refers to a material that promotes a chemical reaction. The catalyst includes the “catalytically active species” and the “support” that carries or sustains the active species. For example, refractory metal oxide particles can be a support for catalytic species of platinum group metals.

[0046] The term “catalytic article” in the disclosure means an article comprising a substrate having a catalyst coating composition.

[0047] As used in this document, the phrase “catalyzed soot filter” refers to a wall-flow monolith. A wall-flow filter comprises alternating inlet and outlet channels, wherein Petition 870260065670, dated 03 / 07 / 2026, page 21 / 92 13 / 72 The inlet channels are blocked at the outlet end, and the outlet channels are blocked at the inlet end. A stream of exhaust gases carrying soot entering the inlet channels is forced to pass through the filter walls before exiting the outlet channels. In addition to soot filtration and regeneration, a catalyzed soot filter can carry oxidation catalysts to oxidize CO and hydrocarbons into CO2 and H2O, or oxidize NO into NO2 to accelerate downstream SCR catalysis or to facilitate the oxidation of soot particles at lower temperatures. An SCR catalyst composition can also be directly coated onto a wall-flow filter, which is called SCRoF.

[0048] As used in this document, the phrase “catalyst system” refers to a combination of two or more catalysts, for example, a combination of a first low-temperature NOx adsorbent catalyst (LT-NA) and a second catalyst which may be a diesel oxidation catalyst, an LNT or an SCR catalyst article. The catalyst system may alternatively be in the form of a washcoat in which the two catalysts are mixed together or coated in separate layers.

[0049] The term “configured”, as used in the description and claims, is intended to be an open term, as are 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”.

[0050] As used in this document, a “diesel oxidation catalyst” converts hydrocarbons and carbon monoxide in the exhaust gas of a diesel engine, as well as oxidizing nitric oxide (NO) into nitrogen dioxide (NO2). For example, a diesel oxidation catalyst may comprise one or more platinum group metals, such as palladium and / or Petition 870260065670, dated 03 / 07 / 2026, page 22 / 92 14 / 72 platinum; a support material, such as alumina; a zeolite for hydrocarbon storage; and optionally, promoters and / or stabilizers.

[0051] In general, the term “effective” means, for example, from about 35% to 100% effective, for example, from about 40%, about 45%, about 50% or about 55% to about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90% or about 95%, in relation to the defined catalytic activity or storage / release activity, by weight or by mole.

[0052] 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 comprises gaseous components and may be, for example, exhaust from a lean-burn engine, which may contain certain non-gaseous components such as liquid droplets, solid particulates and the like. The exhaust gas stream from a combustion engine may also comprise combustion products (CO2 and H2O), products of incomplete combustion (carbon monoxide (CO) and hydrocarbons), nitrogen oxides (NOx), fuel and / or carbonaceous particulate matter (soot), and unreacted oxygen and nitrogen.As used in this document, the terms “upstream” and “downstream” refer to relative directions according to the flow of an exhaust gas stream from an engine towards an exhaust pipe, with the engine at an upstream location and the exhaust pipe and any pollution abatement devices, such as filters and catalytic converters, being downstream of the engine. The inlet end of a substrate is synonymous with the “upstream” or “front” end. The outlet end is synonymous with the “downstream” or “rear” end. An upstream zone is upstream of a downstream zone. An upstream zone may be closer to the engine. Petition 870260065670, dated 03 / 07 / 2026, page 23 / 92 15 / 72 or collector and a downstream zone may be further away from the engine or collector.

[0053] The term “in fluid communication” is used to refer to articles positioned on the same escape line, that is, a common escape stream passes through the articles that are in fluid communication with each other. Articles in fluid communication may be adjacent to each other on the escape line. Alternatively, articles in fluid communication may be separated by one or more articles, also called “washcoat monoliths”.

[0054] The term “functional article” in the disclosure means an article comprising a substrate having a functional coating composition disposed thereon, such as a catalyst and / or a sorbent coating composition.

[0055] As used in this document, “impregnated” or “impregnation” refers to the permeation of the catalytic material into the porous structure of the support material.

[0056] As used in this document, “LNT” refers to a poor NOx trap, which is a catalyst containing a platinum group metal, ceria, and an alkaline earth trap material suitable for adsorbing NOx under poor conditions (e.g., BaO or MgO). Under better conditions, the NOx is released and reduced to nitrogen.

[0057] As used in this document, the terms “nitrogen oxides” or “NOx” refer to nitrogen oxides, such as NO, NO2 or N2O.

[0058] The terms “on” and “above” in reference to a coating layer may be used synonymously. The term “directly on” means in direct contact with. The disclosed articles are referred to in certain embodiments as comprising a coating layer “over” a second coating layer, and such language is intended to encompass Petition 870260065670, dated 03 / 07 / 2026, page 24 / 92 16 / 72 modalities with intermediate layers, where direct contact between the coating layers is not necessary (i.e., “on” is not equivalent to “directly on”).

[0059] As used in this document, the term “promoted” refers to a component that is intentionally added to a molecular sieve material, such as, for example, by means of ion exchange, as opposed to impurities inherent in the molecular sieve.

[0060] As used in this document, the term “selective catalytic reduction” (SCR) refers to the catalytic process of reducing nitrogen oxides to dinitrogen (N2) using a nitrogen-based reducing agent.

[0061] “Substantially free” means “little or none” or “none intentionally added” and also allows for only trace and / or inadvertent amounts. For example, in certain embodiments, “substantially free” means less than 2% by weight (percent by weight), less than 1.5% by weight, less than 1.0% by weight, less than 0.5% by weight, less than 0.25% by weight or less than 0.01% by weight, based on the weight of the stated total composition.

[0062] As used in this document, the term “substrate” refers to the monolithic material onto which the catalyst composition, i.e., catalytic coating, is applied, for example in the form of a washcoat. In one or more embodiments, the substrates are direct-flow monoliths and monolithic wall-flow filters. Continuous-flow and wall-flow substrates are also taught, for example, in International Application Publication WO2016 / 070090, which is incorporated herein by reference. A washcoat is formed by preparing a fluid paste containing a specified solids content (e.g., 30% to 90% by weight) of catalyst in a liquid which is then coated onto a substrate and dried to provide a washcoat layer. The reference to “monolithic substrate” Petition 870260065670, dated 03 / 07 / 2026, page 25 / 92 17 / 72 signifies a unitary structure that is homogeneous and continuous from inlet to outlet. A washcoat is formed by preparing a fluid paste containing a certain solids content (e.g., 20% to 90% by weight) of particles in a liquid vehicle which is then coated onto a substrate and dried to provide a washcoat layer.

[0063] As used in this document, the term “support” refers to any high surface area material, usually a refractory metal oxide material, onto which a catalytic precious metal is applied.

[0064] As used in this document, the term “washcoat” has its usual meaning in the art of a thin, adherent coating of a catalytic material or other material applied to a substrate material, such as a honeycomb-type substrate, that is sufficiently porous to allow the passage of the gas stream being treated. The washcoat containing platinum group metal particles may optionally comprise a binder selected from silica, alumina, titania, zirconia, ceria, or a combination thereof. The binder loading is about 0.1 to 10% by weight based on the weight of the washcoat. As used in this document and described in Heck, Ronald and Farrauto, Robert, Catalytic Air Pollution Control, New York: Wiley-Interscience, 2002, pp. 18–19, a washcoat layer includes a compositionally distinct layer of material disposed on the surface of a monolithic substrate or an underlying washcoat layer.A substrate may contain one or more washcoat layers, and each washcoat layer may be different in some way (for example, it may differ in physical properties such as particle size) and / or may differ in chemical catalytic functions.

[0065] “Percent by weight (% by weight)”, unless otherwise indicated, is based on a whole composition free of any volatiles, i.e., based on dry solids content. Unless otherwise indicated, all Petition 870260065670, dated 03 / 07 / 2026, page 26 / 92 18 / 72 parts and percentages are by weight.

[0066] As used in this document, “space velocity” is the number of volumes of gas or liquid that pass over or through a unit volume (such as, for example, a catalyst) per unit time.

[0067] A selective catalytic reduction catalyst is a catalyst capable of selectively reducing nitrogen oxides.

[0068] Ammonia oxidation catalysts are catalysts capable of oxidizing ammonia.

[0069] Low-temperature NOx adsorbers absorb NOx at a lower temperature typically associated with the cold start period of a diesel engine and release the absorbed NOx at higher temperatures typically associated with more efficient reduction by a selective catalytic reduction catalyst.

[0070] All methods described in this document may be performed in any appropriate order unless otherwise indicated in this document or otherwise clearly contradicted by the context. The use of any and all examples or exemplary language (e.g., “like”) provided herein is intended only to better clarify the materials and methods and does not represent a limitation on scope unless otherwise indicated. No language in the descriptive report should be construed as indicating any unclaimed element as essential to the practice of the materials and methods disclosed. All U.S. patent applications, pre-grant publications, and patents referenced herein are incorporated herein by reference in their entirety. Oxidation Catalyst Composition

[0071] In one aspect, an oxidation catalyst composition comprises a plurality of platinum group metal particles. Petition 870260065670, dated 03 / 07 / 2026, page 27 / 92 19 / 72 with a multimodal particle size distribution, the plurality of platinum group metal particles comprising a first population of platinum group metal particles having a particle size range from about 0.5 to about 3 nm; and a second population of platinum group metal particles with a particle size range from about 4 to about 15 nm. Platinum Group Metal (Mgp)

[0072] Platinum group metals include platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), osmium (Os), iridium (Ir), and mixtures thereof. The platinum group metal may be in metallic form, with zero valence, or the platinum group metal may be in oxide form. In some embodiments, the platinum group metal is a metal or oxide thereof (e.g., including, but not limited to, platinum or an oxide thereof). Advantageously, the platinum group metal (or metals) is substantially in fully reduced form, meaning that at least about 90% of the platinum group metal content is reduced to the metallic form (platinum group metal (0)).In some embodiments, the amount of platinum group metal in the fully reduced form is even greater, for example, at least about 92%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% of the platinum group metal is in the fully reduced form. The amount of platinum group metal(0) can be determined using ultrafiltration, followed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), or by X-ray photoelectron spectroscopy (XPS).

[0073] In some embodiments, the platinum group metal comprises platinum, palladium, ruthenium, rhodium, iridium, or a combination thereof. In some embodiments, the platinum group metal comprises Petition 870260065670, dated 03 / 07 / 2026, p. 28 / 92 20 / 72 platinum, palladium, or a combination thereof. Exemplary weight ratios for such Pt / Pd combinations include weight ratios of about 1:10 to about 10:1 Pt:Pd, such as equal to or greater than about 1:1 Pt:Pd, equal to or greater than about 1.5:1 Pt:Pd, or equal to or greater than about 2:1 Pt:Pd. In certain embodiments, the platinum group metal is Pd. In certain embodiments, the platinum group metal is Pt.

[0074] The concentration of platinum group metal (e.g., Pt and / or Pd) present in an oxidation catalyst composition may vary, but can be from about 1% by weight to about 10% by weight relative to the weight of the composition. PGM Particles

[0075] Platinum group metal particles are particles comprising one or more platinum group metals. The size of the platinum group metal particles in the catalyst composition, as disclosed herein, may vary. As disclosed herein, the oxidation catalyst composition comprises a plurality of platinum group metal particles with a multimodal particle size distribution.

[0076] As used in this document, “particle size” refers to the smallest diameter sphere that will completely enclose the particle, and this measurement refers to an individual particle as opposed to an agglomeration of two or more particles. Particle size can be measured by laser light scattering techniques with dispersions or dry powders, for example, according to ASTM standard method D4464. Particle size can also be measured by Scanning Electron Microscopy (SEM) or Transmission Electron Microscopy (TEM) for submicron-sized particles; or by a particle size analyzer for particles containing support (micron size). Petition 870260065670, dated 03 / 07 / 2026, page 29 / 92 21 / 72

[0077] In addition to TEM, carbon monoxide (CO) chemisorption can be used for average particle size determination. This technique may not differentiate between various platinum group metal species (e.g., Pt, Pd, etc., compared to XRD, TEM, and SEM) and only determines the average particle size. To determine the average particle size by CO chemisorption, catalyst washcoat samples were milled and a small amount (~100 mg) was analyzed by pulsed CO injection as follows: Pretreatment: drying at 150 °C in helium, followed by heating at 400 °C in a 5% hydrogen atmosphere in nitrogen; CO chemisorption: sample pulsed at room temperature with 10% CO in helium.

