SCRF coating

Abstract

The present disclosure relates to a coated filter for filtering particulate matter from exhaust gases. The filter has a porous catalytic composition coating, the catalytic composition including zeolite, copper, and manganese. The present disclosure also relates to a method of forming the coated filter described herein, and an exhaust system including the coated filter described herein.

Description

[Technical Field]

[0001] The present disclosure relates to a coated filter for filtering particulate matter from exhaust gases. The filter has a porous catalytic composition coating, the catalytic composition including zeolite, copper, and manganese. The present disclosure also relates to a method of forming the coated filter described herein, and an exhaust system including the coated filter described herein. [Background technology]

[0002] There are concerns regarding emissions of particulate matter (PM), commonly referred to as soot, from internal combustion engines, particularly diesel and gasoline engines for automotive applications. The main concerns relate to potential health effects, specifically those related to very small particles with sizes in the nanometer range.

[0003] Diesel particulate filters (DPFs) and gasoline particulate filters (GPFs) have been manufactured using a variety of materials, including sintered metal, ceramic, or metal fiber. However, the most common type in practical mass production is the wall-flow variety, made from porous ceramic materials fabricated in the form of a monolithic array of many small channels extending along the length of the body. The alternating channels are plugged at one end, forcing exhaust gases through the porous ceramic channel walls, which prevent the majority of particulates from passing through, allowing only filtered gases to enter the environment. Commercially produced ceramic wall-flow filters include those made from cordierite, various forms of silicon carbide, and aluminum titanate. The actual shape and dimensions of practical filters on vehicles, as well as characteristics such as the thickness and porosity of the channel walls, depend on the application involved. The average size of the pores in the filter channel walls through which gases pass is typically in the range of 5 to 50 μm, usually around 20 μm. In sharp contrast, most diesel particulate matter from modern passenger car high speed diesel engines is smaller in size, eg, 10-200 nm.

[0004] Some PM may be retained within the pore structure within the filter wall, which in some applications may gradually accumulate until the pores are spanned by a network of PM, which then allows a cake of particulates to readily form on the inner walls of the filter channels. The particulate cake is an excellent filter medium, and its presence results in very high filtration efficiency. In some applications, soot is continuously burned on the filter as it is deposited, which prevents the particulate cake from building up on the filter.

[0005] Some filters, such as light-duty diesel particulate filters, require periodic removal of trapped PM from the filter to prevent excessive backpressure buildup, which can be detrimental to engine performance and reduce fuel economy. In diesel applications, the retained PM is removed from the filter by burning it in air during a process during which the amount of available air and the amount of excess fuel used to achieve the high temperatures necessary to ignite the retained PM are very carefully controlled. Toward the end of this process, typically called regeneration, removal of the last remaining particulates in the filter can significantly reduce filtration efficiency and lead to the burst release of many small particles into the environment. Thus, filters can have low filtration efficiency when they are first used, after each subsequent regeneration event, and during the latter part of each regeneration process.

[0006] It is therefore desirable to constantly improve and / or maintain filtration efficiency, for example during the initial life of the filter when first used, and / or during and immediately after regeneration, and / or when soot accumulates on the filter.

[0007] Jiang et al. (Journal of Chemistry, 2020, article ID: 1462801) described powder catalyst preparations using different zeolites doped with Cu and either Ce or Mn. NOx conversion was evaluated and the 4% Cu / SSZ-13 catalyst was found to exhibit the best low-temperature catalytic activity, the widest temperature window of activity, and the highest overall SCR deNOx performance. Ce doping improved the catalyst's low-temperature deNOx performance and broadened the temperature window.

[0008] Wei et al. (Chemical Engineering Journal, 391, 2020, 123491) reported the seed-assisted synthesis of CuMn UZM-9 zeolite. The introduction of Mn promoted low-temperature activity and suppressed NO formation at high temperatures.

[0009] Zhang et al. (Applied Catalysis A, General 543, 2017, 247-256) describe a powdered Cu-SAPO-34 catalyst doped with Fe and MnCe. The results show that doping results in high SO2 resistance, high hydrothermal stability, and lower NO yield.

[0010] WO 2021 / 028692 (incorporated herein by reference in its entirety) describes a vehicle exhaust filter, the vehicle exhaust filter comprising a porous substrate having an inlet face and an outlet face, the porous substrate including inlet channels extending from the inlet face and outlet channels extending from the outlet face, the inlet channels and the outlet channels being separated by a plurality of filter walls having a porous structure, the vehicle exhaust filter having a pore size of 0.10 g / cm 3 and a vehicle exhaust filter is described in which the vehicle exhaust filter is filled with a refractory powder having a tap density before filling of less than 10 g / L, the refractory powder having a mass loading of less than 10 g / L, more than 40% of the refractory powder being disposed within the porous structure of the plurality of filter walls, and less than 60% of the refractory powder being coated on the exterior surfaces of the plurality of filter walls. WO 2021 / 028692 also describes suitable methods and apparatus for spraying a dry refractory powder, such as a dry particulate aerosol, onto channels of a porous substrate, preferably more than 50% of the refractory powder, and optionally up to 100% of the refractory powder, may be disposed within the porous structure of the plurality of filter walls.

[0011] WO 2020 / 047356 (the entire contents of which are incorporated herein by reference) relates to a catalyst composition for treating exhaust gases, which comprises a molecular sieve containing exchanged copper and exchanged manganese. The catalyst composition of WO 2020 / 047356 is used to form a non-porous coating on an article.

[0012] The present inventors have developed the present invention to mitigate and / or overcome problems found in the prior art. The present invention advantageously provides an improved method for producing more efficient coated monolith filters that exhibit improved filtration efficiency and less NO formation without increasing backpressure. Summary of the Invention

[0013] The present invention relates to a coated filter for filtering particulate matter from exhaust gases, the filter having a catalytic composition coating comprising: a) zeolite, b) copper, and c) manganese, Including, The catalyst composition is porous.

[0014] The present invention further relates to methods of forming coated filters (e.g., the coated filters described herein) and to calcined, coated filters (e.g., the calcined, coated filters described herein).

[0015] The present invention also relates to a coated filter / calcined coated filter for treating exhaust gases, and to a vehicle exhaust system including the coated filter / calcined coated filter. [Brief explanation of the drawings]

[0016] [Figure 1] Porosimetry data for non-porous and porous coatings are shown. [Figure 2] NOx conversion data at 600°C is shown. [Figure 3] Nox conversion data at 250°C is shown. [Figure 4] The data on the amount of N2O produced at 600°C is shown. [Figure 5] The data on the amount of N2O produced at 250°C is shown. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention relates to a coated filter for filtering particulate matter from exhaust gases, the filter having a catalytic composition coating comprising: a) zeolite, b) copper, and c) manganese, Including, The catalyst composition is porous.

[0018] In further embodiments, the present invention further relates to methods of forming coated filters (e.g., the coated filters described herein) and to calcined, coated filters (e.g., the calcined, coated filters described herein).

[0019] In further embodiments, the present invention also relates to coated filters / calcined and coated filters for treating exhaust gases (e.g., coated filters / calcined and coated filters described herein).

