Catalysts for selective catalytic reduction of NOx

Abstract

The present invention relates to a catalyst for selective catalytic reduction of NOx comprising: a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough; and a coating comprising a zeolitic material, copper, a first non-zeolitic oxide material comprising iron and aluminum, wherein at least 25% by weight of the first non-zeolitic oxide material consists of iron, calculated as Fe2O3.

Description

[Technical field]

[0001] The present invention relates to a catalyst for the selective catalytic reduction of NOx, a process for preparing a catalyst for the selective catalytic reduction of NOx, a catalyst obtained by said process, as well as the use of the catalyst of the invention. [Background technology]

[0002] Copper-based selective catalytic reduction catalysts (SCR) and selective catalyst reduction catalyst on filter (SCRoF) are known in the art and provide good NOx conversion. In this regard, US Patent No. 9,242,238 (B2) discloses a mixed catalyst comprising copper promoted 8-ring small pore molecular sieve and iron promoted 8-ring small pore molecular sieve. Furthermore, US Patent No. 9,352,307 (B2) discloses an SCR catalyst comprising a mixture of Cu-CHA and Fe-MFI for improving NOx conversion, and US Patent No. 9,999,877 (B2) discloses a mixed zeolite catalyst Cu-CHA / Fe-BEA for the treatment of NOx in gas streams.

[0003] However, especially in light of the increasingly stringent Euro 7 regulations, a good NOx conversion is not enough. 2 The limitation of O emissions has also become very important, resulting in excellent NOx conversion and nitrous oxide (N 2 There is a need to provide new catalysts for selective catalytic reduction of NOx that reduce NOx (O) formation. Summary of the Invention

[0004] Therefore, an object of the present invention is to provide a process for producing a nitrous oxide (N 2 The objective of the present invention is to provide a new catalyst for selective catalytic reduction of NOx that reduces NOx formation over a wide temperature range. Surprisingly, the catalyst of the present invention exhibits excellent NOx conversion and reduces N 2It has been found that it is possible to reduce O. Furthermore, the catalyst has improved thermal stability compared to the prior art.

[0005] Thus, the present invention provides a catalyst for selective catalytic reduction of NOx, comprising: a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough; A coating comprising a zeolitic material and a first non-zeolitic oxide material comprising copper, iron and aluminum, wherein at least 25% by weight of the first non-zeolitic oxide material is Fe. 2 O 3 and a coating consisting of iron calculated as

[0006] Preferably, the zeolite material included in the coating is ABW, ACO, AEI, AEL, AEN, AET, AFG, AFI, AFN, AFO, AFR, AFS, AFT, AFV, AFX, AFY, AHT, ANA, APC, APD, AST, ASV, ATN, ATO, ATS, ATT, ATV, AVL, AWO, AWW, BCT, BEA, BEC, BIK, BOF, BOG, BOZ, BPH, BRE, BSV, CAN, CAS, CDO, CFI, CGF, CGS, CHA, -CHI, -CLO, CON, CSV, CZP, DAC, DDR, DFO, DFT, DOH, DON, EAB, EDI, EEI, EMT, EON, EPI, ERI, ESV, ETR, EUO, * -EWT, EZT, FAR, FAU, FER, FRA, GIS, GIU, GME, GON, GOO, HEU, IFO, IFR, -IFU, IFW, IFY, IHW, IMF, IRN, IRR, -IRY, ISV, ITE, ITG, ITH, *-ITN, ITR, ITT, -ITV, ITW, IWR, IWS, IWV, IWW, JBW, JNT, JOZ, JRY, JSN, JSR, JST, JSW, KFI, LAU, LEV , LIO, -LIT, LOS, LOV, LTA, LTF, LTJ, LTL, LTN, MAR, MAZ, MEI, MEL, MEP, MER, MFI, MFS, MON, MOR, MOZ, * MRE, MSE, MSO, MTF, MTN, MTT, MTW, MVY, MWF, MWW, NAB, NAT, NES, NON, NPO, NPT, NSI, OBW, OFF, OKO, OSI, OSO, OWE, -PAR, PAU, PCR, PHI, PON, PO S, PSI, PUN, RHO, -RON, RRO, RSN, RTE, RTH, RUT, RWR, RWY, SAF, SAO, SAS, SAT, SAV, SBE, SBN, SBS, SBT, SEW, SFE, SFF, SFG, SFH, SFN, SFO, SFS, * SFV, SFW, SGT, SIV, SOD, SOF, SOS, SSF, * -SSO, SSY, STF, STI, * More preferably, the zeolitic material contained in the coating has a framework type selected from the group consisting of STO, STT, STW, -SVR, SVV, SZR, TER, THO, TOL, TON, TSC, TUN, UEI, UFI, UOS, UOV, UOZ, USI, UTL, UWY, VET, VFI, VNI, VSV, WEI, -WEN, YUG, ZON, mixtures of two or more thereof, and mixed types of two or more thereof, more preferably selected from the group consisting of CHA, AEI, RTH, LEV, DDR, KFI, ERI, AFX, mixtures of two or more thereof, and mixed types of two or more thereof, more preferably selected from the group consisting of CHA, AEI, RTH, AFX, mixtures of two or more thereof, and mixed types of two or more thereof, more preferably selected from the group consisting of CHA and AEI. More preferably, the zeolitic material contained in the coating has framework type CHA.

[0007] The framework structure of the zeolite material is preferably composed of Si, Al and O in an amount of 95 to 100% by weight, more preferably 98 to 100% by weight, and even more preferably 99 to 100% by weight.

[0008] Preferably, in the framework structure of the zeolitic material contained in the coating, the molar SiO 2 :Al 2 O 3 The molar ratio of Si to Al calculated as is in the range of 2:1 to 30:1, more preferably in the range of 5:1 to 28:1, more preferably in the range of 8:1 to 26:1. More preferably, the molar ratio of Si to Al calculated as is in the range of 2:1 to 30:1, more preferably in the range of 5:1 to 28:1, more preferably in the range of 8:1 to 26:1. 2 :Al 2 O 3 The molar ratio of Si to Al, calculated as, is in the range of 10:1 to 19:1, more preferably in the range of 12:1 to 18:1. Alternatively, more preferably, the molar SiO 2 :Al 2 O 3 The molar ratio of Si to Al calculated as follows is in the range of 20:1 to 25:1.

[0009] Preferably, the zeolitic material included in the coating, more preferably the zeolitic material having framework CHA, has an average crystallite size as measured by scanning electron microscopy of at least 0.1 micrometers, more preferably in the range of 0.1 to 3.0 micrometers, more preferably in the range of 0.3 to 1.5 micrometers, more preferably in the range of 0.4 to 1.0 micrometers.

[0010] Preferably, the amount of copper contained in the coating, calculated as CuO, is in the range of 2 to 10 wt.%, more preferably in the range of 2.5 to 8 wt.%, more preferably in the range of 3 to 7 wt.%, more preferably in the range of 3.5 to 6 wt.%, based on the weight of the zeolitic material.

[0011] Preferably, the zeolitic material contained in the coating comprises copper.