[0078] As used in this document, “particle size distribution” defines the relative quantity of particles in a particle population with particle sizes within a range.

[0079] As used in this document, “multimodal particle size distribution” refers to a continuous probability distribution with two or more modes, which appear as two or more distinct peaks (local maxima) in the probability density function. This can be visualized by plotting the frequency against the logarithm of the particle size for the particle population. Particle size distributions and percentages of particles with sizes within a particular range can be determined, for example, from TEM or SEM by coating calcined supported platinum group metal particles onto a substrate.For example, calcined supported platinum group metal particles on a substrate can be analyzed directly by TEM or SEM (by observing the coated substrate) or can be analyzed by scraping or removing at least a portion of the calcined supported platinum group metal particles from the substrate and obtaining an image of them. Petition 870260065670, dated 03 / 07 / 2026, page 30 / 92 22 / 72 supported platinum group metal particles scraped / removed.

[0080] In some embodiments, the plurality of platinum group metal particles comprises a first population and a second population of platinum group metal particles with different size ranges. In some embodiments, the plurality of platinum group metal particles comprises a first population with a particle size range from about 0.5 nm to about 3 nm and a second population of platinum group metal particles with a particle size range from about 4 nm to about 15 nm. In some embodiments, the second population of platinum group metal particles may be colloidal platinum group metal particles.

[0081] In some embodiments, the first population of platinum group metal particles and the second population of platinum group metal particles each have an average particle size. In some embodiments, the first population of platinum group metal particles has an average particle size of about 1 nm. In some embodiments, the second population of platinum group metal particles has an average particle size of about 6 nm.

[0082] As used herein, the term “average particle size” refers to a particle characteristic that indicates, on average, the diameter of the particles. “Average particle size” is synonymous with D50, meaning that half of the particle population has a particle size above this point, and half below. The D90 particle size distribution indicates that 90% of the particles (by number) have a Feret diameter below a given size. The average particle size can be measured, for example, by transmission electron microscopy (TEM) by visually examining a TEM image, measuring the diameter of the particles in the image, and calculating the measured average particle size based on the magnification of the Petition 870260065670, dated 03 / 07 / 2026, page 31 / 92 23 / 72 There is an image.

[0083] The reference in this document to average particle size reflects the average particle size of fresh and / or calcined material, for example, determined after calcination of the particles but before aging of the particles. By “fresh” it is understood that the particles have not been subjected to temperatures exceeding about 500 °C. In some embodiments, the oxidation catalyst composition is fresh. In other embodiments, the oxidation catalyst composition may be referred to as degreening-passed. As used in this document, the term “degreening-passed” refers to a catalyst composition that has been subjected to a temperature of about 500 to 550 °C for a period of time (e.g., for about 1 to 5 hours) with simulated engine exhaust or exhaust gas. In some embodiments, the oxidation catalyst composition may be referred to as aged.As used in this document, the term “aged” refers to a catalyst composition that has been subjected to temperatures of about 650 °C or more (e.g., about 650 °C, 700 °C, 800 °C, 900 °C, or 1,000 °C) for a period of time (e.g., from about 5 hours to about 100 hours, or from about 100 hours to about 1,000 hours). As will be recognized by one skilled in the art, subjecting a platinum group metal particle to degradation or aging conditions can induce changes in particle sizes as described above in this document.

[0084] In some embodiments, particle populations may be characterized in that at least 80% of the particles have a particle size within 50 percent of the average particle size for the particle population, or within 20 percent, or within 15 percent, within 10 percent, or within 5 percent (i.e., in which at least 80% of all particles in the population have a particle size within Petition 870260065670, dated 03 / 07 / 2026, page 32 / 92 24 / 72 of the given percentage range around the average particle size). In other embodiments, at least 85%, 90%, 95%, 96%, 97%, 98%, or 99% of all particles are within these ranges. In some embodiments, the particle populations comprise particles in which at least 80% of the particles have a particle size within about 1 nm of the average particle size, or within about 2 nm of the average particle size.

[0085] In some embodiments, the first population of platinum group metal particles has a particle size distribution characterized by an average particle size of about 1 nm and at least 80% of the first population of platinum group metal particles (or at least 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100%) have a particle size within 1 nm of the average particle size, for example, in the range of about 0.001, about 0.01 nm or about 0.1, to about 2 nm.

[0086] In some embodiments, the second population of platinum group metal particles has a particle size distribution characterized by an average particle size of about 6 nm and at least about 80% of the second population of platinum group metal particles (or at least 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100%) have a particle size within about 2 nm of the average particle size, for example, in the range of about 4 nm, about 5 nm, about 6 nm, about 7 nm or about 8 nm.

[0087] The relative amounts of the two populations of platinum group metal particles may vary. In some embodiments, the weight ratio between the first population of platinum group metal particles and the second population of platinum group metal particles is from about 10:90 to about 90:10. In some embodiments, the weight ratio between the first population of platinum group metal particles and the second Petition 870260065670, dated 03 / 07 / 2026, p. 33 / 92 In some embodiments, the weight ratio between the first population of platinum group metal particles and the second population of platinum group metal particles is about 50:50 to about 90:10.

[0088] The average particle size for the plurality of platinum group metal particles (i.e., the overall average particle size for the two populations combined) can vary, depending on both the ratio of the two populations and the average particle size within each population. In some embodiments, the plurality of platinum group metal particles has an average particle size of about 3 to about 12 nm, for example, about 3 to about 10 nm; about 3 to about 8 nm; about 3 to about 6 nm; or about 3 to about 5 nm. Refractory Metal Oxide Support Materials

[0089] In some embodiments, the oxidation catalyst composition further comprises at least one refractory metal oxide support material. As used herein, “refractory metal oxide” refers to porous metal-containing oxide materials exhibiting chemical and physical stability at high temperatures, such as the temperatures associated with diesel engine exhaust. Exemplary refractory oxides include alumina, silica, zirconia, titania, ceria, and physical mixtures or chemical combinations thereof, including atomically doped combinations and including high surface area or activated compounds, such as activated alumina. Exemplary aluminas include large-pore boehmite, gamma-alumina, and delta / theta alumina. Useful commercial aluminas include activated aluminas, such as high-density bulk gamma-alumina, low- or medium-density bulk large-pore gamma-alumina, and low-density bulk large-pore boehmite and gamma-alumina. Petition 870260065670, dated 03 / 07 / 2026, p. 34 / 92 26 / 72

[0090] High surface area refractory oxide supports, such as alumina support materials, also referred to as “gamma alumina” or “activated alumina”, can exhibit a BET surface area greater than 60 m² / g, often up to about 200 m² / g or higher. This activated alumina is generally a mixture of the gamma and delta alumina phases, but may also contain substantial amounts of the eta, kappa, and theta alumina phases. “BET surface area” has its usual meaning of referring to the Brunauer, Emmett, Teller method for determining surface area by N₂ adsorption. In some embodiments, the activated alumina has a specific surface area of ​​60 to 350 m² / g and in some embodiments 90 to 250 m² / g.

[0091] In some embodiments, the refractory metal oxide comprises alumina (AbOa), silica (SiO2), zirconia (ZrO2), titania (TO2), ceria (CeO2), or combinations thereof. The combinations may be in the form of physical or chemical mixtures. Mixed metal oxides include, but are not limited to, zirconia-alumina, ceria-zirconia, ceria-alumina, lanthana-alumina, baria-alumina, and silica-alumina.

[0092] In certain embodiments, useful metal oxide supports in the oxidation catalyst compositions disclosed in this document are doped alumina materials, such as Si-doped alumina materials (including, but not limited to, 1 to 10% SiO2-Al2Oa), doped titania materials, such as Si-doped titania materials (including, but not limited to, 1 to 10% SiO2-TiO2), or doped zirconia materials, such as Si-doped ZrO2 (including, but not limited to, 5 to 30% SiO2-ZrO2). Consequently, in some embodiments, at least one refractory metal oxide support comprises SiO2-doped AbOa, SiO2-doped TO2, and / or SiO2-doped ZrO2.

[0093] The oxidation catalyst composition may comprise any of the refractory metal oxides mentioned above and Petition 870260065670, dated 03 / 07 / 2026, p. 35 / 92 27 / 72 in any quantity. For example, refractory metal oxides in the catalyst composition comprise about 15% by weight, about 20% by weight, about 25% by weight, about 30% by weight, about 35% by weight, about 40% by weight, about 45% by weight, about 50% by weight to about 55% by weight, about 60% by weight, about 65% by weight, about 70% by weight, about 75% by weight, about 80% by weight, about 85% by weight, about 90% by weight, about 95% by weight or about 99% by weight, based on the total dry weight of the catalyst composition. The catalyst composition may, for example, comprise from about 10 to about 99% by weight of TiO2 or TiO2 doped with SiO2, from about 15 to about 95% by weight of TiO2 or TiO2 doped with SiO2, or from about 20 to about 85% by weight of TO or TO doped with SiO2.

[0094] In some embodiments, the first population of platinum group metal particles and the second population of platinum group metal particles are both dispersed on the same refractory metal oxide support. In some embodiments, the first population of platinum group metal particles and the second population of platinum group metal particles are each dispersed on separate refractory metal oxide supports, wherein the first population of platinum group metal particles is dispersed on a first refractory metal oxide support, and the second population of platinum group metal particles is dispersed on a second refractory metal oxide support, wherein the first refractory metal oxide support and the second refractory metal oxide support are each independently selected.

[0095] In some embodiments, the first refractory metal oxide support and the second refractory metal oxide support are two different refractory metal oxide materials (for example, as a non-limiting example, the first refractory metal oxide support may be alumina and Petition 870260065670, dated 03 / 07 / 2026, page 36 / 92 28 / 72 the second refractory metal oxide support may be titania). In some embodiments, the first refractory metal oxide support and the second refractory metal oxide support comprise the same refractory metal oxide support material. In some embodiments, the first and second refractory metal oxide supports comprise TiO2 or TiO2 doped with SO2. Dispersion of Platinum Group Metal Particles on a Refractory Metal Oxide Support

[0096] The oxidation catalyst compositions as disclosed herein may comprise two populations of platinum group metal particles associated with one or more support materials, for example, refractory metal oxide supports. The methods for dispersing platinum group metal particles in a refractory metal oxide support may vary depending, for example, on the size range of the platinum group metal particles.

[0097] In some embodiments, a first population of platinum group metal particles with a particle size range of about 0.5 to about 3 nm is dispersed on a refractory metal oxide support. In some embodiments, such supported particles are prepared by impregnating the refractory metal oxide support material in particulate form with a platinum group metal precursor solution, such as an aqueous solution of water-soluble platinum group metal compounds or complexes, such as palladium or platinum in the form of nitrate, acetate, a tetraamine complex (e.g., chloride nitrate, acetate and the like), or a combination thereof. After impregnation and drying, calcination is optionally performed to convert the platinum group metal compound(s) into a more catalytically active zero-valence form.Multiple platinum group metals (e.g., platinum and palladium) can be impregnated simultaneously or separately. Petition 870260065670, dated 03 / 07 / 2026, page 37 / 92 29 / 72 can be impregnated onto the same refractory metal oxide support particles or separate refractory metal oxide support particles, using, for example, an incipient moisture technique.

[0098] Incipient moisture impregnation techniques, also called capillary impregnation or dry impregnation, are commonly used for the synthesis of such heterogeneous materials, i.e., catalysts. In some embodiments, an aqueous solution of a platinum group metal compound is added to a refractory metal oxide support containing the same pore volume as the volume of the solution that was added. Capillary action draws the solution into the pores of the refractory metal oxide support. Adding a solution in excess of the support pore volume can cause the solution transport to change from a capillary action process to a diffusion process, which is much slower. In some embodiments, the support particles are sufficiently dry to absorb substantially all of the solution to form a wet solid.

[0099] In some embodiments, the impregnated refractory metal oxide support can then be dried, such as by heat treatment of the particles at an elevated temperature (e.g., 100 to 150 °C) for a period of time (e.g., 1 to 3 hours) to remove volatile components within the solution and then calcined to convert the platinum group metal components into a more catalytically active form, depositing the active platinum group metal onto the refractory metal oxide support surface. An exemplary calcination process involves heat treatment in air at a temperature of about 400 to 550 °C for 0.5 to 3 hours. The maximum loading may be limited by the solubility of the precursor in the solution. The concentration profile of the impregnated material may depend on the mass transfer conditions within the pores during impregnation and drying. The above process can be repeated as needed. Petition 870260065670, dated 03 / 07 / 2026, page 38 / 92 30 / 72 is required to achieve the desired level of platinum group metal impregnation.