[0020] In a further embodiment, the present invention relates to a vehicle exhaust system comprising a coated filter / calcined, coated filter (e.g., a coated filter / calcined, coated filter described herein).

[0021] The present disclosure will now be further described. In the following sections, different aspects / embodiments of the present disclosure are defined in more detail. Each aspect / embodiment so defined may be combined with any other aspect / embodiment or aspects / embodiments, unless expressly indicated otherwise. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

[0022] The catalyst composition of the present invention is porous. The porous structure has good gas permeability and does not significantly increase exhaust gas back pressure. Porosity is generally understood to mean the ratio of the pore volume to the total volume of a substance or object. The porous composition of the present invention can have a defined porosity and pore size distribution and is created by a pore-forming agent. The porous structure is created by burning the pore-forming agent at high temperatures (e.g., 400 to 800°C, preferably 450 to 750°C, most preferably about 500°C).

[0023] Zeolite The catalyst composition of the present invention comprises at least one zeolite. Zeolites are structures formed from alumina and silica, and SAR determines the reactive sites within the zeolite structure. Zeolites useful in the present invention may include small pore zeolites (e.g., zeolites having a maximum ring size of 8 tetrahedral atoms), medium pore zeolites (e.g., zeolites having a maximum ring size of 10 tetrahedral atoms), large pore zeolites (e.g., zeolites having a maximum ring size of 12 tetrahedral atoms), or a combination of two or more thereof.

[0024] When the catalyst composition comprises a small pore zeolite, the small pore zeolite may have a framework structure represented by a Framework Type Code (FTC) selected from the group including (e.g., consisting of): ACO, AEI, AEN, AFN, AFT, AFX, ANA, APC, APD, ATT, CDO, CHA, DDR, DFT, EAB, EDI, EPI, ERI, GIS, GOO, IHW, ITE, ITW, LEV, LTA, KFI, MER, MON, NSI, OWE, PAU, PHI, RHO, RTH, SAT, SAV, SFW, SIV, THO, TSC, UEI, UFI, VNI, YUG, and ZON, or mixtures and / or combinations of two or more thereof, and / or intergrowth. In some embodiments, the small pore zeolite has a framework structure selected from the group including (e.g., consisting of) CHA, LEV, AEI, AFX, ERI, LTA, SFW, KFI, DDR, and ITE. In some embodiments, the small pore zeolite has a framework structure selected from the group including (e.g., consisting of) CHA and AEI. The small pore zeolite may have a CHA framework structure.

[0025] When the catalyst composition comprises a medium pore zeolite, the medium pore zeolite may have a framework structure represented by a framework type code (FTC) selected from the group including (e.g., consisting of): AEL, AFO, AHT, BOF, BOZ, CGF, CGS, CHI, DAC, EUO, FER, HEU, IMF, ITH, ITR, JRY, JSR, JST, LAU, LOV, MEL, MFI, MFS, MRE, MTT, MVY, MWW, NAB, NAT, NES, OBW, PAR, PCR, PON, PUN, RRO, RSN, SFF, SFG, STF, STI, STT, STW, SVR, SZR, TER, TON, TUN, UOS, VSV, WEI, and WEN, or mixtures of two or more thereof and / or intergrowth. In some embodiments, the medium pore zeolite has a framework structure selected from the group including (e.g., consisting of): FER, MEL, MFI, and STT. In some embodiments, the medium pore zeolite has a framework structure selected from the group including (e.g., consisting of) FER and MFI, particularly MFI. When the medium pore zeolite has a FER or MFI framework, the zeolite can be ferrierite, silicalite, or ZSM-5.

[0026] When the catalyst composition comprises a large pore zeolite, the large pore zeolite may have a framework structure represented by a Framework Type Code (FTC) selected from the group including (e.g., consisting of): AFI, AFR, AFS, AFY, ASV, ATO, ATS, BEA, BEC, BOG, BPH, BSV, CAN, CON, CZP, DFO, EMT, EON, EZT, FAU, GME, GON, IFR, ISV, ITG, IWR, IWS, IWV, IWW, JSR, LTF, LTL, MAZ, MEI, MOR, MOZ, MSE, MTW, NPO, OFF, OKO, OSI, RON, RWY, SAF, SAO, SBE, SBS, SBT, SEW, SFE, SFO, SFS, SFV, SOF, SOS, STO, SSF, SSY, USI, UWY, and VET, or mixtures of two or more thereof and / or intergrowths. In some embodiments, the large pore zeolite has a framework structure selected from the group including (e.g., consisting of) AFI, BEA, MAZ, MOR, and OFF. In some embodiments, the large pore zeolite has a framework structure selected from the group including (e.g., consisting of) BEA, MOR, and FAU. When the large pore zeolite has a framework structure of FTC, BEA, FAU, or MOR, the zeolite can be beta zeolite, faujasite, zeolite Y, zeolite X, or mordenite.

[0027] In one embodiment, the catalyst composition of the present invention comprises a zeolite selected from CHA, AEI, FER, MFI, STW, BEA, FAU, AI, MAZ, MOR, and OFF, preferably CHA or AEI, more preferably CHA.

[0028] In a preferred embodiment, the catalyst composition of the present invention comprises a CHA or AEI zeolite, more preferably a CHA zeolite.

[0029] The catalyst composition of the present invention preferably comprises a zeolite having an SAR of 10 to 30, more preferably about 11 to about 28, e.g., about 12 to about 25, about 13 to 22, about 14 to about 21, about 15 to about 20, about 16 to about 19, or about 15 to about 18. The silica-to-alumina ratio of the zeolite can be determined by conventional analysis. By this ratio, it is meant to represent as closely as possible the ratio in the rigid atomic framework of the zeolite crystal and to exclude silicon or aluminum in the channels, in the binder, or in cationic or other form. Because it can be difficult to directly measure the silica-to-alumina ratio of a zeolite after it has been combined with a binder material, particularly an alumina binder, these silica-to-alumina ratios are expressed in terms of the SAR of the zeolite itself, i.e., before the zeolite is combined with other catalyst components.

[0030] In a preferred embodiment, the catalyst composition of the present invention comprises a zeolite having an SAR of 10-30, preferably 17-22, for example 18-21, preferably about 19.

[0031] Preferably, the zeolite has a d of 0.1 μm to 100 μm, preferably 0.2 μm to 50 μm, 0.5 to 40 μm, 1 μm to 30 μm, 1.5 μm to 20 μm, 2 μm to 10 μm, 2.5 μm to 5 μm. 90 In a preferred embodiment, the inorganic particles have a d of 0.1 μm to 10 μm, 0.5 to 9 μm, 1 μm to 8 μm, 1.5 μm to 7 μm, 2 μm to 6 μm, 2.5 μm to 5.5 μm, 3 μm to 5 μm, 3.5 μm to 4.5 μm. 90 In a more preferred embodiment, the zeolite has a d of 3.8 to 4.4 μm, for example about 4 μm. 90 (by volume).