[0012] Preferably, the zeolite material contains iron, and the zeolite material contains Fe 2 O 3The amount of iron, calculated as, is more preferably in the range of 0.1 to 1.5 wt.%, more preferably in the range of 0.15 to 1.25 wt.%, more preferably in the range of 0.25 to 1 wt.%, more preferably in the range of 0.3 to 0.8 wt.%, based on the weight of the zeolitic material.

[0013] Preferably, the zeolite material comprises copper and iron. Preferably, the present invention relates to a catalyst for selective catalytic reduction of NOx, comprising: a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough; A coating comprising a zeolitic material and a first non-zeolitic oxide material comprising copper, iron and aluminum, wherein at least 25% by weight of the first non-zeolitic oxide material is Fe. 2 O 3 and a coating consisting of iron calculated as The present invention relates to a catalyst in which copper is contained in a zeolitic material, and the zeolitic material contains iron.

[0014] Alternatively, the zeolitic material is preferably substantially free of iron, more preferably free of iron. In other words, preferably 0-0.001 wt. %, more preferably 0-0.0001 wt. % of the zeolitic material is Fe. 2 O 3 The iron content is calculated as:

[0015] Preferably, the coating comprises a loading of the zeolite material in the range of 0.25 to 5 g / in3, more preferably in the range of 0.75 to 3 g / in3, more preferably in the range of 1 to 2.5 g / in3, more preferably in the range of 1.25 to 2.2 g / in3.

[0016] Preferably, the zeolitic material contained in the coating, more preferably having framework type CHA, has a molecular weight of 50 to 900 mm, determined as described in Reference Example 1. 2 / g, more preferably 150 to 700m 2 / g, more preferably 250 to 650 m 2 / g.

[0017] Preferably, 50 to 92% by weight of the coating consists of the zeolite material, more preferably 65 to 90% by weight, more preferably 70 to 85% by weight.

[0018] More preferably, when the substrate of the catalyst of the present invention is a flow-through substrate, 80-85% by weight of the coating is made of the zeolite material. Alternatively, when the substrate of the catalyst of the present invention is a wall-flow filter substrate, more preferably 72-78% by weight of the coating is made of the zeolite material.

[0019] Preferably, 25-65 wt. % of the first non-zeolitic oxide material is Fe, more preferably 30-60 wt. %, more preferably 40-55 wt. %, more preferably 45-55 wt. %. 2 O 3 The iron content is calculated as:

[0020] Preferably, 35 to 75% by weight of the first non-zeolitic oxide material is Al, more preferably 40 to 70% by weight, more preferably 45 to 60% by weight, more preferably 45 to 55% by weight. 2 O 3 The calculated aluminum content is:

[0021] Preferably, in the first non-zeolitic oxide material, the weight ratio Al 2 O 3 :Fe 2 O 3 The weight ratio of aluminum to iron, calculated as is in the range of 0.5:1 to 3:1, preferably in the range of 2.33:1 to 1.5:1, more preferably in the range of 0.8:1 to 1.2:1, more preferably in the range of 0.9:1 to 1.1:1.

[0022] Preferably, the first non-zeolitic oxide material is one or more of a mixture of oxides comprising Al and Fe, a mixed oxide comprising Al and Fe, and an oxide of Al impregnated with Fe, more preferably one or more of a mixed oxide comprising Al and Fe, and an oxide of Al impregnated with Fe.

[0023] Preferably, the first non-zeolitic oxide material is 50 to 300 m 2 / g, more preferably 80 to 160 m 2 / g.

[0024] Preferably, the coating comprises the first non-zeolitic oxide material in an amount in the range of 5 to 20% by weight, more preferably in the range of 7 to 15% by weight, more preferably in the range of 8 to 12% by weight, based on the weight of the zeolitic material.

[0025] Preferably, the present invention relates to a catalyst for selective catalytic reduction of NOx, comprising: a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough; A coating comprising a zeolitic material and a first non-zeolitic oxide material comprising copper, iron and aluminum, wherein at least 25% by weight of the first non-zeolitic oxide material is Fe. 2 O 3 and a coating consisting of iron calculated as The catalyst wherein the coating comprises a first non-zeolitic oxide material in an amount in the range of 5 to 20% by weight, more preferably in the range of 7 to 15% by weight, more preferably in the range of 8 to 12% by weight, based on the weight of the zeolitic material.

[0026] Preferably, the present invention relates to a catalyst for selective catalytic reduction of NOx, comprising: a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough; A coating comprising a zeolitic material and a first non-zeolitic oxide material comprising copper, iron and aluminum, wherein at least 25% by weight of the first non-zeolitic oxide material is Fe. 2 O 3 and a coating consisting of iron calculated as the coating comprises a first non-zeolitic oxide material in an amount in the range of 5 to 20 wt.%, more preferably in the range of 7 to 15 wt.%, more preferably in the range of 8 to 12 wt.%, based on the weight of the zeolitic material; The present invention relates to a catalyst in which the zeolitic material has a framework type selected from the group consisting of CHA, AEI, RTH, LEV, DDR, KFI, ERI, AFX, mixtures of two or more thereof, and mixed types of two or more thereof, more preferably selected from the group consisting of CHA, AEI, RTH, AFX, mixtures of two or more thereof, and mixed types of two or more thereof, more preferably selected from the group consisting of CHA and AEI, and the zeolitic material contained in the coating has framework type CHA.

[0027] In the context of the present invention, preferably in the catalyst the weight ratio of the zeolitic material to the first non-zeolitic oxide material is in the range of 5:1 to 20:1, more preferably in the range of 6.7:1 to 14.3:1, more preferably in the range of 8.3:1 to 12.5:1.

[0028] Preferably, the present invention relates to a catalyst for selective catalytic reduction of NOx, comprising: a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough; A coating comprising a zeolitic material and a first non-zeolitic oxide material comprising copper, iron and aluminum, wherein at least 25% by weight of the first non-zeolitic oxide material is Fe. 2 O 3 and a coating consisting of iron calculated as The catalyst has a weight ratio of the zeolitic material to the first non-zeolitic oxide material in the range of 5:1 to 20:1, more preferably in the range of 6.7:1 to 14.3:1, more preferably in the range of 8.3:1 to 12.5:1.

[0029] Preferably, the present invention relates to a catalyst for selective catalytic reduction of NOx, comprising: a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough; A coating comprising a zeolitic material and a first non-zeolitic oxide material comprising copper, iron and aluminum, wherein at least 25% by weight of the first non-zeolitic oxide material is Fe. 2 O 3 and a coating consisting of iron calculated as the weight ratio of the zeolitic material to the first non-zeolitic oxide material in the catalyst is in the range of 5:1 to 20:1, more preferably in the range of 6.7:1 to 14.3:1, more preferably in the range of 8.3:1 to 12.5:1; The present invention relates to a catalyst in which the zeolitic material has a framework type selected from the group consisting of CHA, AEI, RTH, LEV, DDR, KFI, ERI, AFX, mixtures of two or more thereof, and mixed types of two or more thereof, more preferably selected from the group consisting of CHA, AEI, RTH, AFX, mixtures of two or more thereof, and mixed types of two or more thereof, more preferably selected from the group consisting of CHA and AEI, and the zeolitic material contained in the coating has framework type CHA.