[0100] In some embodiments, a second population of platinum group metal particles with a particle size range of about 4 to about 15 nm is dispersed on a refractory metal oxide support. The dispersion can be achieved during the production of the platinum group metal particles (direct dispersion) and / or after the production of the platinum group metal particles (subsequent dispersion). Each method is described below in this document. Direct Dispersion in Supporting Material

[0101] In some embodiments, platinum group metal particles can be dispersed in refractory metal oxide support materials during the production of platinum group metal particles. An exemplary method for producing platinum group metal particles in the desired size range (e.g., from about 4 to about 15 nm) is described in International Patent Application Publication No. WO2016 / 057692, which is incorporated herein by reference in its entirety. Briefly, as disclosed herein, platinum group metal precursors (e.g., platinum group metal salts) are combined with a dispersion medium and a polymer suspension stabilizing agent, and the resulting solution is combined with a reducing agent to provide a colloidal dispersion of platinum group metal particles.To disperse platinum group metal particles in a refractory metal oxide support, the refractory metal oxide support material can be added to the dispersion in which the platinum group metal particles are formed at any stage of the process (e.g., along with platinum group metal precursors or along with the reducing agent) to disperse the particles in the refractory metal oxide support material. Before. Petition 870260065670, dated 03 / 07 / 2026, page 39 / 92 31 / 72 of this addition, the dispersion of platinum group metal particles can optionally be concentrated or diluted. Exemplary methods for impregnating supports with colloidal platinum group metal materials are described in document US2017 / 0304805 for Xu et al. and document US2019 / 0015781 for Wei et al., both incorporated by reference herein in their entirety.

[0102] In some embodiments, platinum group metal particles are isolated and subsequently dispersed in the refractory metal oxide support material. Methods for isolating particles from a dispersion are generally known, and in some embodiments, isolated platinum group metal particles can be obtained by heating and / or applying vacuum to a dispersion containing particles or processing the dispersion to ensure the removal of at least a substantial portion of the solvent from it. After isolating the platinum group metal particles, the platinum group metal particles and the refractory metal oxide support can be mixed (e.g., with water) to form a dispersion in which the platinum group metal particles can be dispersed in the refractory metal oxide support material.These methods, which provide dispersion in a refractory metal oxide support material after the formation of platinum group metal particles, are commonly described as incipient moisture techniques. This process can be repeated several times to achieve a target concentration of platinum group metal in the support.

[0103] Colloidal platinum group metal (e.g., platinum) can be prepared from a platinum group metal precursor by reduction, as described above. The platinum group metal precursor can, in some embodiments, be selected from amine complex salts, hydroxyl salts, nitrates, carboxylic acid salts, ammonium salts, and oxides (e.g., selected from Pt(NHs)4(OH)2, Pt nitrate, Pt citrate, and Petition 870260065670, dated 03 / 07 / 2026, page 40 / 92 32 / 72 similar).

[0104] The reducing agent may be any reagent effective for reducing platinum group metals to the metallic form (platinum group metal(0)) and is advantageously soluble in the dispersion medium (e.g., soluble in water). Although not limited to this, in certain embodiments, the reducing agent may be an organic reducing agent. Suitable reducing agents are, for example, hydrogen, hydrazine, urea, formaldehyde, formic acid, ascorbic acid, citric acid, glucose, sucrose, xylitol, meso-erythritol, sorbitol, glycerol, maltitol, or oxalic acid. Furthermore, liquid reducing agents, such as monovalent alcohols from the methanol group, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol, 2-methylpropan-1-ol, allyl alcohol and diacetone alcohol, and mixtures and combinations thereof may be employed. Other suitable liquid reducing agents are divalent alcohols, such as ethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol or dipropylene glycol.Other reducing agents are hydrazine-based reducing agents, such as formic hydrazide and hydroxyethylhydrazine, and natural plant-based polyphenolic acids, such as tannic acid and garlic acid. In some embodiments, the reducing agent is ascorbic acid. The reducing agent may be present in an amount of about 1 to 10% by weight in the dispersion.

[0105] The dispersion medium may be, for example, at least one polar solvent selected from water, alcohols (including polyols), dimethylformamide (DMF), and combinations thereof. The alcohol may, in some embodiments, be selected from methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, hexanol, octanol, and combinations thereof. The polyol may, in some embodiments, be selected from glycerol, glycol, ethylene glycol, diethylene glycol, triethylene glycol, butanediol, tetraethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentadiol, 1,2-hexadiol, and combinations thereof. In some Petition 870260065670, dated 03 / 07 / 2026, page 41 / 92 In 33 / 72 modalities, the dispersion medium comprises water. Some modalities are aqueous colloidal dispersions.

[0106] The stabilizing agent may be a polymer suspension stabilizing agent that is soluble in the dispersion medium and / or used to improve the dispersion of platinum group metal particles (e.g., where the dispersion medium comprises water, the stabilizing agent may be a water-soluble polymer suspension stabilizer). The composition and size (e.g., molecular weight-average weight, Mw) of the polymer may vary. In some embodiments, the polymer has an Mw of 2,000 to 2,000,000 Da, such as an Mw of 10,000 to 60,000 Da (measured using Gel Permeation Chromatography (GPC)). Suitable polymers include, for example, polyvinylpyrrolidone (PVP), a copolymer including vinylpyrrolidone as a first polymerization unit and a fatty acid substituted or unsubstituted polyoxyethylene. Polyvinylpyrrolidone can be useful as a stabilizing agent for polymer suspensions.The polymer suspension stabilizing agent may be present in an amount of about 0.1 to 20, or about 5 to 10, parts by weight based on 100 parts by weight of the dispersion medium.

[0107] In some embodiments, the refractory metal oxide support material dispersed with platinum group metal particles is then dried at elevated temperature (e.g., 100 to 150 °C) for a period of time (e.g., 1 to 3 hours). Optionally, the refractory metal oxide support material dispersed with platinum group metal particles is calcined to expel volatile components. An exemplary calcination process involves heat treatment in air at a temperature of about 400 to 550 °C for 1 to 3 hours. The above process may be repeated as necessary to achieve the desired level of impregnation.

[0108] In some embodiments, the two populations of particles Petition 870260065670, dated 03 / 07 / 2026, page 42 / 92 Platinum group metal particles (34 / 72) can be dispersed on the same refractory metal oxide support or on separate refractory metal oxide support materials, which may have the same composition or different compositions. In embodiments where the two populations of platinum group metal particles are dispersed on the same refractory metal oxide support material, the dispersion can be carried out sequentially and in any order (e.g., impregnation with a platinum group metal solution, followed by colloidal platinum group metal impregnation, or colloidal platinum group metal impregnation followed by impregnation with a platinum group metal solution). Furthermore, calcination, grinding, both, or neither can be carried out after each dispersion of the platinum group metal population is conducted. Catalytic Articles

[0109] In another aspect, an oxidation catalyst article comprises a substrate having an inlet end and an outlet end defining a total length, and a catalytic coating comprising an oxidation catalyst composition as disclosed herein disposed in at least a portion thereof. Substrates

[0110] In some embodiments, oxidation catalyst compositions are arranged on a substrate to form a catalytic article. Catalytic articles comprising substrates can be employed as part of an exhaust gas treatment system (e.g., catalyst articles including, but not limited to, articles comprising the oxidation catalyst compositions disclosed herein). In some embodiments, useful substrates are three-dimensional, having a length, diameter, and volume similar to a cylinder. The shape does not need to be... Petition 870260065670, dated 03 / 07 / 2026, page 43 / 92 35 / 72 must necessarily conform to a cylinder. In some embodiments, the length is an axial length defined by an inlet end and an outlet end.

[0111] In some embodiments, the substrate for the disclosed composition (or compositions) may be constructed of any material typically used to prepare automotive catalysts and may comprise a metal or ceramic honeycomb structure. In some embodiments, the substrate may provide a plurality of wall surfaces on which the washcoat composition is applied and adhered, thereby acting as a substrate for the catalyst composition.

[0112] Ceramic substrates can be made of any suitable refractory material, for example, cordierite, cordierite-alumina, aluminum titanate, silicon titanate, silicon carbide, silicon nitride, zirconium mullite, spodumene, alumina-silica-magnesia, zirconium silicate, sillimanite, a magnesium silicate, zirconium, petalite, α-alumina, an aluminosilicate and the like.

[0113] Substrates may also be metallic, comprising one or more metals or metal alloys. A metallic substrate may include any metallic substrate, such as those with openings or “punctures” in the channel walls. Metallic substrates may be employed in various forms, such as pellets, compressed metal fibers, corrugated sheet, and monolithic foam. Specific examples of metallic substrates include heat-resistant metal-based alloys, especially those in which iron is a major or substantial component. Such alloys may contain one or more of nickel, chromium, and aluminum, and the total of these metals may advantageously comprise at least about 15% by weight (weight percent) of the alloy, for example, about 10% by weight to about 25% by weight of chromium, about 1% by weight to about 8% by weight of aluminum, and 0% by weight to about 20% by weight of nickel, in each case based on the weight of the substrate. Petition 870260065670, dated 03 / 07 / 2026, p. 44 / 92 36 / 72 Examples of metallic substrates include those that have straight channels; those that have protruding blades along the axial channels to interrupt gas flow and to open gas flow communication between the channels; and those having blades and also holes to intensify gas transport between the channels, allowing radial gas transport throughout the monolith.

[0114] Any suitable substrate for the catalytic articles disclosed in this document may be employed, such as a monolithic substrate of the type having thin parallel gas flow passages extending through it from an inlet or outlet face of the substrate, such that passages are open for fluid flow through them (“continuous flow substrate”). Another exemplary substrate is of the type having a plurality of substantially parallel and thin gas flow passages extending along the longitudinal geometric axis of the substrate wherein, for example, each passage may be blocked at one end of the substrate body, with alternating blocked passages at opposite end faces (“wall flow filter”).Continuous flow and wall flow substrates are also taught, for example, in International Application Publication WO2016 / 070090, which is incorporated herein by reference in its entirety.

[0115] In some embodiments, the catalyst substrate comprises a honeycomb substrate in the form of a wall-flow filter or a continuous-flow substrate. In some embodiments, the substrate is a wall-flow filter. In some embodiments, the substrate is a continuous-flow substrate. Continuous-flow substrates and wall-flow filters will be discussed in more detail in this document below. Continuous Flow Substrates

[0116] In some embodiments, the substrate is a continuous flow substrate (e.g., monolithic substrate, which includes a substrate Petition 870260065670, dated 03 / 07 / 2026, page 45 / 92 37 / 72 monolithic alveolar continuous flow). Continuous flow substrates have parallel, thin gas flow passages extending from an inlet end to an outlet end of the substrate, so that the passages are open to fluid flow. The passages, which may be essentially straight paths from their fluid inlet to their fluid outlet, are defined by walls in which a catalytic coating is arranged so that the gases flowing through the passages come into contact with the catalytic material. The flow passages of the continuous flow substrate may be thin-walled channels, which may have any suitable size and cross-sectional shape, such as trapezoidal, rectangular, square, sinusoidal, hexagonal, oval, circular, etc. The continuous flow substrate may be ceramic or metallic, as described above.

[0117] Continuous flow substrates may, for example, have a volume of about 0.82 l (50 in3) to about 19.66 l (1,200 in3), a cell density (inlet openings) of about 9.29 cells per cm2 to about 77.49 cells per cm2 or up to about 139.49 cells per cm2, for example, from about 30.99 to about 61.99 cells per cm2 (60 cells per square inch (cpsi) to about 500 cpsi or up to about 900 cpsi, for example, from about 200 to about 400 cpsi) and a wall thickness of about 50 microns to about 200 microns or to about 400 microns. Wall Flow Filter Substrates

[0118] In some embodiments, the substrate is a wall-mounted flow filter, which may have a plurality of substantially parallel and thin gas flow passages extending along the longitudinal geometric axis of the substrate. In some embodiments, each passage is blocked at one end of the substrate body, with alternating passages blocked at opposite end faces. Such monolithic wall-mounted flow filter substrates may contain up to about 900 or more Petition 870260065670, dated 03 / 07 / 2026, p. 46 / 92 38 / 72 flow passages (or “cells”) per square centimeter (square inch) of cross-section. For example, the substrate may have from about 1.08 to 92.99, more generally from about 15.49 to 61.99 cells per cm2 (7 to 600, more generally from about 100 to 400 cells per square inch (“cpsi”)). The cells may have cross-sections that are rectangular, square, circular, oval, triangular, hexagonal, or other polygonal shapes. The wall-mounted flow filter substrate may be ceramic or metallic, as described above.