[0032] As used herein, "d 90 The term "(by volume)" refers to the amount of water measured by a Malvern Mastersizer® 3000 equipped with an Aero s dispersion unit available from Malvern Panalytical Ltd (Malvern, UK). 90Refers to measurements (by volume). Dispersion conditions: air pressure = 2 barg, feed rate = 65%, hopper gap = 1.2 mm. Refractive index and absorptivity parameters are set according to the instructions provided in the Malvern Mastersizer® 3000 user manual.

[0033] In a preferred embodiment, the zeolite is selected from CHA or AEI and has a SAR of 17 to 22. In a particularly preferred embodiment, the zeolite is CHA and has a SAR of 18 to 21, preferably about 19.

[0034] copper The catalyst composition of the present invention also includes copper. In some embodiments, copper is incorporated into the zeolite by, for example, ion exchange, spray drying, or heat one pot. Copper can be present in the catalyst composition in an amount of at least 1 wt%, at least 1.5 wt%, at least 2 wt%, at least 2.5 wt%, at least 3 wt%, or at least 3.5 wt%. Copper can be present in the catalyst composition in an amount of about 0.5 to about 5 wt%, about 1 to about 4.5 wt%, e.g., about 1.5 to about 4 wt%, about 2 to about 3.5 wt%, about 2.25 to about 3 wt%, or about 2.5 to about 2.8 wt%. In some embodiments, copper is present in the catalyst composition in an amount of about 2 wt%, about 2.25 wt%, about 2.5 wt%, about 2.75 wt%, about 3 wt%, or about 3.5 wt%. References to weight percent are based on the weight of the zeolite.

[0035] In one embodiment, the copper is present in an amount of about 0.5 to about 5 wt %, about 1 to about 4.5 wt %, for example about 2 to about 4 wt %, preferably about 2.75 wt %, based on the weight of the zeolite.

[0036] In a preferred embodiment, copper is present in the catalyst composition in an amount of 2 to 4 wt.%, for example about 2.75 wt.%.

[0037] When copper is incorporated, NO xIt has been found that the conversion is improved. It has also been found that the catalyst can be effective over a wide range of temperatures, with a very wide operating window. The incorporation of copper has been found to allow the catalyst to be effective at temperatures between 150 and 600°C.

[0038] manganese The catalyst composition of the present invention also contains manganese.

[0039] In some embodiments, the catalyst composition of the present invention is free of or essentially free of any additional transition metals (including lanthanides and actinides) other than copper and manganese. For example, in some aspects, the catalyst composition contains less than about 1 wt. %, less than about 0.7 wt. %, less than about 0.5 wt. %, less than about 0.3 wt. %, less than about 0.1 wt. %, less than about 0.07 wt. %, less than about 0.05 wt. %, or less than about 0.01 wt. % of the additional transition metal (i.e., in addition to copper and manganese) based on the weight of the molecular sieve.

[0040] The total manganese content of the catalyst composition can be in an amount of about 0.1 to about 3 wt %, about 0.25 wt % to about 2.5 wt %, about 0.5 wt % to about 2 wt %, about 0.65 to about 1.75 wt %, preferably 0.75 to about 1.5 wt %, and preferably about 1.0 wt %, based on the weight of the zeolite.

[0041] In a preferred embodiment, the total manganese content of the catalyst composition is between 0.65 and 1.75 wt.%, preferably between 0.75 and 1.5 wt.%, for example about 1 wt.%.

[0042] The incorporation of manganese has been found to improve the activity for conversion to nitrogen (compared to, for example, copper), particularly at temperatures above 400°C.

[0043] catalyst composition The catalyst composition comprises a zeolite, copper, and manganese. The catalyst composition may further comprise a binder, a rheology modifier, and / or a pore former.

[0044] Examples of binders are alumina (e.g., boehmite, alpha alumina, beta alumina, and gamma alumina), silica, (non-zeolitic) silica-alumina, natural clays, TiO2, ZrO2, and SnO2. In a preferred embodiment, the binder is selected from alumina binders such as boehmite, alpha alumina, beta alumina, and gamma alumina.

[0045] Examples of rheology modifiers are silanes, amines, acids, polysaccharides (starch, cellulose, galactomannan gum, xanthan gum, curdlan, etc.), dispersible cellulose (e.g., Natrosol), TEAOH (tetraethylammonium hydroxide), Dispex, and ammonia.

[0046] Examples of pore formers include cellulose pore formers, polyethylene, starch, graphite, polypropylene, polyaramid, polytetrafluoroethylene, polystyrene, cellulose fibers, and polymethacrylates such as Arbocel, Vivapur, Mipelon PM-200, Propyltex, Orgasol, and Remyrise.

[0047] In a preferred embodiment, the catalyst composition may comprise one or more alumina binders, rheology modifiers selected from Natrosol and TEAOH, and pore formers selected from Arbocel and Vivapur.

[0048] In some embodiments, the zeolite and pore former are present in a ratio of 10:1 to 1:3, preferably 8:1 to 1:2, 6:1 to 1:1.5, 5:1 to 1:1, 4:1 to 1.5:1, 3:1 to 2:1, for example 5:1 to 1:2 or 3:1 to 1:1.

[0049] In some embodiments, the zeolite and binder (e.g., alumina binder) are present in a ratio of 20:1 to 1:1, such as 15:1 to 2:1, preferably 12:1 to 3:1, such as 10:1 to 5:1, more preferably about 9:1.

[0050] The catalyst compositions described herein can have a viscosity of 5 to 10,000 cPs, e.g., 6 to 5,000 cPs, 7 to 3,000 cPs, 8 to 2,000 cPs, 10 to 1800 cPs, 50 to 1700, 100 to 1600, 200 to 1500, 300 to 1400, 400 to 1200, 500 to 1100, 600 to 1000 cPs, 700 to 950 cPs, or 750 to 900 cPs.

[0051] Viscosity can be measured at 20° C. on a Brookfield RV DVII+Extra Pro viscometer using an SC4-27 spindle at a spindle speed of 50 rpm.

[0052] The compositions described herein can be used to coat the porous structure of a filter. One or more layers of the composition can be used to coat the filter. The one or more layers of the composition are then preferably calcined.

[0053] Preferably, the total composition loading of the coated filter is less than 0.1 g / in 3 ~10g / in 3 , preferably 0.1 g / in 3 ~8g / in 3 , 0.5g / in 3 ~7g / in 3 , 0.8g / in 3 ~6g / in 3 , 1g / in 3 ~5g / in 3 , 1.25g / in 3 ~4g / in 3 , 1.5g / in 3 ~3g / in 3 , 2g / in 3 ~2.5g / in 3 In a more preferred embodiment, the total composition loading of the coated filter is 0.5 g / in 3 ~5g / in 3 or 1 g / in 3 ~2.5g / in 3 is.

[0054] In some embodiments, the catalyst composition comprises a mixture of NH3 and NO x The catalyst composition is effective in promoting the reaction with Cu to produce nitrogen and water. In certain embodiments, the catalyst composition produces about 30% to about 50% less NO compared to Cu-exchanged zeolite under standard SCR conditions. In some embodiments, the catalyst composition produces about 30% to about 50% less NO compared to Cu-exchanged zeolite under high-temperature SCR conditions. In some embodiments, the catalyst composition produces about 30% to about 50% less NO compared to Cu-exchanged zeolite under low-temperature SCR conditions.