[0030] In the context of the present invention, preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the first non-zeolitic oxide material consists of Al, Fe, and O. In other words, the first non-zeolitic oxide material preferably consists essentially of Al, Fe, and O, more preferably consists of Al, Fe, and O.

[0031] Preferably, 0 to 0.01 wt. %, more preferably 0 to 0.001 wt. %, more preferably 0 to 0.0001 wt. % of the first non-zeolitic oxide material is CeO 2 In other words, the non-zeolitic oxide material is preferably substantially free of cerium, and more preferably free of cerium.

[0032] Preferably, the coating further comprises a second non-zeolitic oxide material, more preferably comprising one or more of zirconia, alumina, titania, silica, and mixed oxides comprising two or more of Zr, Al, Ti, and Si, more preferably comprising one or more of silica, alumina, and zirconia, more preferably one or more of alumina and zirconia, more preferably zirconia.

[0033] Preferably, 95-100% by weight, more preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight of the second non-zeolitic oxide material in the coating is ZrO 2 In other words, the second non-zeolitic oxide material included in the coating preferably consists essentially of zirconia, and more preferably consists of zirconia.

[0034] Preferably, the coating comprises the second non-zeolitic oxide material in an amount in the range of 2 to 40% by weight, more preferably in the range of 2.5 to 30% by weight, more preferably in the range of 3 to 25% by weight, based on the weight of the zeolitic material, more preferably in the range of 3 to 10% by weight, more preferably in the range of 3.5 to 7% by weight, or the coating more preferably comprises the second non-zeolitic oxide material in an amount in the range of 15 to 25% by weight, more preferably in the range of 17 to 22% by weight, based on the weight of the zeolitic material.

[0035] More preferably, when the substrate of the catalyst of the present invention is a flow-through substrate, the coating comprises the second non-zeolitic oxide material in an amount in the range of 3 to 10 wt%, more preferably in the range of 3.5 to 7 wt%, based on the weight of the zeolitic material. Alternatively, when the substrate of the catalyst of the present invention is a wall-flow filter substrate, the coating comprises the second non-zeolitic oxide material in an amount in the range of 15 to 25 wt%, more preferably in the range of 17 to 22 wt%, based on the weight of the zeolitic material.

[0036] Preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the coating consists of the zeolitic material comprising copper, optionally iron, the first non-zeolitic oxide material comprising Fe and Al, more preferably the second non-zeolitic oxide material as defined above. In other words, it is preferred that the coating consists essentially of the zeolitic material comprising copper, optionally iron, the first non-zeolitic oxide material comprising Fe and Al, more preferably the second non-zeolitic oxide material as defined above, more preferably consists of copper.

[0037] Preferably, the substrate is made from one or more of cordierite, silicon carbide, and aluminum titanate, more preferably one or more of cordierite and silicon carbide, more preferably cordierite or silicon carbide.

[0038] Preferably, according to the first aspect of the invention, the substrate is a wall-flow filter substrate and the plurality of passages includes an inlet passage having an open inlet end and a closed outlet end, and an outlet passage having a closed inlet end and an open outlet end.

[0039] Preferably, the wall-flow filter substrate is made from one or more of silicon carbide and aluminum titanate, more preferably silicon carbide.

[0040] Preferably, the coating is located within the porous walls of the wall-flow filter substrate.

[0041] Preferably, according to the first aspect of the invention, the coating is homogeneously disposed along the substrate axial length. Alternatively, preferably, the amount of coating is greater in the intermediate zone of the substrate axial length compared to the amount present at each of the substrate inlet end and the substrate outlet end. More preferably, according to the first aspect of the invention, the amount of coating is greater in the intermediate zone of the substrate axial length compared to the amount present at each of the substrate inlet end and the substrate outlet end. This is illustrated by the following example.

[0042] Preferably, according to the first aspect, the substrate comprises a coating having a loading in the range of 0.5 to 3 g / in3, more preferably in the range of 0.75 to 2.5 g / in3, more preferably in the range of 1 to 2 g / in3.

[0043] Preferably, according to the second aspect of the invention, the substrate is a flow-through substrate. More preferably, the flow-through substrate is made of cordierite.

[0044] Preferably, according to the second aspect, the coating is located on a surface of an inner wall of the substrate.

[0045] Preferably, according to this second aspect, the coating is uniformly disposed along the axial length of the substrate.

[0046] Preferably, according to the second aspect, the substrate comprises a coating having a loading in the range of 0.75 to 5.5 g / in3, more preferably in the range of 1.25 to 4.5 g / in3, more preferably in the range of 2 to 4 g / in3.

[0047] In the context of the present invention, the coating is preferably disposed over 98-100%, more preferably 99-100% of the axial length of the substrate.

[0048] Preferably, the catalyst of the present invention comprises a substrate and a coating.

[0049] Furthermore, the present invention relates to a process for preparing a catalyst for selective catalytic reduction of NOx, more preferably a catalyst according to the present invention, comprising: (i) preparing a first aqueous mixture comprising water, a copper source, and optionally a precursor of a second non-zeolitic oxide component; (ii) mixing the first aqueous mixture obtained according to (i) with water and a zeolitic material, the zeolitic material being free of copper, the zeolitic material optionally comprising iron, to obtain a second aqueous mixture; (iii) mixing a first non-zeolitic oxide material containing Al and Fe with the second aqueous mixture prepared according to (ii), wherein at least 25 wt. % of the first non-zeolitic oxide material is Fe 2 O 3 and preferably adding water to obtain a third aqueous mixture. (iv) disposing the third aqueous mixture obtained according to (iii) onto a substrate comprising an inlet end, an outlet end, an axial length of the substrate extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough, and optionally drying the substrate comprising the mixture; (v) calcining the substrate obtained in (iv).

[0050] Preferably, the copper source included in the first aqueous mixture prepared in (i) is selected from the group consisting of copper acetate, copper nitrate, copper sulfate, copper formate, copper oxide, and mixtures of two or more thereof, more preferably selected from the group consisting of copper acetate, copper oxide, and mixtures thereof, more preferably copper oxide, more preferably CuO.

[0051] Preferably, the precursor of the second non-zeolitic oxide component included in the first aqueous mixture prepared in (i) is a zirconium salt or zirconium oxide, more preferably a zirconium salt, more preferably zirconium acetate.

[0052] Preferably, the first aqueous mixture prepared in (i) contains copper, calculated as CuO, in an amount in the range of 2 to 10 wt.%, more preferably in the range of 2.5 to 8 wt.%, more preferably in the range of 3 to 7 wt.%, more preferably in the range of 3.5 to 6 wt.%, based on the weight of the zeolitic material included in the second aqueous mixture prepared in (ii).

[0053] Preferably, (i) is (i.1) preparing a mixture comprising water and a copper source, the mixture further comprising an acid, more preferably an organic acid, more preferably acetic acid, and optionally, the mixture further comprising sucrose, more preferably; (i.2) adding a precursor of a second non-zeolitic oxide component to the mixture obtained according to (i.1) to obtain a first aqueous mixture.