[0119] With reference to Figure 1, the exemplary wall-flow filter substrate has a cylindrical shape and a cylindrical outer surface with a diameter D and an axial length L. A cross-sectional view of a monolithic wall-flow filter substrate section is illustrated in Figure 2, showing alternating obstructed and open passages (cells). The blocked or obstructed ends (100) alternate with the open passages (101), with each opposite end open and blocked, respectively. The filter has an inlet end (102) and an outlet end (103). Arrows crossing porous cell walls (104) represent exhaust gas flow entering the open cell ends, diffusion through the porous cell walls (104), and exiting the open outlet cell ends. Obstructed ends (100) impede gas flow and encourage diffusion through the cell walls.Each cell wall will have an entry side (104a) and an exit side (104b). The passages are delimited by the cell walls.

[0120] The wall flow filter article substrate may have a volume of, for example, about 50 cm3, about 1,638.71 cm3(100 in3), about 3,277.41 cm3(200 in3), about 4,916.12 cm3(300 in3), about 6,554.83 cm3(400 in3), about 8,193.53 cm3(500 in3), about 9,832.24 cm3(600 in3), about 11,470.9 cm3(700 in3), about 13,109.7 cm3(800 in3), Petition 870260065670, dated 03 / 07 / 2026, page 47 / 92 39 / 72 about 14,748.4 cm3(900 in3) or about 16,387.1 cm3(1,000 in3) to about 24,580.6 cm3(1,500 in3), about 32,774.13 cm3(2,000 in3), about 40,967.66 cm3(2,500 in3), about 49,161.19 cm3(3,000 in3), about 57,354.72 cm3(3,500 in3), about 65,548.26 cm3(4,000 in3), about 73,741.79 cm3 (4,500 in3) or approximately 81,935.32 cm3 (5,000 in3). Wall-flow filter substrates may have a wall thickness of approximately 50 microns to approximately 2,000 microns, for example, approximately 50 microns to approximately 450 microns, or approximately 150 microns to approximately 400 microns.

[0121] The walls of the wall flow filter may be porous and have a wall porosity of at least about 40% or at least about 50% with an average pore diameter of at least about 10 microns before the arrangement of the functional coating. For example, the substrate of the wall flow filter article in some embodiments has a porosity of > 40%, > 50%, > 60%, > 65% or > 70%. For example, the substrate of the wall flow filter article will have a wall porosity of about 50%, about 60%, about 65% or about 70% to about 75% and an average pore diameter of about 10, or about 20, to about 30, or about 40 microns before the arrangement of a catalytic coating. The terms "wall porosity" and "substrate porosity" mean the same thing and are interchangeable. Porosity is the ratio of void volume (or pore volume) divided by the total volume of a substrate material.Pore ​​size and pore size distribution can, for example, be determined by measuring Hg porosimetry. Substrate Coating Process

[0122] In some embodiments, a substrate as described herein is coated with an oxidation catalyst composition as disclosed herein. The coatings are “catalytic coating compositions” or “catalytic coatings”. A Petition 870260065670, dated 03 / 07 / 2026, page 48 / 92 40 / 72 “catalyst composition” and a “catalytic coating composition” are synonymous.

[0123] In some embodiments, the oxidation catalyst composition is prepared and coated onto a substrate as described herein. In some embodiments, this method may comprise mixing the catalyst composition (or one or more components of the catalyst composition) as generally disclosed herein with a solvent (e.g., water) to form a flowable paste for the purpose of coating a catalyst substrate. In addition to the catalyst composition, the flowable paste may optionally contain various additional components. The additional components may include, for example, binders as described above herein, additives to control, for example, pH and viscosity of the flowable paste. The additional components may include hydrocarbon storage components (e.g., zeolites), associative thickeners and / or surfactants (including anionic, cationic, nonionic or amphoteric surfactants).An exemplary pH range for the fluid paste is from about 3 to about 6. The addition of acidic or basic species to the fluid paste can be performed to adjust the pH accordingly. For example, in some embodiments, the pH of the fluid paste is adjusted by the addition of aqueous acetic acid.

[0124] The fluid paste can be ground to a reduced particle size to improve particle mixing and the formation of a homogeneous material. Grinding can be carried out in a ball mill, continuous mill or other similar equipment, and the solids content of the fluid paste can be, for example, about 20 to 60% by weight or about 20 to 40% by weight. In some embodiments, the post-grinding fluid paste is characterized by a D90 particle size of about 1 micron to about 40 microns, such as 2 microns to about 20 microns or about 4 microns to about 15 microns. Petition 870260065670, dated 03 / 07 / 2026, p. 49 / 92 41 / 72

[0125] In some embodiments, oxidation catalyst compositions can be applied in the form of one or more washcoats. A washcoat is formed by preparing a fluid paste containing a specified solids content (e.g., about 10 to about 60% by weight) of catalyst composition (or one or more components of the catalyst composition) in a liquid vehicle, which can then be applied to a substrate using any washcoat technique known in the art and dried and calcined to provide a coating layer. If multiple coatings are applied, the substrate can be dried and / or calcined after each washcoat is applied and / or after a series of several desired washcoats are applied. In some embodiments, the catalytic material (or materials) is applied to the substrate as a washcoat.

[0126] A washcoat can be formed by preparing a fluid paste containing a specified solids content (e.g., 30% to 90% by weight) of catalyst material in a liquid vehicle which is then coated onto the substrate (or substrates) and dried to provide a washcoat layer. To coat the wall-flow substrates with the catalyst material in some embodiments, the substrates can be immersed vertically in a portion of the fluid catalyst paste so that the top of the substrate is located just above the surface of the paste. In this way, the fluid paste comes into contact with the inlet face of each honeycomb wall but is prevented from coming into contact with the outlet face of each wall. The sample can be left in the fluid paste for about 30 seconds.The substrate can be removed from the fluid paste, and excess fluid paste can be removed from the wall flow substrate by first allowing it to drain from the channels, then by blowing compressed air (against the direction of fluid paste penetration), and then by pulling a vacuum from the direction of fluid paste penetration. When using this technique, the catalyst fluid paste can permeate the... Petition 870260065670, dated 03 / 07 / 2026, page 50 / 92 42 / 72 substrate walls, but the pores may not be obstructed to the point where undue back pressure accumulates in the finished substrate. As used in this document, the term “permeate,” when used to describe the dispersion of the fluid catalyst paste in the substrate, means that the catalyst composition is dispersed throughout the substrate wall.

[0127] In some embodiments, the coated substrate is dried at an elevated temperature (e.g., 100 to 150 °C) for a period of time (e.g., 1 to 3 hours) and then calcined by heating, for example, at 400 to 600 °C, for about 10 minutes to about 3 hours. After drying and calcining, the final washcoat coating layer can be viewed as essentially solvent-free. After calcining, the catalyst loading can be determined by calculating the difference in weights of the coated and uncoated substrate. As will be evident to those skilled in the art, the catalyst loading can be modified, for example, by altering the rheology of the flow paste. Furthermore, the coating / drying / calcination process can be repeated as needed to produce the coating at the desired loading level or thickness.

[0128] After calcination, the catalyst load obtained by the washcoat technique described above can be determined by calculating the difference between the coated and uncoated weights of the substrate. As will be evident to those skilled in the art, the catalyst load can be modified, for example, by altering the rheology of the flow paste. Furthermore, the coating / drying / calcination process to generate a washcoat layer can be repeated as needed to build up the coating to the desired load level or thickness, meaning that more than one washcoat can be applied.

[0129] In some embodiments, the catalytic coating may comprise one or more coating layers, wherein at least one Petition 870260065670, dated 03 / 07 / 2026, pp. 51 / 92 43 / 72 layer comprises the present catalyst composition or one or more components of the catalyst composition. The catalytic coating may comprise one or more thin adherent coating layers disposed on and adhering to at least a portion of a substrate. The entire coating may comprise the individual coating layers.

[0130] In some embodiments, oxidation catalyst articles may include the use of one or more catalyst layers and combinations of one or more catalyst layers. Catalytic materials may be present on the inlet side of the substrate wall only, on the outlet side only, on both inlet and outlet sides, or the wall itself, in whole or in part, may consist of the catalytic material. The catalytic coating may be on the substrate wall surfaces and / or in the pores of the substrate walls, i.e., “inside” and / or “on” the substrate walls. Thus, the phrase “a washcoat disposed on the substrate” means on any surface, for example, on a wall surface and / or on a pore surface.

[0131] The washcoat (or washcoats) may be applied so that different coating layers may be in direct contact with the substrate. In some embodiments, one or more “sub-coatings” may be present, so that at least a portion of a catalytic coating layer or coating layers is not in direct contact with the substrate, but instead is in contact with the sub-coating. One or more “overcoatings” may also be present, so that at least a portion of the coating layer or layers is not directly exposed to a gas stream or the atmosphere, but instead is in contact with the overcoating.

[0132] In some modalities, the present composition of Petition 870260065670, dated 03 / 07 / 2026, pp. 52 / 92 44 / 72 oxidation catalyst may be in an upper coating layer over a lower coating layer. A catalyst composition may be present in both an upper and a lower layer. Either layer may extend the entire axial length of the substrate; for example, a lower layer may extend the entire axial length of the substrate, and an upper layer may also extend the entire axial length of the substrate over the lower layer. In some embodiments, each of the upper and lower layers may extend from the inlet end or the outlet end.

[0133] For example, both top and bottom coating layers may extend from the same end of the substrate, where the top layer partially or completely overlaps the bottom layer and where the bottom layer extends for a partial or full length of the substrate and where the top layer extends for a partial or full length of the substrate. In some embodiments, a top layer may overlap a portion of a bottom layer. For example, a bottom layer may extend for the entire length of the substrate and the top layer may extend for about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, or about 90% of the substrate length, from both the inlet and outlet ends.

[0134] In some embodiments, a lower layer may extend for about 10%, about 15%, about 25%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85% or about 95% of the substrate length from the inlet end or outlet end and an upper layer may extend for about 10%, about 15%, about 25%, about 30%, about 40%, about 45%, Petition 870260065670, dated 03 / 07 / 2026, page 53 / 92 45 / 72 approximately 50%, approximately 55%, approximately 60%, approximately 65%, approximately 70%, approximately 75%, approximately 80%, approximately 85%, or approximately 95% of the substrate length from the inlet end or outlet end, where at least a portion of the top layer overlaps the bottom layer. This “overlap” zone may, for example, extend from approximately 5% to approximately 80% of the substrate length, for example, approximately 5%, approximately 10%, approximately 20%, approximately 30%, approximately 40%, approximately 50%, approximately 60%, or approximately 70% of the substrate length.

[0135] In some embodiments, the catalytic coating may be advantageously “zoneed,” comprising catalytic layers in zones, i.e., where the catalytic coating contains varying compositions along the axial length of the substrate. This may also be described as “laterally zoned.” For example, one layer may extend from the inlet end to 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 substrate length. Another layer may 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 substrate length. Different coating layers can be adjacent to each other without overlapping.In some embodiments, different layers may overlap a portion of each other, providing a third “intermediate” zone. The intermediate zone may, for example, extend from about 5% to about 80% of the substrate length, for example, about 5%, about 10%, about 20%, about 30%, about 40%, about 50%, about 60% or about 70% of the substrate length.

[0136] Zones can be defined by the relationship of the layers of Petition 870260065670, dated 03 / 07 / 2026, p. 54 / 92 46 / 72 coating. With regard to the different coating layers, there are numerous possible zoning configurations. For example, there may be an upstream zone and a downstream zone, there may be an upstream zone, an intermediate zone and a downstream zone, there may be four different zones, etc. Where two layers are adjacent and do not overlap, there are upstream and downstream zones. Where two layers overlap to some degree, there are upstream, downstream and intermediate zones. Where, for example, one coating layer extends the entire length of the substrate and a different coating layer extends from the outgoing end for a certain length and overlaps a portion of the first coating layer, there are upstream and downstream zones.

[0137] In some embodiments, the first washcoat is disposed over the catalyst substrate from the inlet end to a length of about 10% to about 50% of the total length; and the second washcoat is disposed over the catalyst substrate from the outlet end to a length of about 50% to about 90% of the total length. In some embodiments, the first washcoat is disposed over the catalyst substrate from the outlet end to a length of about 10% to about 50% of the total length; and in which the second washcoat is disposed over the catalyst substrate from the inlet end to a length of about 50% to about 90% of the total length.