[0055] In some embodiments, the catalyst composition produces approximately the same total NO compared to Cu-exchanged zeolites at high temperature SCR conditions. x In some embodiments, the catalyst composition converts about 5 to about 25% more NO under low temperature SCR conditions compared to Cu-exchanged zeolites. x Transform.

[0056] The filters described herein can be coated with at least two catalyst compositions: a first catalyst composition and a second catalyst composition.

[0057] The first catalyst composition comprises a zeolite (e.g., as described herein), copper (e.g., as described herein), manganese (e.g., as described herein), and may further comprise a binder (e.g., as described herein, preferably selected from one or more aluminas), and a rheology modifier (e.g., as described herein, preferably selected from Natrosol and TEAOH).

[0058] The second catalyst composition is a catalyst composition described herein and may further include a binder (e.g., a binder described herein, preferably selected from one or more aluminas), a rheology modifier (e.g., a rheology modifier described herein, preferably selected from Natrosol and TEAOH), and a pore former (e.g., a pore former described herein, preferably selected from Arbocel and Vivapur).

[0059] The first catalyst composition can be present on the substrate over 50-100% of the length of the substrate, e.g., 55%-99%, 60%-98%, 65%-97%, 70%-96%, 75%-95%, or 80%-90%. In a preferred embodiment, the first catalyst composition is present on the substrate over 60-98%, 70-90%, preferably 75-85%, e.g., about 80% of the length of the substrate.

[0060] The first catalyst composition can further comprise one or more binders (e.g., a binder described herein such as those selected from the group comprising (e.g., consisting of) alumina (e.g., boehmite, alpha alumina, beta alumina, and gamma alumina), silica, (non-zeolitic) silica-alumina, natural clay, TiO2, ZrO2, and SnO2), and / or one or more rheology modifiers (e.g., a rheology modifier described herein such as Natrosol, TEAOH (tetraethylammonium hydroxide), Dispex, or ammonia). In a preferred embodiment, the first catalyst composition comprises a catalyst composition described herein, one or more aluminas (e.g., boehmite, alpha alumina, beta alumina, and gamma alumina), and one or more rheology modifiers selected from Natrosol and TEAOH.

[0061] The first catalyst composition may be an in-wall coating. An in-wall coating is when most or all of the composition is present within the pores of the porous substrate. A portion of the in-wall coating may be present on-wall. "On-wall" means that the coating is present as a coating on the wall of the substrate. In some embodiments, 60-100%, preferably 70-99%, 75-98%, 80-98%, 85-97%, or 90-96% of the first catalyst composition is present on-wall. In alternative embodiments, at least 60%, at least 70%, at least 75%, at least 80%, at least 90%, or at least 95% of the first catalyst composition is present on-wall.

[0062] As will be appreciated by those skilled in the art, the percentage of the coating that is "on-wall" or "in-wall" can be determined by techniques known in the art, such as scanning electron microscopy (SEM) or optical microscopy.

[0063] The viscosity of the first catalyst composition can be from 2 to 20 cPs, for example, from 3 to 15 cPs, from 4 to 12, from 5 to 10, or from 6 to 8, for example, from 2 to 10 cPs. In another embodiment, the viscosity of the first catalyst composition is less than 20 cPs, for example, less than 15 cPs or less than 10 cPs.

[0064] The second catalyst composition can be present on the substrate over 50-100% of the length of the substrate, e.g., 55-99%, 60-98%, 65-97%, 70-96%, 75-95%, or 80-90%. In a preferred embodiment, the second catalyst composition is present on the substrate over 50-100%, preferably 75-98%, 85-95%, e.g., about 90% of the length of the substrate.

[0065] The second catalyst composition comprises a catalyst composition described herein. In some embodiments, the second catalyst composition can further comprise one or more binders (e.g., those described herein, such as those selected from the group including (e.g., consisting of) alumina (such as boehmite, alpha alumina, beta alumina, and gamma alumina), silica, (non-zeolitic) silica-alumina, natural clay, TiO2, ZrO2, and SnO2), one or more rheology modifiers (e.g., a rheology modifier described herein, such as Natrosol, TEAOH (tetraethylammonium hydroxide), Dispex, or ammonia), and / or one or more pore formers (e.g., a pore former described herein, such as a cellulose pore former, polyethylene, starch, graphite, polypropylene, polyaramid, polytetrafluoroethylene, polystyrene, cellulose fiber, and polymethacrylate, e.g., Arbocel, Vivapur, Mipelon PM-200, Propyltex, Orgasol, and Remyrise). In a preferred embodiment, the second catalyst composition comprises a catalyst composition described herein, one or more aluminas (e.g., boehmite, alpha alumina, beta alumina, and gamma alumina), one or more rheology modifiers selected from Natrosol and TEAOH, and one or more pore formers selected from Arbocel and Vivapur.

[0066] The second catalyst composition may be an on-wall coating. A portion of the on-wall coating may be present in the in-wall. In some embodiments, 60-100%, preferably 70-99%, 75-98%, 80-98%, 85-97%, or 90-96% of the second catalyst composition is present on-wall. In other embodiments, at least 60%, at least 70%, at least 75%, at least 80%, at least 90%, or at least 95% of the second catalyst composition is present on-wall.

[0067] The viscosity of the second catalyst composition can be 5 to 10,000 cPs, 6 to 5,000 cPs, 7 to 3,000 cPs, 8 to 2,000 cPs, 10 to 1800 cPs, 50 to 1700, 100 to 1600, 200 to 1500, 300 to 1400, 400 to 1200, 500 to 1100, 600 to 1000 cPs, 700 to 950 cPs, or 750 to 900 cPs.

[0068] In some embodiments, the weight ratio of the first catalyst composition to the second catalyst composition is from 1:1 to 5:1, such as from 2:1 to 4:1, preferably from 2.5:1 to 3:1, such as about 2.5:1.

[0069] In some embodiments, the proportion of the first catalyst composition present relative to the total amount of catalyst composition is 60-80%, such as 65-75%, for example, about 70%, and the proportion of the second catalyst composition present relative to the total amount of catalyst composition can be 20-40%, such as 25-35%, for example, about 30%.

[0070] filter The filter may be made of, for example, sintered metal, ceramic, or metal fibers, etc. For example, the filter may be made of cordierite, various forms of silicon carbide, or aluminum titanate.

[0071] In some embodiments, the filter is a monolith filter. It is particularly preferred that the monolith filter is a wall-flow filter. Wall-flow filters are well known and typically have adjacent channels alternately blocked at each end of the monolith filter such that, in use, exhaust gas passes along the inlet channels (i.e., channels that are open at the inlet end of the monolith filter to receive the exhaust gas) and passes through the channel walls into adjacent outlet channels (i.e., channels that are open at the outlet end of the monolith filter).

[0072] The channel walls have a distribution of micropores that provides the required porosity for the monolith filter, with the average pore size in the channel walls, e.g., filter walls, typically ranging from 5 to 50 μm. Each channel has a gas-contacting surface, i.e., a surface suitable for contact with, for example, exhaust gases, during use. The surface may be provided by the channel wall surface and / or the pores contained therein.