[0054] With regard to (i.1), when the substrate used in (iv) is a wall-flow filter substrate, the mixture prepared according to (i.1) preferably comprises sucrose.

[0055] More preferably, sucrose is present in the mixture prepared in (i.1) in an amount in the range of 2 to 10 wt.%, more preferably in the range of 2.5 to 8 wt.%, more preferably in the range of 3 to 7 wt.%, more preferably in the range of 3.5 to 6 wt.%, based on the weight of zeolitic material contained in the second aqueous mixture prepared in (ii).

[0056] More preferably, the weight ratio of copper, calculated as CuO, to sucrose is in the range 2:1 to 1:2, more preferably in the range 1.5:1 to 1:1.5, more preferably in the range 1.2:1 to 1:1.2.

[0057] Preferably, 90-100% by weight, more preferably 93-99% by weight, more preferably 96-99% by weight of the copper source is present in an undissolved state in the mixture prepared in (i.1).

[0058] Preferably, the copper particles in the mixture according to (i.1) have a Dv90 in the range of 0.1 to 15 micrometers, more preferably in the range of 0.5 to 10 micrometers, more preferably in the range of 1 to 8 micrometers, more preferably in the range of 3 to 7 micrometers, Dv90 preferably determined as described in Reference Example 3.

[0059] Preferably, the second mixture obtained in (ii) has a solids content in the range of 15 to 50% by weight, more preferably in the range of 20 to 45% by weight, more preferably in the range of 30 to 40% by weight, based on the weight of the second mixture.

[0060] Preferably, the particles of the zeolitic material in the second mixture have a Dv50 in the range of 0.5 to 5 micrometers, preferably in the range of 0.75 to 3 micrometers; Dv90 is preferably determined as described in Example 3.

[0061] Preferably, (ii) is mixing the first aqueous mixture obtained according to (ii.1)(i) with water and a zeolitic material, wherein the zeolitic material does not comprise copper, and the zeolitic material optionally comprises iron; (ii.2) milling the resulting mixture (ii.1), more preferably until particles of the mixture have a Dv90 in the range of 0.5 to 8 micrometers, more preferably in the range of 1 to 5 micrometers, more preferably in the range of 1.5 to 4 micrometers, the Dv90 being preferably determined as described in Reference Example 3, to obtain a third aqueous mixture, More preferably, the particles of the mixture have a Dv99 in the range of 1.5 to 12 micrometers, more preferably in the range of 2 to 10 micrometers, more preferably in the range of 3 to 7 micrometers, Dv99 being preferably determined as described in Reference Example 3 to obtain the second aqueous mixture.

[0062] Preferably, the particles of the first non-zeolitic oxide material mixed into the second aqueous mixture according to (ii) have a Dv50 in the range of 3 to 15 micrometers, more preferably in the range of 6 to 12 micrometers, with Dv50 preferably determined as described in Reference Example 3.

[0063] Preferably, the particles of the first non-zeolitic oxide material mixed into the second aqueous mixture according to (ii) have a Dv90 in the range of 8 to 40 micrometers, more preferably in the range of 15 to 25 micrometers, with Dv90 preferably determined as described in Reference Example 3.

[0064] Preferably, the particles of the first non-zeolitic oxide material mixed into the second aqueous mixture according to (ii) have a Dv99 in the range of 10 to 50 micrometers, more preferably in the range of 20 to 30 micrometers, with Dv99 preferably determined as described in Reference Example 3.

[0065] Preferably, the mixture prepared in (iii) comprises the first non-zeolitic oxide material in an amount in the range of 5 to 20 wt.%, more preferably in the range of 7 to 15 wt.%, more preferably in the range of 8 to 12 wt.%, based on the weight of the zeolitic material.

[0066] Preferably, the third aqueous mixture obtained in (iii) has a solids content in the range of 15 to 50% by weight, more preferably in the range of 25 to 48% by weight, more preferably in the range of 28 to 40% by weight, based on the weight of the third aqueous mixture.

[0067] Preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the third aqueous mixture obtained according to (iii) consists of water, optionally a zeolitic material comprising iron, a copper source, a first non-zeolitic oxide material comprising Al and Fe, more preferably a precursor of a second non-zeolitic oxide material. In other words, the third aqueous mixture obtained according to (iii) preferably consists essentially, more preferably of water, The zeolitic material optionally comprises iron, a source of copper, a first non-zeolitic oxide material comprising Al and Fe, and more preferably a precursor of a second non-zeolitic oxide material.

[0068] Preferably, the disposing of the third mixture according to (iv) is carried out by spraying the mixture onto the substrate or by immersing the substrate in the mixture, more preferably by immersing the substrate in the mixture.

[0069] Preferably, the third aqueous mixture obtained according to (iii) is disposed over x% of the axial length of the substrate from the inlet end to the outlet end of the substrate, or from the outlet end to the inlet end of the substrate, according to (iv), where x is in the range of 95 to 100, more preferably in the range of 98 to 100, more preferably in the range of 99 to 100.

[0070] Preferably, the substrate in (iv) is a flow-through substrate, more preferably the substrate is made from one or more of cordierite, silicon carbide, and aluminum titanate, more preferably one or more of cordierite and silicon carbide, more preferably cordierite.

[0071] Preferably, (iv) is (iii) disposing the third aqueous mixture obtained on a flow-through substrate from the inlet end to the outlet end of the substrate, or from the outlet end to the inlet end of the substrate, more preferably from the inlet end to the outlet end, over 95-100%, more preferably 98-100%, more preferably 99-100% of the axial length of the substrate; and drying the substrate containing the mixture.

[0072] Preferably, the substrate in (iv) is a wall-flow filter substrate, the plurality of passages including an inlet passage having an open inlet end and a closed outlet end, and an outlet passage having a closed inlet end and an open outlet end, the substrate more preferably being made from one or more of cordierite, silicon carbide, and aluminum titanate, more preferably one or more of silicon carbide and alumina titanate.

[0073] Preferably, disposing according to (iv) comprises (iv.1) disposing a first portion of the third aqueous mixture obtained in (iii) on a wall-flow filter substrate over 40-85%, more preferably 55-80%, more preferably 65-75% of the substrate axial length from the outlet end to the inlet end of the substrate; and drying the substrate containing the first portion of the third aqueous mixture. (iv.2) disposing a second portion of the third aqueous mixture obtained in (iii) on a substrate comprising a first portion of the third aqueous mixture obtained in (iv.1) over 40 to 85%, more preferably 55 to 80%, more preferably 65 to 75% of the axial length of the substrate from the inlet end to the outlet end of the substrate, and optionally drying the substrate comprising the first and second portions of the third aqueous mixture.

[0074] Alternatively, it is conceivable that the substrate is coated with the first portion over 100% of the axial length of the substrate from the inlet or outlet end of the substrate, and the substrate is coated with the second portion over 100% of the axial length of the substrate from the other of the inlet or outlet end of the substrate. It is also conceivable that in (iv.1) the disposition is rather from the inlet end towards the outlet end, and in (iv.2) the disposition is rather from the outlet end towards the inlet end.