[0138] Figures 3a, 3b and 3c show some exemplary coating layer configurations with two coating layers. Substrate walls (200) are shown over which coating layers (201) (top coating) and (202) (bottom coating) are arranged. This is a simplified illustration and, in the case of a porous wall flow substrate, pores and coatings adhering to the substrate are not shown. Petition 870260065670, dated 03 / 07 / 2026, page 55 / 92 47 / 72 pore walls, nor obstructed ends. In Figure 3a, coating layers (201 and 202) each extend the entire length of the substrate with the top layer (201) overlapping the bottom layer (202). The substrate in Figure 3a does not contain a zoned coating configuration. Figure 3b is illustrative of a zoned configuration having a coating layer (202) extending from the outlet for about 50% of the substrate length to form a downstream zone (204) and a coating layer (201) extending from the inlet for about 50% of the substrate length, providing an upstream zone (203).In Figure 3c, the lower coating layer (202) extends from the outlet to about 50% of the substrate length and the upper coating layer (201) extends from the inlet to more than 50% of the length and overlaps a portion of layer (202), providing an upstream zone (203), an intermediate overlap zone (205) and a downstream zone (204). Figures 3a, 3b and 3c may be useful for illustrating SCR catalyst composition coatings on a wall-passing substrate or a continuous flow substrate.

[0139] The loading of catalytic coatings onto a substrate may depend on the substrate properties, such as porosity and wall thickness. For example, the catalyst loading of a wall-flow filter may be lower than the catalyst loadings on a continuous-flow substrate. Catalyzed wall-flow filters are disclosed, for example, in U.S. Patent No. 7,229,597, which is incorporated herein by reference in its entirety. When describing the amount of catalytic metal components or washcoat, or other components of the composition, it may be convenient to use units of component weight per unit volume of catalyst substrate. Therefore, the units, grams per liter (“g / l”) (grams per cubic inch (“g / in3”) and Petition 870260065670, dated 03 / 07 / 2026, page 56 / 92 48 / 72 grams per liter (“g / l”) (grams per cubic foot (“g / ft³”)) are used here to mean the weight of a component per volume of the substrate, which includes the volume of voids in the substrate. Other weight-per-volume units, such as g / l, are also sometimes used. The concentration of a catalyst composition, or any other component, in a substrate refers to the concentration per any three-dimensional section or zone, for example, any cross-section of a substrate or of the entire substrate. The total platinum group metal loading of the composition containing platinum group metal particles (e.g., plurality of Pt particles) in the catalyst substrate, such as a monolithic flow substrate, may, for example, be from about 0.0176 g / l to about 7.06 g / l (0.5 g / ft³ to about 200 g / ft³).

[0140] In some embodiments, an oxidation catalyst article is a diesel oxidation catalyst article. In some embodiments, a plurality of platinum group metal particles are arranged on the substrate in a charge of about 0.176 g / l to about 7.06 g / l (5 g / ft³ to about 200 g / ft³) (for example, about 0.176 g / l to about 1.76 g / l (5 g / ft³ to about 50 g / ft³) and, in certain embodiments, about 0.35 g / l to about 1.76 g / l (10 g / ft³ to about 50 g / ft³) or about 0.35 g / l to about 3.53 g / l (10 g / ft³ to about 100 g / ft³)).

[0141] In some embodiments, an oxidation catalyst article is a catalyzed soot filter article. In some embodiments, a plurality of platinum group metal particles are arranged on the substrate in a loading of about 0.0176 g / l (0.5 g / ft³) to about 1.06 g / l (30 g / ft³), for example, from about 0.0176 g / l (0.5 g / ft³), about 0.035 g / l (1.0 g / ft³), about 0.53 g / l (1.5 g / ft³), about 0.070 g / l (2.0 g / ft³), about 0.088 g / l (2.5 g / ft³), about 0.105 g / l (3.0 g / ft³), or about 0.123 g / l (3.5 g / ft³), to about 0.176 g / l (5 g / ft³), about 0.353 g / l (10 g / ft3), approximately 0.528 g / l (15 g / ft3), about 0.706 g / l (20 g / ft3), about 0.882 g / l (25 g / ft3) Petition 870260065670, dated 03 / 07 / 2026, p. 57 / 92 49 / 72 or 1.059 g / l (30 g / ft3). In some embodiments, a plurality of platinum group metal particles are arranged on the substrate in a charge of about 0.042 g / l (1.2 g / ft3) to about 0.127 g / l (3.6 g / ft3), about 0.052 g / l (1.5 g / ft3) to about 0.095 g / l (2.7 g / ft3), or about 0.060 g / l (1.7 g / ft3) to about 0.077 g / l (2.2 g / ft3).

[0142] Note that these unit volume weights are typically calculated by weighing the catalyst substrate before and after treatment with the catalyst washcoat composition and, as the treatment process involves drying and calcining the catalyst substrate at high temperature, these weights represent an essentially solvent-free catalyst coating, as essentially all the water from the washcoat flow paste has been removed.

[0143] In some embodiments, the level of hydrocarbons, for example, methane or CO, present in the exhaust gas stream is reduced by at least about 30%, or at least about 50%, or at least about 70%, or at least about 75%, or at least about 80%, or at least about 90%, or at least about 95% compared to the level of hydrocarbons or CO present in the exhaust gas stream before contact with the catalyst article. In some embodiments, the temperature for converting hydrocarbons, for example, methane or CO, using the catalyst article described in these embodiments may vary from about 250 °C to about 650 °C, from about 300 °C to about 600 °C, or from about 350 °C to about 550 °C.

[0144] In some embodiments, the efficiency for reducing hydrocarbon and / or CO levels is measured in terms of conversion efficiency. In some embodiments, conversion efficiency is measured as a function of the start-up temperature (i.e., T50). The start-up temperature is the temperature at which the catalyst composition is able to Petition 870260065670, dated 03 / 07 / 2026, pp. 58 / 92 50 / 72 converts 50% of hydrocarbons or carbon monoxide into carbon dioxide and water. Typically, the lower the measured start-up temperature for any given catalyst composition, the more efficient the catalyst composition is at carrying out the catalytic reaction, for example, hydrocarbon conversion.

[0145] In some embodiments, the reduction in NOx level is measured in terms of the NO2 / NOx ratio. In some embodiments, the oxidation catalyst article, after aging at 650 °C for 5 hours, exhibits a NO2 / NOx ratio of about 40 to about 55% when disposed on a 2.54 cm x 7.62 cm (1” x 3”) flow substrate in a platinum group metal feedstock of 0.060 g / l (1.7 g / ft3) and subjected to a feed gas containing 600 ppm NO, 10% O2, 5% CO2, 5% H2O and 33 ppm propane at a temperature of 350 °C and a space velocity of 50,000 per hour.

[0146] In some embodiments, the oxidation catalyst article, after degradation at 550 °C for 5 hours, has a first NO2 / NOx ratio; and after aging at 650 °C for 5 hours, has a second NO2 / NOx ratio; wherein the second NO2 / NOx ratio is at least about 80% of the first NO2 / NOx ratio, when the oxidation catalyst article is arranged on a 2.54 cm x 7.62 cm (1” x 3”) flow substrate in a platinum group metal loading of 0.060 g / l (1.7 g / ft³) and subjected to a feed gas containing 600 ppm NO, 10% O2, 5% CO2, 5% H2O and 33 ppm propane at a temperature of 350 °C and a space velocity of 50,000 per hour. Exhaust Gas Treatment Systems

[0147] In some embodiments, an exhaust gas treatment system comprises an oxidation catalyst article as disclosed in this document. The engine may be, for example, an engine Petition 870260065670, dated 03 / 07 / 2026, p. 59 / 92 51 / 72 a diesel engine operating under combustion conditions with more air than is required for stoichiometric combustion, i.e., lean conditions. In other embodiments, the engine may be a gasoline engine (e.g., lean-burn gasoline engine) or an engine associated with a stationary source (e.g., electricity generators or pumping stations). Exhaust gas treatment systems may contain more than one catalytic article positioned downstream of the engine in fluid communication with the exhaust gas stream. A system may contain, for example, an oxidation catalyst article as described herein (e.g., a diesel oxidation catalyst), a selective catalytic reduction (SCR) catalyst, and / or one or more articles that include a reductant injector, a soot filter, an ammonia oxidation catalyst (AMOx), or a lean NOx trap (LNT). An article containing a reductant injector is a reduction article.A reduction system includes a reducer injector and / or a pump and / or a reservoir, etc. The present treatment system may further comprise a soot filter and / or an ammonia oxidation catalyst. A soot filter may be uncatalyzed or catalyzed, such as a catalyzed soot filter as disclosed herein. For example, the present treatment system may comprise, from upstream to downstream – an article containing a diesel oxidation catalyst, a catalyzed soot filter, a urea injector, an SCR article, and an article containing an AMOx. A lean NOx trap (LNT) may also be included.

[0148] The relative placement of the various catalytic components present within the emission treatment system may vary. In some embodiments, the exhaust gas stream is received in the article (or articles) or treatment system entering at the upstream end and Petition 870260065670, dated 03 / 07 / 2026, pages 60 / 92 52 / 72 exiting at the downstream end. The inlet end of a substrate or article is synonymous with the "upstream" or "front" end. The outlet end is synonymous with the "downstream" or "rear" end. The treatment system may be, for example, downstream of and in fluid communication with an internal combustion engine.

[0149] An exemplary emission treatment system is illustrated in Figure 4, which depicts a schematic representation of an emission treatment system (20). As shown, the emission treatment system may include a plurality of catalyst components in series downstream of an engine (22), such as a lean-burn engine. One or more of the catalyst components may comprise the disclosure oxidation catalyst composition as set out herein (e.g., a diesel oxidation catalyst, a catalyzed soot filter, or both). The disclosure oxidation catalyst composition may be combined with additional catalyst materials and may be placed in various positions relative to the additional catalyst materials.Figure 4 illustrates five catalyst components, (24, 26, 28, 30, 32) in series; however, the total number of catalyst components can vary and five components are just an example.

[0150] For example, Table 1 presents various exhaust gas treatment system configurations. Note that each catalyst can, for example, be connected to the next catalyst via exhaust ducts so that the engine is upstream of catalyst A, which is upstream of catalyst B, which is upstream of catalyst C, which is upstream of catalyst D, which is upstream of catalyst E (when present). The reference to Components A to E in the table can be cross-referenced with the same designations in Figure 4. Petition 870260065670, dated 03 / 07 / 2026, pp. 61 / 92 53 / 72

[0151] The LNT catalyst observed in Table 1 can be any catalyst conventionally used as a NOx trap and may comprise NOx adsorbent compositions that include basic metal oxides (BaO, MgO, CeO2 and the like) and a platinum group metal for catalytic oxidation and reduction of NO (e.g., Pt and Rh).

[0152] The LT-NA catalyst observed in Table 1 can be any catalyst that can adsorb NOx (e.g., NO or NO2) at low temperatures (<250 °C) and release it to the gas stream at high temperatures (>250 °C). The released NOx can be converted to N2 and H2O over a downstream SCR or SCRoF catalyst. For example, an LT-NA catalyst comprises Pd-promoted zeolites or Pd-promoted refractory metal oxides.

[0153] The reference to SCR in the table refers to an SCR catalyst. The reference to SCRoF (or SCR in filter) refers to a particulate or soot filter (e.g., a wall-flow filter), which may include an SCR catalyst composition.

[0154] The reference to AMOx in the table refers to an ammonia oxidation catalyst, which may be provided, for example, downstream of an oxidation catalyst to remove any ammonia that runs off from the exhaust gas treatment system. In some embodiments, the AMOx catalyst may comprise a platinum group metal component. In some embodiments, the AMOx catalyst may comprise a lower coating with platinum group metal and an upper coating with SCR functionality.