[0073] In another particularly preferred embodiment, the monolith filter is a catalytic filter (i.e., catalytic filter). Catalytic filters are well known and are used to remove NOx, NO2, and other pollutants. x They exhibit catalytic functions such as scavenging or selective catalytic reduction activity.

[0074] The shape and dimensions of the filter, such as channel wall thickness and its porosity, may vary depending on the intended use of the filter. The filter may be configured for use with an internal combustion engine to filter exhaust gases emitted by the internal combustion engine. The internal combustion engine may be a gasoline spark-ignition engine. However, the filter may also be used when configured for use with an internal combustion engine in the form of a diesel or gasoline engine.

[0075] A monolith filter can have multiple channels for passing exhaust gas, each channel having a gas-contacting surface. Monolith filters are well known in the art. A monolith filter is sometimes referred to as a substrate, preferably a honeycomb substrate, preferably a ceramic honeycomb substrate. Such a substrate includes multiple channels suitable for passing exhaust gas. The multiple channels are parallel and extend from an inlet end (or first end) to an outlet end (or second end). That is, the channels extend axially through the filter. Adjacent channels are alternately blocked at each end of the monolith filter so that, in use, exhaust gas passes along the inlet channel (i.e., a channel open at the inlet end of the monolith filter to receive exhaust gas) and passes through the channel wall into an adjacent outlet channel (i.e., a channel open at the outlet end of the monolith filter). A monolith filter can have multiple inlet channels and multiple outlet channels. Typically, the channels have a square cross-section, but any known monolith design can be used.

[0076] Preparation method A further aspect of the present invention is directed to a method of preparing a catalyst composition (eg, a catalyst composition described herein), comprising incorporating copper and manganese into a zeolite.

[0077] The present invention provides a method of forming a coated filter (e.g., a filter coated with the catalyst composition described herein), comprising: i) incorporating copper and manganese into a zeolite to form a catalyst composition; ii) forming a first washcoat comprising the catalyst composition of step i), one or more binders, and one or more rheology modifiers (e.g., one or more binders and one or more rheology modifiers described herein); iii) applying the first washcoat to a filter (e.g., a filter described herein); iv) optionally drying the filter; v) forming a second washcoat comprising the catalyst composition of step i), one or more binders, one or more rheology modifiers, and one or more pore formers (e.g., one or more binders, one or more rheology modifiers, and one or more pore formers described herein); vi) applying the second washcoat to the first washcoat-coated filter from step iii) or step iv); vii) drying and calcining the article to form a coated filter (e.g., a filter coated with a catalyst composition described herein); The present invention relates to a method comprising the steps of:

[0078] The catalyst composition can be prepared by methods known in the art, such as spray drying, ion exchange, and one-pot heating. Spray drying can be performed sequentially or in combination. For example, in a sequential spray drying method, copper is spray dried onto a zeolite material. This material is calcined, then spray dried again with manganese, and calcined again. In a combined spray drying method, a slurry of a soluble precursor of copper (e.g., copper acetate or copper carbonate), a soluble precursor of manganese (e.g., manganese acetate), and the zeolite is prepared, and the resulting slurry is spray dried in one step. In an alternative embodiment, one-pot heating can be performed, in which a soluble precursor of copper (e.g., copper acetate or copper carbonate) is added to a slurry of the zeolite, which is then heated (e.g., to about 60-140°C, preferably about 70°C) for a period of time (e.g., 1-6 hours, preferably about 2 hours). A soluble precursor of manganese (eg, manganese acetate) is added, and this is maintained at the same temperature for an additional period of time (eg, 1 to 6 hours, preferably about 2 hours).

[0079] In a preferred embodiment, the catalyst composition is prepared by combinatorial spray drying, which has been found to have the fewest problems with side reactions and required additional steps, and has been found to be the most cost and time efficient.

[0080] The catalyst composition described herein can be incorporated into the washcoat. In addition to the catalyst composition, the washcoat composition can also include: (i) one or more binders, such as those described herein, selected from the group including (e.g., consisting of) alumina (e.g., boehmite, alpha alumina, beta alumina, and gamma alumina), silica, (non-zeolitic) silica-alumina, natural clays, TiO2, ZrO2, and SnO2; and / or (ii) one or more rheology modifiers (e.g., those described herein, such as Natrosol, TEAOH (tetraethylammonium hydroxide), Dispex, or ammonia), and / or (iii) one or more pore formers (e.g., cellulose pore formers, polyethylene, starch, graphite, polypropylene, polyaramid, polytetrafluoroethylene, polystyrene, cellulose fibers, and polymethacrylates, e.g., Arbocel, Vivapur, Mipelon PM-200, Propyltex, Orgasol, and Remyrise, for example, as described herein). It may further include:

[0081] The washcoat may be applied to a substrate such as a metal or ceramic flow-through monolith substrate, or a filtration substrate including, for example, a wall-flow filter or a sintered metal or partial filter.

[0082] The washcoat can be applied to the substrate using any conventional method, such as an Automated Inversion Depositor (AID) process or a Precision Coating (PC) process. The AID process involves using a piston to force the washcoat into a filter, flipping the part over, and then allowing the washcoat to soak into the walls of the substrate. The PC process involves using a showerhead to apply a precise dosage rate, and the washcoat is drawn into the part by gravity and / or vacuum, allowing the washcoat to soak into the walls of the substrate. In a preferred embodiment, the washcoat is applied to the substrate using the PC process.

[0083] In some embodiments, two or more applications of the washcoat are applied to the substrate.

[0084] The first application of washcoat can be applied to the substrate along 50-100% of the length of the substrate, e.g., 55%-99%, 60%-98%, 65%-97%, 70%-96%, 75%-95%, or 80%-90%. In a preferred embodiment, the first application of washcoat is applied to the substrate along 70%-90%, preferably 75%-85%, e.g., about 80% of the length of the substrate.

[0085] The first application of washcoat comprises a catalyst composition described herein. In some embodiments, the first application of washcoat can further comprise one or more binders (e.g., such as those described herein selected from the group including (e.g., consisting of) alumina (e.g., boehmite, alpha alumina, beta alumina, and gamma alumina), silica, (non-zeolitic) silica-alumina, natural clay, TiO2, ZrO2, and SnO2), and / or one or more rheology modifiers (e.g., such as those described herein, such as Natrosol, TEAOH (tetraethylammonium hydroxide), Dispex, or ammonia). In a preferred embodiment, the first application of washcoat comprises a catalyst composition described herein, one or more aluminas (e.g., boehmite, alpha alumina, beta alumina, and gamma alumina), and one or more rheology modifiers selected from Natrosol and TEAOH.

[0086] The first application of washcoat can be an in-wall coating. An in-wall coating is when most or all of the washcoat is present within the pores of the porous substrate. Some of the in-wall coating can also be present on-wall. On-wall means that the washcoat is present as a coating on the wall of the substrate. In some embodiments, 60-100%, preferably 70-99%, 75-98%, 80-98%, 85-97%, or 90-96% of the first application of washcoat is present on-wall. In alternative embodiments, at least 60%, at least 70%, at least 75%, at least 80%, at least 90%, or at least 95% of the first application of washcoat is present on-wall.