[0075] In the context of the present invention, the drying according to (iv) is preferably carried out in a gas atmosphere having a temperature in the range from 60 to 300° C., more preferably in the range from 90 to 150° C., the gas atmosphere more preferably comprising oxygen.

[0076] When (iv) comprises (iv.1) and (iv.2), drying according to (iv.1) and / or (iv.2), more preferably according to (iv.1) and (iv.2), is preferably carried out in a gas atmosphere having a temperature in the range from 60 to 300°C, more preferably in the range from 90 to 150°C.

[0077] Preferably, the drying according to (iv) is carried out in a gas atmosphere for a duration ranging from 10 minutes to 4 hours, more preferably from 20 minutes to 2 hours.

[0078] If (iv) comprises (iv.1) and (iv.2), drying according to (iv.1) and / or (iv.2), more preferably according to (iv.1) and (iv.2), is preferably carried out in a gas atmosphere for a duration in the range from 10 minutes to 4 hours, more preferably in the range from 20 minutes to 2 hours.

[0079] Preferably, the firing according to (v) is carried out in a gas atmosphere having a temperature in the range of 300 to 900° C., more preferably in the range of 400 to 650° C., more preferably in the range of 400 to 500° C., the gas atmosphere more preferably containing oxygen.

[0080] Preferably, the calcination according to (v) is carried out in a gas atmosphere for a duration ranging from 0.1 to 4 hours, more preferably from 0.5 to 2.5 hours.

[0081] Preferably, the process of the present invention consists of steps (i), (ii), (iii), (iv) and (v).

[0082] The present invention further relates to a catalyst for the selective catalytic reduction of NOx obtainable or obtained by the process according to the invention, said catalyst being preferably as defined above.

[0083] The present invention further relates to an exhaust gas treatment system for treating exhaust gas from a compression ignition engine, more preferably a diesel engine, the exhaust gas treatment system having an upstream end for introducing the exhaust gas stream into the exhaust gas treatment system, The exhaust gas treatment system comprises: A catalyst according to the present invention; The present invention relates to an exhaust gas treatment system comprising one or more of a diesel oxidation catalyst, a selective catalytic reduction catalyst, an ammonia oxidation catalyst, a NOx trap, and a particulate filter. Preferably, the system comprises a diesel oxidation catalyst, and the catalyst according to the invention is located downstream of the diesel oxidation catalyst.

[0084] Preferably, the system comprises a diesel oxidation catalyst, a selective catalytic reduction catalyst on a filter, and a catalyst according to the present invention; a diesel oxidation catalyst is upstream of a selective catalytic reduction catalyst (SCRoF) on the filter, and a catalyst according to the invention is downstream of the SCRoF catalyst; The system further comprises a selective catalytic reduction catalyst or an ammonia oxidation catalyst downstream of the catalyst according to the invention.

[0085] Alternatively, preferably, the system comprises a diesel oxidation catalyst, a selective catalytic reduction catalyst and a catalyst according to the invention, the diesel oxidation catalyst being upstream of the selective catalytic reduction (SCR) catalyst and the catalyst according to the invention being downstream of the SCR catalyst; The system further comprises a selective catalytic reduction catalyst or an ammonia oxidation catalyst downstream of the catalyst according to the invention.

[0086] Alternatively, preferably, the system comprises a diesel oxidation catalyst, a selective catalytic reduction catalyst and a catalyst according to the invention, the diesel oxidation catalyst being upstream of the catalyst according to the invention and the selective catalytic reduction (SCR) catalyst being downstream of the catalyst according to the invention; The system further comprises an additional selective catalytic reduction catalyst or an ammonia oxidation catalyst downstream of the SCR catalyst.

[0087] Alternatively, preferably, the system of the present invention comprises a diesel oxidation catalyst, a selective catalytic reduction catalyst (SCRoF) on a filter, a catalyst according to the present invention, the diesel oxidation catalyst being upstream of the catalyst according to the present invention and the SCRoF catalyst being downstream of the catalyst according to the present invention, The system further comprises a selective catalytic reduction catalyst or an ammonia oxidation catalyst downstream of the SCRoF catalyst.

[0088] The present invention further relates to the use of the catalyst according to the invention for the selective catalytic reduction of NOx.

[0089] The present invention further provides a method for selective catalytic reduction of NOx, comprising the steps of: (1) providing an exhaust gas stream, preferably an exhaust gas stream exiting a diesel engine; (2) contacting the exhaust gas stream provided in (1) with a catalyst for selective catalytic reduction of NOx according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0090] The present invention is further illustrated by the following set of embodiments and combinations of embodiments resulting from dependencies and reverse references as indicated. In particular, in each case where a range of embodiments is mentioned, for example, in the context of a term such as "any one catalyst of embodiments 1-4", it is meant that all embodiments within this range are explicitly disclosed to those skilled in the art, that is, the expression of this term is understood by those skilled in the art to be synonymous with "any one catalyst of embodiments 1, 2, 3, and 4". Furthermore, it is clearly noted that the following set of embodiments represents a properly structured part of the general description directed to the preferred aspects of the present invention, and thus properly supports but does not represent the scope of the claims of the present invention.

[0091] 1. A catalyst for selective catalytic reduction of NOx, a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough; A coating comprising a zeolitic material and a first non-zeolitic oxide material comprising copper, iron and aluminum, wherein at least 25% by weight of the first non-zeolitic oxide material is Fe. 2 O 3 and a catalyst comprising:

[0092] 2. The zeolite material included in the coating is ABW, ACO, AEI, AEL, AEN, AET, AFG, AFI, AFN, AFO, AFR, AFS, AFT, AFV, AFX, AFY, AHT, ANA, APC, APD, AST, ASV, ATN, ATO, ATS, ATT, ATV, AVL, AWO, AWW, BCT, BE A, BEC, BIK, BOF, BOG, BOZ, BPH, BRE, BSV, CAN, CAS, CDO, CFI, CGF, CGS, CHA, -CHI, -CLO, CON, CSV, CZP, DAC, DDR, DFO, DFT, DOH, DON, EAB, EDI, EEI, EMT, EON, EPI, ERI, ESV, ETR, EUO, * -EWT, EZT, FAR, FAU, FER, FRA, GIS, GIU, GME, GON, GOO, HEU, IFO, IFR, -IFU, IFW, IFY, IHW, IMF, IRN, IRR, -IRY, ISV, ITE, ITG, ITH, * -ITN, ITR, ITT, -ITV, ITW, IWR, IWS, IWV, IWW, JBW, JNT, JOZ, JRY, JSN, JSR, JST, JSW, KFI, LAU, LEV , LIO, -LIT, LOS, LOV, LTA, LTF, LTJ, LTL, LTN, MAR, MAZ, MEI, MEL, MEP, MER, MFI, MFS, MON, MOR, MOZ, *MRE, MSE, MSO, MTF, MTN, MTT, MTW, MVY, MWF, MWW, NAB, NAT, NES, NON, NPO, NPT, NSI, OBW, OFF, OKO, OSI, OSO, OWE, -PAR, PAU, PCR, PHI, PON, PO S, PSI, PUN, RHO, -RON, RRO, RSN, RTE, RTH, RUT, RWR, RWY, SAF, SAO, SAS, SAT, SAV, SBE, SBN, SBS, SBT, SEW, SFE, SFF, SFG, SFH, SFN, SFO, SFS, * SFV, SFW, SGT, SIV, SOD, SOF, SOS, SSF, * -SSO, SSY, STF, STI, * Catalyst according to embodiment 1, wherein the zeolitic material comprised in the coating has a framework type selected from the group consisting of STO, STT, STW, -SVR, SVV, SZR, TER, THO, TOL, TON, TSC, TUN, UEI, UFI, UOS, UOV, UOZ, USI, UTL, UWY, VET, VFI, VNI, VSV, WEI, -WEN, YUG, ZON, mixtures of two or more thereof, and mixed types of two or more thereof, preferably selected from the group consisting of CHA, AEI, RTH, LEV, DDR, KFI, ERI, AFX, mixtures of two or more thereof, and mixed types of two or more thereof, more preferably selected from the group consisting of CHA, AEI, RTH, AFX, mixtures of two or more thereof, and mixed types of two or more thereof, more preferably selected from the group consisting of CHA and AEI, more preferably the zeolitic material comprised in the coating has framework type CHA.