[0155] As recognized by one skilled in the art, in the configurations listed in Table 1, any one or more of the components A, B, C, D, or E may be arranged in a particle filter, such as a wall-flow filter, or a continuous-flow alveolar substrate. In Petition 870260065670, dated 03 / 07 / 2026, pages 62 / 92 54 / 72 In some embodiments, an engine exhaust system comprises one or more catalyst compositions mounted in a position close to the engine (in a coupled position, CC), with additional catalyst compositions in a position under the vehicle body (in an under-floor position, UF). In some embodiments, the exhaust gas treatment system may further comprise a urea injection component. Table 1. Example Configurations of a Treatment System Exhaust Gas Component A Component B Component C Component D Component E Optional SCR AMOx diesel oxidation catalyst - Optional SCRoF AMOx diesel oxidation catalyst - Optional SCRoF AMOx diesel oxidation catalyst - Optional SCR AMOx diesel oxidation catalyst - Optional SCR AMOx catalyzed soot filter - Optional LNT Optional SCR AMOx catalyzed soot filter - Optional LNT Method for Treating an Exhaust Gas Stream

[0156] In another aspect, a method is provided for treating an engine exhaust gas stream comprising hydrocarbons and / or carbon monoxide (CO) and / or NOx. In some embodiments, the method comprises bringing the exhaust gas stream into contact with the catalytic article of this disclosure or the emission treatment system of this disclosure.

[0157] In some forms, hydrocarbons and CO are present Petition 870260065670, dated 03 / 07 / 2026, pp. 63 / 92 55 / 72 in the exhaust gas stream of any engine can be converted into carbon dioxide (CO2) and water. For example, the hydrocarbons present in an engine exhaust gas stream may comprise C1-C6 hydrocarbons (i.e., lower hydrocarbons), such as methane, although higher hydrocarbons (greater than C6) may also be present. In some embodiments, the method comprises placing the gas stream in contact with the catalytic article or exhaust gas treatment system of the present disclosure, for a time and temperature sufficient to reduce the levels of CO and / or hydrocarbons in the gas stream.

[0158] In some embodiments, NOx species, such as NO, present in the exhaust gas stream of an engine can be converted (oxidized) to NO2. In some embodiments, the method comprises bringing the gas stream into contact with the catalytic article or exhaust gas treatment system of the present disclosure for a time and at a temperature sufficient to oxidize at least a portion of the NO present in the gas stream to NO2.

[0159] The present articles, systems and methods may be suitable for treating exhaust gas streams from mobile emission sources, such as trucks and automobiles. In some embodiments, articles, systems and methods are also suitable for treating exhaust streams from stationary sources, such as power plants.

[0160] Some additional exemplary modalities include, without limitation: 1. An oxidation catalyst composition, wherein the composition comprises a plurality of platinum group metal particles having a multimodal particle size distribution, wherein the plurality of platinum group metal particles comprises: a Petition 870260065670, dated 03 / 07 / 2026, pp. 64 / 92 56 / 72 first population of platinum group metal particles having a particle size range from about 0.5 nm to about 3 nm; and a second population of platinum group metal particles with a particle size range from about 4 nm to about 15 nm; 2. The oxidation catalyst composition of embodiment 1, wherein the first population of platinum group metal particles has a particle size distribution characterized by an average particle size of about 1 nm and at least about 80% of the first population of platinum group metal particles have a particle size within about 1 nm of the average particle size; 3. The oxidation catalyst composition of embodiment 1 or 2, wherein the second population of platinum group metal particles has a particle size distribution characterized by an average particle size of about 6 nm and at least about 80% of the second population of platinum group metal particles have a particle size within about 2 nm of the average particle size; 4. The oxidation catalyst composition of any of the embodiments 1 to 3, wherein the weight ratio between the first population of platinum group metal particles and the second population of platinum group metal particles is from about 10:90 to about 90:10; 5. The oxidation catalyst composition of any of the embodiments 1 to 4, wherein the weight ratio between the first population of platinum group metal particles and the second population of platinum group metal particles is from about 50:50 to about 90:10; 6. The oxidation catalyst composition of any of the embodiments 1 to 5, wherein the weight ratio between the first population of platinum group metal particles and the second population of platinum group metal particles is from about 50:50 to about 75:25; Petition 870260065670, dated 03 / 07 / 2026, pages 65 / 92 57 / 72 7. The composition of the oxidation catalyst of any of the embodiments 1 to 6, in which the plurality of platinum group metal particles has an average particle size of about 3 nm to about 12 nm; 8. The composition of the oxidation catalyst of any of the embodiments 1 to 7, in which the plurality of platinum group metal particles has an average particle size of about 3 nm to about 10 nm; about 3 nm to about 8 nm; about 3 nm to about 6 nm; or about 3 nm to about 5 nm; 9. An oxidation catalyst composition of any of the embodiments 1 to 8, in which at least about 90% of the platinum group metal from one or more of the first and second populations of platinum group metal particles are in the fully reduced form; 10. An oxidation catalyst composition of any of embodiments 1 to 9, wherein the platinum group metal of one or more of the first and second populations of platinum group metal particles comprises platinum, palladium, ruthenium, rhodium, iridium, or a combination thereof; 11. An oxidation catalyst composition of any of the embodiments 1 to 10, wherein the platinum group metal of one or more of the first and second populations of platinum group metal particles comprises platinum, palladium, or a combination thereof; 12. The oxidation catalyst composition of any of the embodiments 1 to 11, in which the platinum group metal of one or more of the first and second populations of platinum group metal particles is platinum; 13. An oxidation catalyst composition of any of the embodiments 1 to 12, further comprising at least one refractory metal oxide support; Petition 870260065670, dated 03 / 07 / 2026, pages 66 / 92 58 / 72 14. The oxidation catalyst composition of embodiment 13, wherein at least one refractory metal oxide support comprises alumina (AbO3), silica (SiO2), zirconia (ZrO2), titania (TiO2), ceria (CeO2) or combinations thereof; 15. The oxidation catalyst composition of embodiment 13 or 14, wherein at least one refractory metal oxide support comprises Al2O3 doped with SiO2, TiO2 doped with SiO2 or ZrO2 doped with SiO2; 16. The oxidation catalyst composition of any of the embodiments 13 to 15, wherein at least one refractory metal oxide support comprises AbO3 doped with 1 to 10% SO2, TO2 doped with 1 to 20% SiO2 or ZrO2 doped with 1 to 30% SO2; 17. An oxidation catalyst composition of any of the embodiments 13 to 16, wherein the first population of platinum group metal particles and the second population of platinum group metal particles are both dispersed on the same refractory metal oxide support; 18. The oxidation catalyst composition of any of the embodiments 14 to 17, wherein the first population of platinum group metal particles and the second population of platinum group metal particles are each dispersed on separate refractory metal oxide supports, wherein the first population of platinum group metal particles is dispersed on a first refractory metal oxide support and the second population of platinum group metal particles is dispersed on a second refractory metal oxide support, wherein the first refractory metal oxide support and the second refractory metal oxide support are each independently selected; 19. The oxidation catalyst composition of embodiment 18, wherein the first refractory metal oxide support and the second refractory metal oxide support both comprise the same support material of Petition 870260065670, dated 03 / 07 / 2026, pages 67 / 92 59 / 72 refractory metal oxide; 20. The oxidation catalyst composition of embodiment 19, wherein the refractory metal oxide support material comprises TO2 or TiO2 doped with SiO2; 21. An oxidation catalyst article comprising a substrate having an inlet end and an outlet end defining a total length and a catalytic coating comprising the oxidation catalyst composition of any of the embodiments 1 to 20 disposed in at least a portion thereof; 22. The oxidation catalyst article of embodiment 21, in which the substrate is a continuous flow monolith or a wall flow filter; 23. The oxidation catalyst article of embodiment 21 or 22, wherein the oxidation catalyst article is a diesel oxidation catalyst article; 24. The diesel oxidation catalyst article of embodiment 23, in which the plurality of PGM particles are arranged on the substrate in a charge of about 0.176 g / l to about 7.062 g / l (5 g / ft3 to about 200 g / ft3); 25. The oxidation catalyst article of embodiment 21 or 22, wherein the oxidation catalyst article is a catalyzed soot filter article; 26. The catalyzed soot filter article of embodiment 25, in which the plurality of PGM particles are arranged on the substrate with a charge of about 0.0176 g / l to about 1.059 g / l (0.5 g / ft3 to about 30 g / ft3); 27. The oxidation catalyst article of any of the embodiments 21 to 26, wherein, after aging the oxidation catalyst article at 650 °C for 5 hours, the oxidation catalyst article exhibits a NO2 / NOx ratio of about 40% to about 55% when subjected to a gas. Petition 870260065670, dated 03 / 07 / 2026, pp. 68 / 92 60 / 72 feed containing 600 ppm of NO, 10% O2, 5% CO2, 5% H2O and 33 ppm of propane at a temperature of 350 °C and a space velocity of 50,000 per hour; 28. An oxidation catalyst article of any of the embodiments 21 to 27, wherein after degradation at 550 °C for 5 hours, the oxidation catalyst article has a first NO2 / NOx ratio and after aging at 650 °C for 5 hours, the oxidation catalyst article has a second NO2 / NOx ratio; wherein the second NO2 / NOx ratio is at least about 80% of the first NO2 / NOx ratio; and wherein the first and second NO2 / NOx ratios are determined by subjecting the oxidation catalyst article to a feed gas containing 600 ppm NO, 10% O2, 5% CO2, 5% H2O and 33 ppm propane at a temperature of 350 °C and a space velocity of 50,000 per hour; 29. An exhaust gas treatment system comprising the oxidation catalyst article of any of claims 21 to 28, wherein the oxidation catalyst article is downstream of and in fluid communication with an internal combustion engine; 30. The exhaust gas treatment system of embodiment 29, further comprising one or more catalytic articles selected from a urea injector, a selective catalytic reduction (SCR) catalyst, an ammonia oxidation catalyst (AMOx), a low-temperature NOx adsorbent (LT-NA), and a lean NOx trap (LNT); 31. A method for treating an exhaust gas stream comprising hydrocarbons, carbon monoxide and / or NOx, wherein the method comprises passing the exhaust gas stream through the catalytic article, of any of the embodiments 21 to 28, or the exhaust gas treatment system, of embodiment 29 or 30; and 32. The oxidation catalyst article of embodiment 18, in which Petition 870260065670, dated 03 / 07 / 2026, pp. 69 / 92 61 / 72 a plurality of platinum group metal particles is arranged on the substrate with a charge of about 0.0176 g / l to about 0.176 g / l (0.5 g / ft3 to about 5 g / ft3).

[0161] It will be readily apparent to one skilled in the relevant art that appropriate modifications and adaptations to the compositions, methods, and applications described herein can be made without departing from the scope of any embodiments or aspects thereof. The compositions and methods provided are exemplary and are not intended to limit the scope of the claimed embodiments. All the various exemplary embodiments, aspects, and options disclosed herein may be combined in all variations. The scope of the compositions, formulations, methods, and processes described herein includes all actual or potential combinations of embodiments, aspects, options, examples, and preferences herein. All patents and publications cited herein are incorporated by reference for the specific teachings thereof, as noted, unless other specific statements of incorporation are specifically provided. Examples

[0162] The following examples are for illustrative purposes only and are not intended to limit the scope of the disclosure. Unless otherwise noted, all parts and percentages are by weight and all percentages by weight are expressed on a dry basis, meaning excluding water content, unless otherwise indicated. Examples 1a AE

[0163] In Examples 1A to E, a colloidal Pt suspension was prepared, dispersed on a titania support material, and milled. Subsequently, catalyzed soot filter articles were prepared with a Pt loading of 0.042 g / l to 0.127 g / l (1.2 g / ft³ to 3.6 g / ft³) coating a filter substrate. Petition 870260065670, dated 03 / 07 / 2026, pp. 70 / 92 62 / 72 wall flux soot with Pt supported on resulting titanium.

[0164] Specifically, octanol (1 g) was added to water (820 g) under gentle stirring. The Titania support material (310 g) was gradually added to the water / octanol mixture with stirring. Dispersant (4 g) was added to facilitate the dispersion of the support in the aqueous phase. Subsequently, tartaric acid (2.3 g) was added to lower the pH to 3.8. Mixing was then continued for 30 minutes. The resulting well-dispersed fluid paste of support material was transferred to a mill for particle size reduction to a D90 of approximately 5 microns. The milled fluid paste was transferred to a clean container and an aqueous portion of pre-formed Pt material prepared according to US2017 / 0304805 and US2019 / 001578 was added at various target Pt charges (measured in g / l (g / ft3)). The average size of the Pt particles was 5.9 nm, with a particle size range of 4 nm to 15 nm.The resulting fluid paste was then coated onto a wall-flow filter substrate with a dry washcoat gain of 9.15 g / l (0.15 g / in3), followed by drying at 120 °C for 2 hours and calcination at 590 °C for one hour. The Pt loadings for each example are given in Table 2. Table 2: Pt Loads of Examples 1a AE Example no. Pt (g / l (g / ft3)) 1A 0.042 (1.2) 1B 0.0152 (1.5) 1C 0.063 (1.8) 1D 0.095 (2.7) 1E 0.127 (3.6) Example 2

[0165] In Example 2, a titanium support material was impregnated with a Pt solution and milled. Subsequently, a catalyzed soot filter article was prepared with a Pt loading of 0.099 g / l (2.8 g / ft3) coating a wall-flow soot filter substrate with the support. Petition 870260065670, dated 03 / 07 / 2026, pp. 71 / 92 63 / 72 titanium impregnated with milled Pt.