[0087] As will be appreciated by those skilled in the art, the percentage of the coating that is "on-wall" or "in-wall" can be determined by techniques known in the art, such as scanning electron microscopy (SEM) or optical microscopy.

[0088] The viscosity of the first application of washcoat may be 2 to 20 cPs, for example, 3 to 15 cPs, 4 to 12, 5 to 10, 6 to 8, e.g., 2 to 10 cPs. In alternative embodiments, the viscosity of the first application of washcoat is less than 20 cPs, for example, less than 15 cPs or less than 10 cPs.

[0089] The second application amount of washcoat can be applied to the substrate along 50-100% of the length of the substrate, e.g., 55%-99%, 60%-98%, 65%-97%, 70%-96%, 75%-95%, or 80%-90%. In a preferred embodiment, the second application amount of washcoat is applied to the substrate along 75%-100%, preferably 80%-98%, more preferably 85%-95%, e.g., about 90% of the length of the substrate.

[0090] The second application of washcoat comprises a catalyst composition described herein. In some embodiments, the second application of washcoat can further comprise one or more binders (e.g., those described herein, such as those selected from the group including (e.g., consisting of) alumina (such as boehmite, alpha alumina, beta alumina, and gamma alumina), silica, (non-zeolitic) silica-alumina, natural clay, TiO2, ZrO2, and SnO2), one or more rheology modifiers (e.g., those described herein, such as Natrosol, TEAOH (tetraethylammonium hydroxide), Dispex, or ammonia), and / or one or more pore formers (e.g., those described herein, such as cellulose pore formers, polyethylene, starch, graphite, polypropylene, polyaramid, polytetrafluoroethylene, polystyrene, cellulose fibers, and polymethacrylates, e.g., Arbocel, Vivapur, Mipelon PM-200, Propyltex, Orgasol, and Remyrise). In a preferred embodiment, the second application of the washcoat comprises a catalyst composition described herein, one or more aluminas (e.g., boehmite, alpha alumina, beta alumina, and gamma alumina), one or more rheology modifiers selected from Natrosol and TEAOH, and one or more pore formers selected from Arbocel and Vivapur.

[0091] The second application of washcoat can be an on-wall coating. A portion of the on-wall coating can be present in-wall. In some embodiments, 60-100%, preferably 70-99%, 75-98%, 80-98%, 85-97%, or 90-96% of the second application of washcoat is present on-wall. In alternative embodiments, at least 60%, at least 70%, at least 75%, at least 80%, at least 90%, or at least 95% of the second application of washcoat is present on-wall.

[0092] The viscosity of the second application amount of washcoat can be 5 to 10,000 cPs, e.g., 6 to 5,000 cPs, 7 to 3,000 cPs, 8 to 2,000 cPs, 10 to 1800 cPs, 50 to 1700, 100 to 1600, 200 to 1500, 300 to 1400, 400 to 1200, 500 to 1100, 600 to 1000 cPs, 700 to 950 cPs, or 750 to 900 cPs.

[0093] The coated substrate is preferably dried and calcined. The drying and / or calcining step can be performed after each individual washcoat application. In an alternative embodiment, the drying and / or calcining step is performed after all washcoat application doses have been applied. In a preferred embodiment, the substrate is dried after each washcoat application and then calcined once all washcoat application doses have been applied. In another embodiment, the substrate is dried and calcined after each washcoat application dose.

[0094] In a preferred embodiment, a substrate is coated with a first washcoat (e.g., a first washcoat described herein), and the resulting coated substrate is then dried. The dried coated substrate is then coated with a second washcoat (e.g., a second washcoat described herein), and the resulting coated substrate is then dried and calcined.

[0095] Preferably, the drying step is carried out at about 100-120°C. Preferably, the drying step is carried out for 15 minutes to 2 hours, for example, 20 minutes to 1 hour. The drying step can be used to remove at least 80%, at least 85%, at least 90%, at least 95%, or at least 98% of the moisture present in the coating. In a preferred embodiment, the drying step removes at least 90% of the moisture present in the coating.

[0096] The dried coated substrate may then be calcined at a temperature of 400 to 800° C., preferably 450 to 750° C., for example, about 500° C. Preferably, the calcination step comprises heating to a temperature of at least 200° C., preferably at least 300° C., more preferably at least 400° C., and / or up to 1000° C., up to 900° C., up to 800° C., up to 700° C., up to 600° C., preferably up to 550° C., more preferably up to 530° C. Thus, calcining preferably comprises heating to a temperature of 200 to 1000° C., preferably 300 to 900° C., preferably 400 to 800° C., more preferably 400 to 700° C., even more preferably 450 to 550° C., for example, about 500° C.

[0097] Such temperatures have been found to be most suitable for forming calcined, coated filters with improved filtration efficiency and increased water resistance. These temperatures are particularly advantageous when the coated filter is a coated catalytic filter, such as a coated catalytic wall-flow filter, because they allow the silicone resin to be calcined to crosslinked silicon dioxide without adversely affecting catalytic efficiency (i.e., without degrading the coated catalytic filter). Ideally, the calcination temperature is kept as low as possible to reduce the possibility of affecting the catalytic activity of any catalyst present in the coated filter.

[0098] The average pore size of the calcined catalyst composition is preferably in the range of 0.1 μm to 10 μm, more preferably 0.2 μm to 8 μm, even more preferably 0.5 μm to 7 μm, 0.75 μm to 6 μm, 0.8 μm to 5 μm, 1 μm to 4 μm, 1.2 μm to 3 μm, 1.5 μm to 2 μm, preferably 1.6 μm to 1.8 μm. The average pore size of the calcined catalyst composition can be preferably in the range of 0.1 μm to 10 μm, 0.5 μm to 7 μm, 1 μm to 4 μm, 1.5 μm to 2 μm, more preferably 1.6 μm to 1.8 μm.

[0099] The average pore size of the calcined catalyst composition can be measured by techniques in the art, for example, by mercury intrusion porosimetry (MIP) on a Micromeritics Autopore instrument.

[0100] The pore size distribution shows three distinct pore sizes: about 0.1 μm to 1 μm, about 1.5 μm to 1.8 μm, and about 10 μm to 50 μm. Without being bound by theory, it is believed that the pore sizes of 0.1 μm to 1 μm correspond to the pore structure of a typical washcoat, the pore sizes of 1.5 μm to 1.8 μm correspond to the pore structure of a washcoat pore former material, and the pore sizes of 10 μm to 50 μm correspond to the pore structure of the substrate.

[0101] The inventors have surprisingly found that by forming a porous coating and using an on-wall washcoat, it is possible to form a washcoat with a greater coating depth without unacceptably increasing backpressure. The greater coating depth also allows for more effective capture of soot (i.e., better filtration) while also improving access to the active SCR material. The soot loading backpressure, SLBP (i.e., the backpressure when the filter is loaded with soot), has also been found to be lower. This is believed to be because the soot is not blocking the pores in the wall, which would otherwise result in high backpressure.

[0102] coated filters In a further aspect of the invention, there is provided herein a coated filter for treating exhaust gases, the coated filter comprising a catalyst composition described herein or obtainable by a method described herein.