[0093] 3. 95 to 100% by weight, preferably 98 to 100% by weight, more preferably 99 to 100% by weight of the framework structure of the zeolite material is composed of Si, Al and O, and the molar ratio of the framework structure to SiO 2 :Al 2 O 3 The molar ratio of Si to Al calculated as above is preferably in the range of 2:1 to 30:1, more preferably in the range of 5:1 to 28:1, and more preferably in the range of 8:1 to 26:1, More preferably, the ratio is in the range of 10:1 to 19:1, more preferably in the range of 12:1 to 18:1, or More preferably, the catalyst according to embodiment 1 or 2 is in the range of 20:1 to 25:1.

[0094] 4. The catalyst according to any one of the preceding embodiments, wherein the zeolitic material comprised in the coating, preferably a zeolitic material having framework type CHA, has an average crystallite size, as measured by scanning electron microscopy, of at least 0.1 micrometers, preferably in the range of 0.1 to 3.0 micrometers, more preferably in the range of 0.3 to 1.5 micrometers, more preferably in the range of 0.4 to 1.0 micrometers.

[0095] 5. The catalyst according to any one of the preceding embodiments, wherein the amount of copper contained in the coating, calculated as CuO, is in the range of 2 to 10 wt. %, preferably in the range of 2.5 to 8 wt. %, more preferably in the range of 3 to 7 wt. %, more preferably in the range of 3.5 to 6 wt. %, based on the weight of the zeolitic material, and the zeolitic material contained in the coating preferably comprises copper.

[0096] 6. The zeolite material contains iron, and the Fe 2 O 3 6. The catalyst according to any one of the preceding embodiments, wherein the amount of iron, calculated as , is in the range of 0.1 to 1.5 wt.%, preferably in the range of 0.15 to 1.25 wt.%, more preferably in the range of 0.25 to 1 wt.%, more preferably in the range of 0.3 to 0.8 wt.%, based on the weight of the zeolitic material.

[0097] 7. The catalyst of any one of the preceding embodiments, wherein the coating comprises a loading of zeolite material in the range of 0.25 to 5 g / in3, preferably in the range of 0.75 to 3 g / in3, more preferably in the range of 1 to 2.5 g / in3, more preferably in the range of 1.25 to 2.2 g / in3.

[0098] 8. The zeolite material contained in the coating, preferably having framework type CHA, has a viscosity of 50 to 900 m, determined as described in Reference Example 1. 2 / g, preferably 150 to 700m 2 / g, more preferably 250 to 650 m 2 The catalyst of any one of the preceding embodiments, having a BET specific surface area in the range of 1 / g.

[0099] 9. The catalyst according to any one of the preceding embodiments, wherein 50-92% by weight, preferably 65-90% by weight, more preferably 70-85% by weight of the coating consists of zeolitic material.

[0100] 10. 25-65 wt. %, preferably 30-60 wt. %, more preferably 40-55 wt. %, more preferably 45-55 wt. % of the first non-zeolitic oxide material is Fe 2 O 3 10. The catalyst of any one of the preceding embodiments, wherein the iron consists essentially of iron, calculated as:

[0101] 11. 35 to 75% by weight, preferably 40 to 70% by weight, more preferably 45 to 60% by weight, more preferably 45 to 55% by weight of the first non-zeolitic oxide material is Al 2 O 3 11. The catalyst of any one of the preceding embodiments, wherein the aluminum content is calculated as:

[0102] 12. The first non-zeolitic oxide material is one or more of a mixture of oxides containing Al and Fe, a mixed oxide containing Al and Fe, and an oxide of Al impregnated with Fe, preferably one or more of a mixed oxide containing Al and Fe, and an oxide of Al impregnated with Fe; The first non-zeolite oxide material is 50 to 300 m 2 / g, more preferably 80 to 160 m 2 The catalyst according to any one of the preceding embodiments, having a BET specific surface area in the range of 1 / g.

[0103] 13. The catalyst according to any one of the preceding embodiments, wherein the coating comprises the first non-zeolitic oxide material in an amount in the range of 5 to 20% by weight, preferably in the range of 7 to 15% by weight, more preferably in the range of 8 to 12% by weight, based on the weight of the zeolitic material.

[0104] 14. The catalyst according to any one of the preceding embodiments, wherein 99-100% by weight, preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the first non-zeolitic oxide material consists of Al, Fe, and O.

[0105] 15. 0-0.01 wt. %, preferably 0-0.001 wt. %, more preferably 0-0.0001 wt. % of the first non-zeolitic oxide material is CeO 2 15. The catalyst of any one of the preceding embodiments, wherein cerium is present in an amount calculated as:

[0106] 16. The coating further comprises a second non-zeolitic oxide material, the second non-zeolitic oxide material preferably comprising one or more of zirconia, alumina, titania, silica, and mixed oxides comprising two or more of Zr, Al, Ti, and Si, more preferably comprising one or more of silica, alumina, and zirconia, more preferably comprising one or more of alumina and zirconia, more preferably comprising zirconia; Preferably, 95-100% by weight, more preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight of the second non-zeolitic oxide material in the coating is ZrO 2 16. The catalyst of any one of the preceding embodiments, wherein zirconium is present in an amount calculated as:

[0107] 17. The catalyst according to any one of the preceding embodiments, wherein the coating comprises a second non-zeolitic oxide material in an amount in the range of 2 to 40% by weight, preferably in the range of 2.5 to 30% by weight, more preferably in the range of 3 to 25% by weight, based on the weight of the zeolitic material.

[0108] 18. The catalyst according to any one of the preceding embodiments, wherein 98-100% by weight, preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the coating consists of a zeolitic material comprising copper, optionally iron, a first non-zeolitic oxide material comprising Fe and Al, preferably a second non-zeolitic oxide material as defined in embodiment 16 or 17.