[0166] Specifically, the titania support material (255 g) was impregnated with a solution of tetra-amine platinum(II) complex (13.2 g) by adding dropwise to the dry powder under mixing. The Pt-impregnated support mixture was then added to water (260 g) to form a well-dispersed flowable paste. A dispersant (up to 1.5% of the solid material) was added if necessary. The pH of the flowable paste was adjusted to 4.2 using tartaric acid. The well-dispersed flowable paste was fed into a mill for particle size reduction to a D90 of approximately 5 microns. The resulting flowable paste was then coated onto wall-flow filter substrates with a dry washcoat gain of 9.153 g / l (0.15 g / in3). This was followed by drying at 120 °C for 2 hours and calcination at 590 °C for one hour. The average particle size of Pt was 1.3 nm, with a particle size range of 0.5 nm to 3 nm. Examples 3 to 6

[0167] The catalyst compositions of Examples 3 to 6 were prepared by impregnating a titanium support material with a Pt solution, followed by removing Pt particles from a colloidal Pt suspension in the impregnated titanium support material using the procedures below. The ratio between impregnated Pt (referred to here as “Pt A”) and deposited colloidal Pt (referred to here as “Pt B”) for the composition of each Example is given in Table 3.

[0168] Examples 3 to 5 were prepared by impregnating a titania support material with a Pt solution. The resulting material was ground and used to prepare a fluid paste with the pH adjusted to less than 5. Colloidal Pt was then dispersed on the titania support.

[0169] Specifically, the titanium support material (260 g) was impregnated with a solution of tetra-amine platinum(II) complex (3,4, 6,7 and 10,1 Petition 870260065670, dated 03 / 07 / 2026, pages 72 / 92 64 / 72 g, respectively for Examples 3 to 5). The Pt solution was added as a moist mist to the dry powder at a medium mixing rate in a closed container. After the addition of the Pt solution was complete, mixing continued for 30 minutes. A fluid paste was prepared by mixing the impregnated support with water (575 g), dispersant (3.5 g), and octanol (1 g) with stirring. Subsequently, tartaric acid (2.1 g) was added to lower the pH to 3.9, followed by mixing for 30 minutes. The well-dispersed mixture was then fed into a mill and the particle size was reduced to a D90 of approximately 5 microns. The milled fluid paste was transferred to a clean container and an aqueous portion of pre-formed Pt material prepared in accordance with documents US2017 / 0304805 and US2019 / 001578 was added at 90 g, 60 g and 30 g for Examples 3, 4 and 5, respectively, to achieve the desired Pt charges (measured in g / l (g / ft3)).Silica sol binder (10.5 g) was added and the resulting flow paste was then coated onto wall-flow filter substrates with a dry washcoat gain of 9.153 g / l (0.15 g / in3). This was followed by drying at 120 °C for 2 hours and calcination at 590 °C for one hour.

[0170] Example 6 was prepared by impregnating a titanium support material with a Pt solution as follows. Water (680 g), octanol (1 g), and dispersant (3.3 g) were thoroughly mixed under stirring for 30 minutes. The pH of the mixture was adjusted to 6.5 using monoethylamine. A solution of tetra-amine platinum(II) complex (2.3 g) was added to the mixture, and the pH was adjusted to 4.3 with tartaric acid. Colloidal Pt (60 g) was then added under stirring. The well-dispersed mixture was fed into a mill, and the particle size was reduced to a D90 of about 5 microns. The milled flow paste was transferred to a clean container, silica sol binder (8.2 g) was added, and the resulting flow paste was then coated in Petition 870260065670, dated 03 / 07 / 2026, pp. 73 / 92 65 / 72 wall-flow filter substrates with a dry washcoat gain of 9.153 g / l 0.099 g / l (0.15 g / in3a 2.8 g / ft3) Pt loading. This was followed by drying at 120 °C for 2 hours and calcination at 590 °C for one hour. Examples 7 to 12

[0171] The catalyst compositions of Examples 7 to 12 were prepared by impregnating a titanium support material with a Pt solution and dispersing colloidal Pt on a separate titanium support using the procedures below. The ratio of Pt A to Pt B for the composition of each Example is given in Table 3. Example 7

[0172] The platinum tetraamine complex solution (4.4 g) was diluted with 110 g of water and added as a moist mist to the dry titania support material powder (200 g) at a medium mixing rate in a closed container. After the addition of the Pt solution was complete, mixing continued for 30 minutes. Water (365 g), octanol (0.6 g), and dispersant (2.6 g) were thoroughly mixed under stirring, and the moist Pt-impregnated support material was added to the mixture under stirring. The pH was adjusted to 3.9 with tartaric acid (1 g), and the mixture was stirred for 30 minutes. The well-dispersed mixture was loaded into a mill, and the particle size was reduced to a D90 of approximately 5 microns.

[0173] Separately, the support material (133.5 g), water for forming a fluid paste (295 g), and the dispersant (1.65 g) were mixed under stirring for 30 minutes. Tartaric acid was added to lower the pH to 3.9, and the fluid paste was ground to a D90 of about 5 microns. To this fluid paste was added pre-formed platinum group metal material (118 g) prepared in accordance with US2017 / 0304805 and US2019 / 001578 at a target platinum group metal loading of 0.529 g / l (15 g / ft3). Petition 870260065670, dated 03 / 07 / 2026, pp. 74 / 92 66 / 72

[0174] The two separate fluid pastes were combined and silica sol binder (19.5 g) was added. The resulting fluid paste was then coated onto continuous flow substrates with a dry washcoat gain of 51.87 g / l (0.85 g / in3), followed by drying at 120 °C for 2 hours and then calcination at 590 °C for one hour, as described above. Example 8

[0175] The platinum tetraamine complex solution (10.8 g) was diluted with 130 g of water and added as a moist mist to a dry powder of support material (205 g) at an average mixing rate in a closed container. After the addition of the Pt solution was complete, mixing continued for 30 minutes. Water (395 g), octanol (0.6 g), and dispersant (2.6 g) were thoroughly mixed under stirring, and the moist Pt-impregnated support material was added to the mixture under stirring. The pH was adjusted to 4.7 with tartaric acid (1.8 g), and the mixture was stirred for 30 minutes. The well-dispersed mixture was fed into a mill, and the particle size was reduced to a D90 of approximately 5 microns.

[0176] Separately, the support material (205 g), water for forming a fluid paste (480 g), and dispersant (2.6 g) were mixed under stirring for 30 minutes. Tartaric acid (1 g) was added to lower the pH to 4.1, and the fluid paste was ground to a D90 of about 5 microns. To this fluid paste was added pre-formed platinum group metal material (96 g) prepared according to US2017 / 0304805 and US2019 / 001578 at a target platinum group metal loading of 0.529 g / l (15 g / ft3).

[0177] The two separate fluid pastes were combined and silica sol binder (19.5 g) was added. The resulting fluid paste was then coated onto continuous flow substrates with a dry washcoat gain of 51.87 g / l (0.85 g / in3), followed by drying at 120 °C for 2 hours and then calcination at 590 °C for one hour, as described above. Petition 870260065670, dated 03 / 07 / 2026, pp. 75 / 92 67 / 72 Example 9

[0178] The platinum tetraamine complex solution (13.4 g) was diluted with 155 g of water and added as a moist mist to a dry powder of support material (260 g) at a medium mixing rate in a closed container. After the addition of the Pt solution was complete, mixing continued for 30 minutes. The moist Pt-impregnated support powder was spread on a ceramic tray and calcined in a furnace at 500 °C for 5 hours. Water (640 g), octanol (0.8 g), and dispersant (3.2 g) were thoroughly mixed under stirring, and the calcined Pt-impregnated support material was added to the mixture under stirring. The pH was adjusted to 4.7 with tartaric acid (1.8 g), followed by stirring for 30 minutes. The well-dispersed mixture was loaded into a mill, and the particle size was reduced to a D90 of approximately 5 microns.

[0179] Separately, the support material (260 g), water for fluid paste formation (610 g), and dispersant (3.3 g) were mixed under stirring for 30 minutes. Tartaric acid (1 g) was added to lower the pH to 4.1, and the fluid paste was milled to a D90 of approximately 5 microns. To this fluid paste was added pre-formed platinum group metal material (120 g) prepared in accordance with US2017 / 0304805 and US2019 / 001578) at a target platinum group metal loading of 0.529 g / l (15 g / ft3). The two separate fluid pastes were combined, and silica sol binder (23.2 g) was added. The resulting flowable paste was then coated onto continuous flow substrates with a dry washcoat gain of 51.87 g / l (0.85 g / in3). This was followed by drying at 120 °C for 2 hours and then calcination at 590 °C for one hour. Example 10

[0180] A solution of platinum tetraamine complex (10.8 g) diluted with 120 g of water was added as a moist mist to a dry powder of supporting material (200 g) at an average mixing rate in a container. Petition 870260065670, dated 03 / 07 / 2026, pp. 76 / 92 68 / 72 closed. After the addition of the Pt solution was complete, mixing continued for 30 minutes. The moist Pt-impregnated support powder was spread on a ceramic tray and calcined in an oven at 550 °C for 5 hours. Water (440 g), octanol (0.6 g), and dispersant (2.5 g) were thoroughly mixed under stirring, and the calcined Pt-impregnated support material was added to the mixture under stirring. The pH was adjusted to 4.7 with tartaric acid (1.8 g), followed by stirring for 30 minutes. The well-dispersed mixture was loaded into a mill, and the particle size was reduced to a D90 of approximately 5 microns.

[0181] Separately, the support material (200 g), water for flowable paste formation (460 g), and dispersant (2.6 g) were mixed under stirring for 30 minutes. Tartaric acid (2.1 g) was added to lower the pH to 3.5, and the flowable paste was milled to a D90 of approximately 5 microns. To this flowable paste was added pre-formed platinum group metal material (93 g) prepared in accordance with US2017 / 0304805 and US2019 / 001578) at a target platinum group metal loading of 0.529 g / l (15 g / ft3). The two separate pastes were combined, and silica sol binder (18.2 g) was added. The resulting flowable paste was then coated onto continuous flow substrates with a dry washcoat gain of 51.87 g / l (0.85 g / in3). This was followed by drying at 120 °C for 2 hours and then calcination at 590 °C for one hour. Example 11

[0182] The platinum tetraamine complex solution (10.8 g) was diluted with 120 g of water and added as a moist mist to a dry powder of support material (200 g) at an average mixing rate in a closed container. After the addition of the Pt solution was complete, mixing continued for 30 minutes. The support powder impregnated with moist Pt was spread on a ceramic tray and calcined in an oven at 600 °C for 5 hours. Water (495 g), octanol (0.6 g) and dispersant (2.6 g) were thoroughly mixed under stirring and the Petition 870260065670, dated 03 / 07 / 2026, pp. 77 / 92 69 / 72 support material impregnated with calcined Pt was added to the mixture under stirring for 30 minutes.

[0183] Separately, the support material (200 g), water for flowable paste formation (520 g), and dispersant (2.6 g) were mixed under stirring for 30 minutes. Tartaric acid (2.1 g) was added to lower the pH to 3.8, and the flowable paste was milled to a D90 of approximately 5 microns. To this flowable paste was added pre-formed platinum group metal material (95 g) prepared according to US2017 / 0304805 and US2019 / 001578 at a target platinum group metal loading of 0.529 g / l (15 g / ft3). The two separate pastes were combined, and silica sol binder (18.2 g) was added. The resulting flowable paste was then coated onto continuous flow substrates with a dry washcoat gain of 51.87 g / l (0.85 g / in3). This was followed by drying at 120 °C for 2 hours and then calcination at 590 °C for one hour. Example 12

[0184] The platinum tetraamine complex solution (15.7 g) was diluted with 185 g of water and added as a wet mist to a dry powder of support material (303.4 g) at an average mixing rate in a closed container. After the addition of the Pt solution was complete, mixing continued for 30 minutes. The batch was divided into three equal parts, and each part of wet Pt-impregnated support powder was spread on a separate ceramic tray. The wet powders were separately calcined in a furnace at 500 °C for 5 hours, 550 °C for 5 hours, and 600 °C for 5 hours, respectively. After calcination, all powders were combined into a single batch and thoroughly mixed. Water (650 g), octanol (0.9 g), and dispersant (3.9 g) were thoroughly mixed under stirring, and the calcined Pt-impregnated support material was added to the mixture under stirring for 30 minutes. The mixture was loaded into a mill and the particle size was measured. Petition 870260065670, dated 03 / 07 / 2026, pp. 78 / 92 70 / 72 was reduced to a D90 of approximately 5 microns.