[0103] The catalyst composition (e.g., a catalyst composition described herein) may be in the form of a washcoat, preferably a washcoat suitable for coating a filter, such as a metal or ceramic flow-through monolith filter, e.g., one comprising a wall-flow filter or a sintered metal or partial filter. Accordingly, another aspect of the present invention is a washcoat comprising the catalyst composition described herein. A further aspect of the present invention is a catalytic filter comprising the catalyst composition described herein, which may be applied as a washcoat.

[0104] A preferred filter for use is a monolith having a so-called honeycomb shape, which includes multiple adjacent parallel channels, each typically having a square cross section. The honeycomb shape provides a large catalyst surface with minimal overall size and pressure drop. The catalyst composition can be deposited on a filter monolith substrate, such as a flow-through monolith filter (e.g., a honeycomb monolith catalyst-supported structure having many small, parallel channels extending axially throughout the entire filter) or a wall-flow filter. In another embodiment, the catalyst composition is formed into an extruded catalyst. Preferably, the catalyst composition is coated on the filter in an amount sufficient to reduce NOx contained in the exhaust gas stream flowing through the filter. In certain embodiments, at least a portion of the filter may also contain a platinum group metal, such as platinum (Pt), to oxidize ammonia in the exhaust gas stream or to perform other functions, such as converting CO to CO2.

[0105] The catalytic filters described herein preferably include a honeycomb monolith body that includes a catalyst composition (eg, a catalyst composition described herein), preferably as a washcoat layer thereon.

[0106] Exhaust gas system and method According to a further aspect, there is provided an exhaust gas system comprising a coated filter as described herein or a filter made by the methods described herein, and optionally a combustion engine. The internal combustion engine may be a diesel engine, a lean-burn gasoline engine, or an engine powered by liquefied petroleum gas or natural gas. Preferably, the internal combustion engine is a diesel engine. The coated filter may be positioned downstream of the engine to treat exhaust gases emitted by the engine.

[0107] According to yet a further aspect of the present invention, there is provided a method for treating an exhaust gas, the method comprising contacting the exhaust gas with a coated filter as described herein.

[0108] Although preferred embodiments of the present invention have been described in detail herein, those skilled in the art will recognize that variations can be made without departing from the scope of the invention or the appended claims.

[0109] The invention will now be further described with reference to the following non-limiting examples and figures.

[0110] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Use of the term "comprising" is intended to be interpreted as including such features but not excluding other features, and is intended to include options of features necessarily limited to those recited. In other words, unless the context clearly dictates otherwise, this term also includes the limitations "consisting essentially of" (intended to mean that certain additional components may be present provided they do not materially affect the essential properties of the recited feature) and "consisting of" (intended to mean that when components are expressed as percentages by their proportions, these add up to 100%, while accounting for any unavoidable impurities, but that other features may not be included).

[0111] As used herein, the term "g / L" (grams per liter) refers to the mass of the powder divided by the volume of the filter.

[0112] The foregoing detailed description has been provided for purposes of illustration and example, and is not intended to limit the scope of the appended claims. Many variations of the presently preferred embodiments illustrated herein will be apparent to those skilled in the art and remain within the scope of the appended claims and their equivalents. [Example]

[0113] Example 1 - Preparation of Coated Filters Wash Coat 1: A washcoat containing Cu(2.75)Mn(1.0) zeolite (the zeolite is a CHA zeolite with an SAR of 19) and stabilized alumina suspended in water was prepared. Prior to adding the alumina, 4 wt. % TEAH (tetraethylammonium hydroxide) in the zeolite was added.

[0114] Wash Coat 2: A washcoat containing Natrasol (a cellulose thickener), Cu(2.75)Mn(1.0) zeolite (the zeolite is a CHA zeolite with an SAR of 19), Arbocel UFC100 (a cellulose pore former), and boehmite alumina suspended in water was prepared. The viscosity target was approximately 750-900 cPs.

[0115] Wash Coat 3: A washcoat containing Natrasol (a cellulose thickener), Cu(2.75)Mn(1.0) zeolite (a CHA zeolite with an SAR of 19), and stabilized alumina suspended in water was prepared. Prior to adding the alumina, 4 wt.% TEAH (tetraethylammonium hydroxide) was added to the zeolite. The viscosity target was 350-600 cPs, and the coating depth was 25-35%.

[0116] Preparation of porous coated filters: Washcoat 1 was applied to the outlet end of the filter, coating approximately 80% of the filter volume. Washcoat 2 was applied to the inlet end of the filter, coating approximately 90% of the filter volume.

[0117] Preparation of non-porous coated filters: Washcoat 1 was applied to the outlet end of the filter, coating approximately 80% of the filter volume. Washcoat 3 was applied to the inlet end of the filter, coating approximately 25% of the filter volume.

[0118] Example 2 - Porosimetry Porosimetry data was collected for the following compositions: 1. Non-porous coating: Cu(3.3) zeolite (the zeolite is a CHA zeolite with SAR 19) 2. Porous coating: Cu(3.3) zeolite (the zeolite is a CHA zeolite with SAR 19)

[0119] Two batches of non-porous coating were applied, one to the outlet end of the filter, covering approximately 80% of the filter volume, and the second to the inlet end, covering approximately 25% of the filter volume. Samples for porosimetry data were taken from the front, middle (overlap area), and rear of the part.

[0120] Two batches of porous coating were applied, one at the outlet end of the filter, covering approximately 80% of the filter volume, and the second at the inlet end, covering approximately 90% of the filter volume. Samples for porosimetry data were taken from the middle (overlap area) and rear of the part.

[0121] The parts were imaged using a scanning electron microscope (SEM) with backscattered electron detection. Hg porosimetry was used to characterize the porosity and pore size distribution, with samples taken from the front, middle, and back of the parts.

[0122] The pore size distribution in Figure 1 shows three different pore sizes: about 0.1 μm to 1 μm, about 1.5 μm to 1.8 μm, and about 10 μm to 50 μm. Without being bound by theory, it is believed that the pore sizes from 0.1 μm to 1 μm correspond to the typical washcoat pore structure (and are present in Compositions 1 and 2), the pore sizes from 1.5 μm to 1.8 μm (present only in Composition 2) correspond to the pore structure of the washcoat pore former material, and the pore sizes from 10 μm to 50 μm correspond to the substrate pore structure (and are present in Compositions 1 and 2). The pore sizes from 1.5 μm to 1.8 μm are not present in Non-Porous Coating 1, indicating that the porous coating has additional porous structure.

[0123] Example 3 - NOx Conversion NOx conversion was calculated at low temperature (250°C) and high temperature (600°C). Four different compositions were used. 1. Cu(2.75)Mn(1.0) zeolite (the zeolite is a CHA zeolite with an SAR of 19) 2. Cu(2.25)Mn(0.75) zeolite (the zeolite is a CHA zeolite with an SAR of 19) 3. Cu(3.3) zeolite (the zeolite is a CHA zeolite with an SAR of 19). 4. Cu(2.25) zeolite (the zeolite is a CHA zeolite with SAR 19).