[0109] 19. The catalyst according to any one of the preceding embodiments, wherein the substrate is made of one or more of cordierite, silicon carbide, and aluminum titanate, preferably one or more of cordierite and silicon carbide, more preferably cordierite or silicon carbide.

[0110] 20. The catalyst of any one of the preceding embodiments, wherein the substrate is a wall-flow filter substrate, the plurality of passages including an inlet passage having an open inlet end and a closed outlet end, and an outlet passage having a closed inlet end and an open outlet end, and the wall-flow filter substrate is preferably made from one or more of silicon carbide, aluminum titanate, more preferably silicon carbide.

[0111] 21. The catalyst of embodiment 20, wherein the coating is located within the porous walls of a wall-flow filter substrate.

[0112] 22. The catalyst of embodiment 20 or 21, wherein the coating is homogeneously disposed along the axial length of the substrate or the amount of coating is greater in the middle zone of the axial length of the substrate compared to the amount present at each of the inlet end of the substrate and the outlet end of the substrate, preferably the amount of coating is greater in the middle zone of the axial length of the substrate compared to the amount present at each of the inlet end of the substrate and the outlet end of the substrate.

[0113] 23. The catalyst of any one of embodiments 20 to 22, wherein the substrate comprises a coating with a loading in the range of 0.5 to 3 g / in3, preferably in the range of 0.75 to 2.5 g / in3, preferably in the range of 1 to 2 g / in3.

[0114] 24. The catalyst according to any one of the preceding embodiments, wherein the substrate is a flow-through substrate, the flow-through substrate being preferably made of cordierite.

[0115] 25. The catalyst of embodiment 24, wherein the coating is located on a surface of an inner wall of the substrate.

[0116] 26. The catalyst of embodiment 24 or 25, wherein the coating is disposed uniformly along the axial length of the substrate.

[0117] 27. The catalyst of any one of embodiments 24 to 26, wherein the substrate comprises a coating with a loading in the range of 0.75 to 5.5 g / in3, preferably in the range of 1.25 to 4.5 g / in3, more preferably in the range of 2 to 4 g / in3.

[0118] 28. The catalyst according to any one of the preceding embodiments, wherein the coating is disposed over 98-100%, preferably 99-100%, of the axial length of the substrate.

[0119] 29. The catalyst according to any one of the preceding embodiments, comprising a substrate and a coating.

[0120] 30. A process for preparing a catalyst for selective catalytic reduction of NOx, preferably according to any one of embodiments 1 to 29, comprising: (i) preparing a first aqueous mixture comprising water, a copper source, and optionally a precursor of a second non-zeolitic oxide component; (ii) mixing the first aqueous mixture obtained according to (i) with water and a zeolitic material, the zeolitic material being free of copper, the zeolitic material optionally comprising iron, to obtain a second aqueous mixture; (iii) mixing a first non-zeolitic oxide material containing Al and Fe with the second aqueous mixture prepared according to (ii), wherein at least 25 wt. % of the first non-zeolitic oxide material is Fe 2 O 3 and preferably adding water to obtain a third aqueous mixture. (iv) disposing the third aqueous mixture obtained according to (iii) onto a substrate comprising an inlet end, an outlet end, an axial length of the substrate extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough, and optionally drying the substrate comprising the mixture; (v) calcining the substrate obtained in (iv).

[0121] 31. The process of embodiment 30, wherein the copper source included in the first aqueous mixture prepared in (i) is selected from the group consisting of copper acetate, copper nitrate, copper sulfate, copper formate, copper oxide, and mixtures of two or more thereof, preferably selected from the group consisting of copper acetate, copper oxide, and mixtures thereof, more preferably copper oxide, more preferably CuO.

[0122] 32. The process of embodiment 30 or 31, wherein the precursor of the second non-zeolitic oxide component included in the first aqueous mixture prepared in (i) is a zirconium salt or zirconium oxide, preferably a zirconium salt, more preferably zirconium acetate.

[0123] 33. The process of any one of embodiments 30 to 32, wherein the first aqueous mixture prepared in (i) contains copper, calculated as CuO, in an amount in the range of 2 to 10 wt.%, preferably in the range of 2.5 to 8 wt.%, more preferably in the range of 3 to 7 wt.%, more preferably in the range of 3.5 to 6 wt.%, based on the weight of the zeolitic material contained in the second aqueous mixture prepared in (ii).

[0124] 34.(i) is (i.1) preparing a mixture comprising water and a copper source, the mixture preferably further comprising an acid, more preferably an organic acid, more preferably acetic acid, the mixture optionally preferably further comprising sucrose; (i.2) adding a precursor of a second non-zeolitic oxide component to the mixture obtained according to (i.1) to obtain a first aqueous mixture.

[0125] 35. The process of embodiment 34, wherein 90 to 100% by weight, preferably 93 to 99% by weight, more preferably 96 to 99% by weight, of the copper source is present in an undissolved state in the mixture prepared in (i.1).

[0126] 36. The process according to embodiment 35, wherein the copper particles in the mixture according to (i.1) have a Dv90 in the range of 0.1 to 15 micrometers, preferably in the range of 0.5 to 10 micrometers, more preferably in the range of 1 to 8 micrometers, more preferably in the range of 3 to 7 micrometers, wherein Dv90 is preferably determined as described in Reference Example 3.

[0127] 37. The process according to any one of embodiments 30 to 36, wherein the second mixture obtained in (ii) has a solids content in the range of 15 to 50% by weight, preferably in the range of 20 to 45% by weight, more preferably in the range of 30 to 40% by weight, based on the weight of the second mixture.

[0128] 38. The process according to any one of embodiments 30 to 37, wherein the particles of the zeolite material in the second mixture have a Dv50 in the range of 0.5 to 5 micrometers, preferably in the range of 0.75 to 3 micrometers, and a Dv90, preferably determined as described in Reference Example 3.

[0129] 39.(ii) is mixing the first aqueous mixture obtained according to (ii.1)(i) with water and a zeolitic material, wherein the zeolitic material does not comprise copper, and the zeolitic material optionally comprises iron; (ii.2) milling the resulting mixture (ii.1), preferably until particles of the mixture have a Dv90 in the range of 0.5 to 8 micrometers, more preferably in the range of 1 to 5 micrometers, more preferably in the range of 1.5 to 4 micrometers, the Dv90 being preferably determined as described in Reference Example 3, to obtain a third aqueous mixture, 39. The process of any one of embodiments 30-38, comprising: grinding the mixture to obtain a second aqueous mixture, more preferably the particles of the mixture having a Dv99 in the range of 1.5 to 12 micrometers, more preferably in the range of 2 to 10 micrometers, more preferably in the range of 3 to 7 micrometers, the Dv99 being preferably determined as described in Reference Example 3.

[0130] 40. The process according to any one of embodiments 30 to 39, wherein the particles of the first non-zeolitic oxide material mixed into the second aqueous mixture according to (ii) have a Dv90 in the range of 8 to 40 micrometers, preferably in the range of 15 to 25 micrometers, the Dv90 being preferably determined as described in Reference Example 3.