[0185] Separately, the support material (303.2 g), water for flowable paste formation (600 g), and dispersant (3.9 g) were mixed under stirring for 30 minutes. Tartaric acid (1.3 g) was added to lower the pH to 4.1, and the flowable paste was milled to a D90 of approximately 5 microns. To this flowable paste was added pre-formed platinum group metal material (140 g) prepared in accordance with US2017 / 0304805 and US2019 / 001578) at a target platinum group metal loading of 0.529 g / l (15 g / ft3). The two separate flowable pastes were combined, and silica sol binder (19.4 g) was added. The resulting flowable paste was then coated onto continuous flow substrates with a dry washcoat gain of 51.87 g / l (0.85 g / in3) followed by drying at 120 °C for 2 hours and then calcination at 590 °C for one hour. Table 3: Pt A / B Ratios for Compositions from Examples 3 to 12 Example # Ratio Point A: Point B 3 25:75 4 50:50 5 75:25 6 50:50 7 25:75 8 50:50 9 50:50 10 50:50 11 50:50 12 50:50 Example 13. Diesel Oxidation Catalyst Coating Articles

[0186] Articles according to Examples 1 to 11 in diesel oxidation catalyst coating configurations were evaluated for NO2 production degradation at 300 °C (Figure 5). Core samples from each article were tested in a laboratory reactor employing a synthetic gas mixture comprising 10% oxygen, 5% carbon dioxide, 100 ppm CO, 600 ppm NO, 100 ppm hydrocarbon, 5% H2O, with nitrogen balance. Petition 870260065670, dated 03 / 07 / 2026, pp. 79 / 92 71 / 72 Each sample was tested fresh, after degreening, and after aging at 600 °C for 20 hours. The oxidation stability of NO against aging was the main focus, and the decrease in activity for converting NO to NO2 was calculated as the NO2 production degradation. Example 3 showed the lowest NO2 production degradation, followed by Examples 2, 7, 8, 6, and 10. Example 14. Results for Catalyzed (Aged) Soot Filter Articles

[0187] Articles according to Examples 3 and 10 in catalyzed soot filter coating configurations were aged at 550 °C for 100 hours, then evaluated for NO2 loss across a temperature range of 200 to 350 °C. Stable NO2 production was observed for both articles, showing a 5 to 8% loss of NO2 production with aging (Figure 6 and Table 4). Table 4: Loss of NO2 Production with Aging Example of platinum group metal loading: % NO2 loss at 200C % NO2 loss at 250C % NO2 loss at 300C % NO2 loss at 350C 3 0.060 g / l (1.7 g / ft3) 7.50 8 8 5 10 0.077 g / l (2.2 g / ft3) 4 7.8 5 4.8 Example 15. % Oxidation of NO After Aging

[0188] Catalyzed soot filter articles (Examples 1A to E, 3 and 10) were evaluated for % NO oxidation at 250 °C, 300 °C and 350 °C after aging at 650 °C for 5 hours. Example 3 yielded the highest NO2 production after aging (31 to 44%), while Example 10 was comparable to Example 1E (23 to 37%), which had a platinum group metal loading of 0.0176 g / l (0.5 g / ft3) higher (Figure 7). The change in maximum NO oxidation for the degreening-passed versus aged catalyst articles is illustrated in Figure 8, which demonstrated that Examples 3 and 10 produced almost unchanged NO2 after aging. Petition 870260065670, dated 03 / 07 / 2026, pages 80 / 92 72 / 72 Example 16. Extraction of CO and Hydrocarbons

[0189] Catalyzed soot filter articles (Examples 1A to E, 3, and 10) were evaluated for hydrocarbon T50 and carbon monoxide (CO) start-up temperatures after passing through degreening and aging. Examples 3 and 10 showed only a small increase in T50 of hydrocarbons and CO after aging (Figure 9). Example 17. Engine Test Results for Full-Size Catalyzed Soot Filter Articles

[0190] Full-size catalyzed soot filter articles (catalyst compositions coated on wall-flow substrates 26.67 cm (10.5”) in diameter by 25.4 cm (10”) in length) were prepared and evaluated under engine test conditions. The full-size catalyzed soot filter article of Example 1 was prepared according to Example 1 with a Pt loading of 0.060 g / l (1.7 g / ft3). The full-size catalyzed soot filter articles of Examples 3 and 10 were prepared according to Examples 3 and 10 with a Pt loading of 0.060 and 0.077 g / l (1.7 and 2.2 g / ft3), respectively.The change in NO oxidation performance for samples that underwent degreening and were aged over 6 engine test cycles is provided in Figure 10, which illustrates that the catalyzed soot filter article from Example 10 in full size performed best, followed by the catalyzed soot filter article from Example 3 in full size, and finally the catalyzed soot filter article from Example 1 in full size. Petition 870260065670, dated 03 / 07 / 2026, pp. 81 / 92

Claims

1 / 5 Claims 1. OXIDATION CATALYST COMPOSITION, characterized by comprising a plurality of platinum group metal particles having a multimodal particle size distribution, wherein the plurality of platinum group metal particles comprises: a first population of platinum group metal particles with a particle size range from 0.5 nm to 3 nm, wherein the first population of platinum group metal particles has a particle size distribution defined by an average particle size of 1 nm, and at least 80% of the first population of platinum group metal particles has a particle size within 1 nm of the average particle size;and a second population of platinum group metal particles with a particle size range from 4 nm to 15 nm, wherein the second population of platinum group metal particles has a particle size distribution defined by an average particle size of 6 nm and at least 80% of the second population of platinum group metal particles has a particle size within 2 nm of the average particle size, and the weight ratio of the first population of platinum group metal particles to the second population of platinum group metal particles is 10:90 to 90:10, 50:50 to 90:10, or 50:50 to 75:

25.

2. COMPOSITION, according to claim 1, characterized in that the plurality of platinum group metal particles have an average particle size of 3 to 12 nm, 3 nm to 10 nm; 3 nm to 8 nm; 3 nm to 6 nm; or 3 nm to 5 nm.

3. COMPOSITION, according to any one of claims 1 to 2, characterized in that at least 90% or more of the platinum group metal from one or more of the first and second populations of platinum group metal particles is in the fully reduced form.

4. COMPOSITION, according to any one of claims 1 to 3, characterized by the platinum group metal of one or more of the first and second populations of platinum group metal particles comprising platinum, palladium, ruthenium, rhodium, iridium or a combination thereof.

5. COMPOSITION, according to any one of claims 1 to 4, characterized in that one or more of the first and second populations of platinum group metal particles are platinum.

6. COMPOSITION, according to any one of claims 1 to 5, characterized by further comprising at least one refractory metal oxide support.

7. COMPOSITION, according to claim 6, characterized in that said at least one refractory metal oxide support comprises alumina (AbOa), silica (SiO2), zirconia (ZrO2), titania (TiO2), ceria (CeO2) or combinations thereof.

8. COMPOSITION, according to any one of claims 6 to 7, characterized in that said at least one refractory metal oxide support comprises AbOa doped with 1 to 10% SiO2, TiO2 doped with 1 to 20% SiO2, or ZrO2 doped with 1 to 30% SiO2.

9. COMPOSITION, according to any one of claims 6 to 8, characterized in that the first population of platinum group metal particles and the second population of platinum group metal particles are both dispersed in the same refractory metal oxide support.

10. COMPOSITION, according to any one of claims 6 to 8, characterized in that the first population of platinum group metal particles and the second population of platinum group metal particles are each dispersed on separate refractory metal oxide supports, wherein the first population of platinum group metal particles is dispersed on a first refractory metal oxide support, and the second population of platinum group metal particles is dispersed on a second refractory metal oxide support, wherein the first refractory metal oxide support and the second refractory metal oxide support are each independently selected.

11. COMPOSITION, according to claim 10, characterized in that the first refractory metal oxide support and the second refractory metal oxide support both comprise the same refractory metal oxide support material.

12. COMPOSITION, according to claim 11, characterized in that the refractory metal oxide support material comprises TiO2 or TiO2 doped with SiO2.

13. OXIDATION CATALYST ARTICLE, characterized by comprising a substrate with an inlet end and an outlet end defining a total length, and a catalytic coating comprising the oxidation catalyst composition, as defined in any one of claims 1 to 12, disposed in at least a portion thereof.

14. ARTICLE, according to claim 13, characterized in that the substrate is a continuous flow monolith or a wall flow filter.

15. ARTICLE, according to any one of claims 13 to 14, characterized in being a diesel oxidation catalyst article or a catalyzed soot filter article.

16. DIESEL OXIDATION CATALYST ARTICLE, as defined in claim 15, characterized by the plurality of platinum group metal particles being arranged on the substrate with a charge of 0.176 g / l to 7.062 g / l (5 g / ft3 to 200 g / ft3).

17. CATALYZED SOOT FILTER ARTICLE, as defined in claim 15, characterized by a plurality of platinum group metal particles being arranged on the substrate with a charge of 0.0176 g / l to 1.059 g / l (0.5 g / ft3 to 30 g / ft3).

18. ARTICLE, according to claim 15, characterized by a plurality of platinum group metal particles being arranged on the substrate with a charge of 0.0176 g / l 0.176 g / l (0.5 g / ft3 to 5 g / ft3).

19. ARTICLE, according to any one of claims 13 to 18, characterized in that, after aging the oxidation catalyst article at 650 °C for 5 hours, the oxidation catalyst article exhibits a NO2 / NOx ratio of 40% to 55% when the substrate is a continuous flow substrate of 2.54 cm x 7.62 cm (1” x 3”), the oxidation catalyst article has a platinum group metal loading of 0.06 g / l (1.7 g / ft3), and the oxidation catalyst article is subjected to a feed gas containing 600 ppm NO, 10% O2, 5% CO2, 5% H2O and 33 ppm propane at a temperature of 350 °C and a space velocity of 50,000 per hour.

20. ARTICLE, according to any one of claims 13 to 19, characterized in that, after the oxidation catalyst article undergoes degreening at 550 °C for 5 hours, said oxidation catalyst article has a first NO2 / NOx ratio and, after aging the oxidation catalyst article at 650 °C for 5 hours, said oxidation catalyst article has a second NO2 / NOx ratio; wherein the second NO2 / NOx ratio is at least 80% of the first NO2 / NOx ratio; and wherein the first and second NO2 / NOx ratios are determined by subjecting the oxidation catalyst article to a feed gas containing 600 ppm of NO, 10% O2, 5% CO2, 5% H2O and 33 ppm of propane at a temperature of 350 °C and space velocity. Petition 870260065670, dated 03 / 07 / 2026, p. 85 / 92 5 / 5 of 50,000 per hour when the substrate is a continuous flow substrate of 2.54 cm x 7.62 cm (1” x 3”), and the oxidation catalyst article has a platinum group metal loading of 0.06 g / l (1.7 g / ft3).

21. EXHAUST GAS TREATMENT SYSTEM, characterized by comprising the oxidation catalyst article, as defined in any one of claims 13 to 20, wherein the oxidation catalyst article is downstream of and in fluid communication with an internal combustion engine.

22. SYSTEM, according to claim 21, characterized by further comprising one or more catalytic articles selected from a urea injector, a selective catalytic reduction (SCR) catalyst, an ammonia oxidation catalyst (AMOx), a low-temperature NOx adsorbent (LTNA) and a lean NOx trap (LNT).

23. METHOD FOR TREATING AN EXHAUST GAS STREAM, comprising hydrocarbons, carbon monoxide and / or NOx, characterized by comprising passing the exhaust gas stream through the catalytic article, as defined in any one of claims 13 to 20, or the exhaust gas treatment system, as defined in any one of claims 21 to 22. Petition 870260065670, dated 03 / 07 / 2026, pp. 86 / 92

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