[0124] The results are shown in Figures 2 and 3. In this case, a wall-flow monolith containing compositions 1-4 from the above examples is installed in the exhaust system of a diesel engine equipped with an upstream DOC and urea injection system before the wall-flow monolith. To probe the SCR performance of the catalyst, the engine is operated under the following conditions: Figure 3 - 250C, 400 kg / h, ANR (Ammonia NOx Ratio) 2.0; Figure 2 - 600C, 520 kg / h, ANR 0.6, 1.5, and 2.0. NOx before and after the wall-flow monolith is measured using FTIR.

[0125] As illustrated in Figure 2, the NOx conversion at 600°C is essentially the same for compositions 4 and 2, indicating that the presence of Mn does not adversely affect NOx conversion at high temperatures. At low temperatures, compositions according to the present invention were found to provide improved NOx conversion (see Figure 3).

[0126] Example 4 - NO production The NO production was calculated at low (250°C) and high (600°C) temperatures using four different compositions. 1. Cu(2.75)Mn(1.0) zeolite (the zeolite is a CHA zeolite with an SAR of 19) 2. Cu(2.25)Mn(0.75) zeolite (the zeolite is a CHA zeolite with an SAR of 19) 3. Cu(3.3) zeolite (the zeolite is a CHA zeolite with an SAR of 19). 4. Cu(2.25) zeolite (the zeolite is a CHA zeolite with SAR 19).

[0127] The results are shown in Figures 4 and 5. In this case, wall-flow monoliths containing compositions 1-4 from the above examples are installed in the exhaust system of a diesel engine equipped with an upstream DOC and urea injection system before the wall-flow monolith. To probe the SCR performance of the catalyst, the engine is operated under the following conditions: Figure 5 - 250C, 400 kg / h, ANR (Ammonia NOx Ratio) 2.0; Figure 4 - 600C, 520 kg / h, ANR 0.6, 1.5, and 2.0. NO before and after the wall-flow monolith is measured using FTIR.

[0128] As illustrated in Figure 4, the NOx conversion at 600°C is lower for compositions 1 and 2, indicating that the combination of Cu / Mn and zeolite according to the present invention exhibits improved NO production. This effect was also demonstrated at low temperatures (see Figure 5).

Claims

1. 1. A filter having a catalytic composition coating, the catalytic composition comprising: a) zeolite, b) copper, and c) manganese, Including, A filter wherein the catalyst composition is porous.

2. 2. The filter of claim 1, wherein the zeolite is selected from CHA, AEI, FER, MFI, STW, BEA, FAU, AI, MAZ, MOR, and OFF, preferably CHA or AEI, more preferably CHA.

3. A filter according to claim 1 or claim 2, wherein the zeolite has an SAR of 10 to 30, preferably 17 to 22, for example 18 to 21, preferably about 19.

4. 4. A filter according to any one of claims 1 to 3, wherein the copper is present in an amount of about 0.5 to about 5 wt. %, about 1 to about 4.5 wt. %, for example about 2 to about 4 wt. %, preferably about 2.75 wt. %, based on the weight of the zeolite.

5. 5. The filter of any of claims 1 to 4, wherein manganese is in an amount of about 0.1 to about 3 wt. %, about 0.25 wt. % to about 2.5 wt. %, about 0.5 wt. % to about 2 wt. %, about 0.65 to about 1.75 wt. %, preferably 0.75 to about 1.5 wt. %, preferably about 1.0 wt. %, based on the weight of the zeolite.

6. The filter of any one of claims 1 to 5, wherein the catalyst composition is calcined.

7. 7. The filter of claim 6, wherein the average pore size of the calcined catalyst composition is in the range of 0.1 μm to 10 μm, preferably 0.5 μm to 7 μm, 1 μm to 4 μm, 1.5 μm to 2 μm, preferably 1.6 μm to 1.8 μm.

8. The catalyst composition comprises: I. One or more binders, preferably alumina, silica, silica-alumina, natural clay, TiO ２ , ZrO ２ , or SnO ２ one or more binders selected from II. one or more rheology modifiers, preferably rheology modifiers such as Natrosol, TEAOH Dispex, or ammonia, and / or III. one or more pore formers, preferably selected from cellulose pore formers, polyethylene, starch, graphite, polypropylene, polyaramid, polytetrafluoroethylene, polystyrene, cellulose fibers, and polymethacrylates, e.g., Arbocel, Vivapur, Mipelon PM-200, Propyltex, Orgasol, and Remyrise; The filter of any one of claims 1 to 7, further comprising:

9. the filter is coated with at least two catalyst compositions, a first catalyst composition and a second catalyst composition; the first catalyst composition comprises a zeolite (e.g., as described in claims 2 and / or 3), copper (e.g., as described in claim 4), manganese (e.g., as described in claim 5), a binder, and a rheology modifier; The filter of any one of claims 1 to 8, wherein the second catalyst composition is as defined in any one of claims 1 to 5 and further comprises a binder, a rheology modifier, and a pore former.

10. 10. The filter of claim 9, wherein the first catalyst composition is coated along 50-100%, such as 60-98%, 70-90%, preferably about 80% of the length of the substrate.

11. 11. The filter of claim 9 or 10, wherein the first catalyst composition is an in-wall coating.

12. The filter of any one of claims 9 to 11, wherein the first catalyst composition has a viscosity of 2 to 20 cPs.

13. 13. A filter according to any one of claims 9 to 12, wherein the second catalyst composition is coated along 50 to 100%, for example 75 to 98%, for example 85 to 95%, preferably about 90% of the length of the substrate.

14. The filter of any one of claims 9 to 13, wherein the second catalyst composition is an on-wall coating.

15. A filter according to any one of claims 9 to 14, wherein the second catalyst composition has a viscosity of from 10 to 1800 cPs, preferably from 750 to 900 cPs.

16. 16. A filter according to any one of claims 9 to 15, wherein the weight ratio of the first catalyst composition to the second catalyst composition is from 1:1 to 5:1, preferably from 2:1 to 4:1, for example about 3:

1.

17. 19. A method of forming a coated filter (e.g., a filter coated with the catalyst composition of any one of claims 1 to 16), comprising the steps of: i) incorporating copper and manganese into a zeolite to form a catalyst composition; ii) forming a first washcoat comprising the catalyst composition of step i), one or more binders, and one or more rheology modifiers; iii) applying the first washcoat to the filter; iv) optionally drying the filter; v) forming a second washcoat comprising the catalyst composition of step i), one or more binders, one or more rheology modifiers, and one or more pore formers; vi) applying the second washcoat to the filter coated with the first washcoat from step iii) or step iv); vii) drying and calcining the article to form a coated filter; A method comprising:

18. 18. A filter according to claim 8 or claim 9 or a method according to claim 17, wherein the binder is one or more aluminas, the rheology modifier is selected from Natrosol and TEAOH, and the pore former is selected from Arbocel and Vivapur.

19. A filter according to any one of claims 1 to 16 or a filter made by the method according to claim 17 or 18 for treating exhaust gases.

20. A vehicle exhaust system comprising a filter according to any one of claims 1 to 16 or a filter made by the method according to claim 17 or 18.

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