[0131] 41. The process according to any one of embodiments 30 to 40, wherein the particles of the first non-zeolitic oxide material mixed into the second aqueous mixture according to (ii) have a Dv99 in the range of 10 to 50 micrometers, preferably in the range of 20 to 30 micrometers, and the Dv99 is preferably determined as described in Reference Example 3.

[0132] 42. The process according to any one of embodiments 30 to 41, wherein the particles of the first non-zeolitic oxide material mixed into the second aqueous mixture according to (ii) have a Dv50 in the range of 3 to 15 micrometers, preferably in the range of 6 to 12 micrometers, the Dv50 being preferably determined as described in Reference Example 3.

[0133] 43. The process of any one of embodiments 30 to 42, wherein the mixture prepared according to (iii) comprises the first non-zeolitic oxide material in an amount in the range of 5 to 20 wt.%, preferably in the range of 7 to 15 wt.%, more preferably in the range of 8 to 12 wt.%, based on the weight of the zeolitic material.

[0134] 44. The process according to any one of embodiments 30 to 43, wherein the third aqueous mixture obtained according to (iii) has a solids content in the range of 15 to 50% by weight, more preferably in the range of 25 to 48% by weight, more preferably in the range of 28 to 40% by weight, based on the weight of the third aqueous mixture.

[0135] 45. The process according to any one of embodiments 30 to 44, wherein 98 to 100% by weight, preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight, more preferably 99.9 to 100% by weight of the third aqueous mixture obtained according to (iii) consists of water, and the zeolitic material optionally comprises iron, a source of copper, a first non-zeolitic oxide material comprising Al and Fe, preferably a precursor of a second non-zeolitic oxide material.

[0136] 46. ​​The process according to any one of embodiments 30 to 45, wherein the disposing of the third mixture according to (iv) is carried out by spraying the mixture onto the substrate or by immersing the substrate in the mixture, preferably by immersing the substrate in the mixture.

[0137] 47. The process of any one of embodiments 30 to 46, wherein the third aqueous mixture obtained according to (iii) is disposed according to (iv) over x% of the axial length of the substrate from the inlet end to the outlet end of the substrate, or from the outlet end to the inlet end of the substrate, where x is in the range of 95 to 100, preferably in the range of 98 to 100, more preferably in the range of 99 to 100.

[0138] 48. The process of any one of embodiments 30 to 47, wherein the substrate in (iv) is a flow-through substrate, and the substrate is preferably made from one or more of cordierite, silicon carbide, and aluminum titanate, preferably one or more of cordierite and silicon carbide, more preferably cordierite.

[0139] 49.(iv) 49. The process of embodiment 48, comprising disposing the third aqueous mixture obtained according to (iii) onto a flow-through substrate from the inlet end towards the outlet end of the substrate or from the outlet end towards the inlet end of the substrate, preferably from the inlet end towards the outlet end, across 95-100%, preferably 98-100%, more preferably 99-100% of the axial length of the substrate, and drying the substrate containing the mixture.

[0140] 50. The process of any one of embodiments 30-47, wherein the substrate in (iv) is a wall-flow filter substrate, the plurality of passages including an inlet passage having an open inlet end and a closed outlet end, and an outlet passage having a closed inlet end and an open outlet end, and the substrate is preferably made from one or more of cordierite, silicon carbide, and aluminum titanate, more preferably one or more of silicon carbide and alumina titanate.

[0141] 51.(iv) is to be placed in accordance with (iv.1) disposing a first portion of the third aqueous mixture obtained in (iii) on a wall-flow filter substrate over 40-85%, preferably 55-80%, more preferably 65-75% of the substrate axial length from the outlet end to the inlet end of the substrate; and drying the substrate containing the first portion of the third aqueous mixture. 51. The process of embodiment 50, comprising: (iv.2) disposing a second portion of the third aqueous mixture obtained in (iii) on a substrate comprising the first portion of the third aqueous mixture obtained in (iv.1) over 40-85%, preferably 55-80%, more preferably 65-75% of the axial length of the substrate from the inlet end to the outlet end of the substrate; and optionally drying the substrate comprising the first and second portions of the third aqueous mixture.

[0142] 52. Drying according to (iv) is carried out in a gas atmosphere having a temperature in the range of 60 to 300 ° C, preferably in the range of 90 to 150 ° C, the gas atmosphere preferably containing oxygen; 52. The process according to any one of embodiments 30 to 51, wherein the drying according to (iv) is carried out in a gas atmosphere for a duration preferably in the range of 10 minutes to 4 hours, more preferably in the range of 20 minutes to 2 hours.

[0143] 53. The calcination according to (v) is carried out in a gas atmosphere having a temperature in the range of 300 to 900 ° C, preferably in the range of 400 to 650 ° C, more preferably in the range of 400 to 500 ° C, the gas atmosphere preferably containing oxygen; 53. The process according to any one of embodiments 30 to 52, wherein the calcination according to (v) is carried out in a gas atmosphere for a duration preferably in the range of 0.1 to 4 hours, more preferably in the range of 0.5 to 2.5 hours.

[0144] 54. The process of any one of embodiments 19 to 53, comprising (i), (ii), (iii), (iv), and (v).

[0145] 55. A catalyst for the selective catalytic reduction of NOx, obtainable or obtained by a process according to any one of embodiments 30 to 54.

[0146] 56. An exhaust gas treatment system for treating exhaust gas from a compression ignition engine, preferably a diesel engine, the exhaust gas treatment system having an upstream end for introducing the exhaust gas stream into the exhaust gas treatment system, the exhaust gas treatment system comprising a catalyst as described in any one of embodiments 1 to 29 and 55, and one or more of a diesel oxidation catalyst, a selective catalytic reduction catalyst, an ammonia oxidation catalyst, a NOx trap, and a particulate filter.

[0147] 57. The system of embodiment 56, comprising a diesel oxidation catalyst, wherein the catalyst of any one of embodiments 1 to 29 and 55 is located downstream of the diesel oxidation catalyst.

[0148] 58. A diesel oxidation catalyst, a selective catalytic reduction catalyst on a filter, comprising the catalyst according to any one of embodiments 1-29 and 55, wherein the diesel oxidation catalyst is upstream of the selective catalytic reduction catalyst on a filter (SCRoF), and the catalyst according to any one of embodiments 1-29 and 55 is downstream of the SCRoF catalyst; The system of embodiment 56 or 57, wherein the system further comprises a selective catalytic reduction catalyst or an ammonia oxidation catalyst downstream of the catalyst of any one of embodiments 1 to 29 and 55.

[0149] 59. A diesel oxidation catalyst, a selective catalytic reduction catalyst, comprising the catalyst of any one of embodiments 1-29 and 55, wherein the diesel oxidation catalyst is upstream of a selective catalytic reduction (SCR) catalyst, and the catalyst of any one of embodiments 1-29 and 55 is downstream of the SCR catalyst; The system of embodiment 56 or 57, wherein the system further comprises a selective catalytic reduction catalyst or an ammonia oxidation catalyst downstream of the catalyst of any one of embodiments 1 to 29 and 55.

[0150] 60. A diesel oxidation catalyst, a selective catalytic reduction catalyst, comprising the catalyst of any one of embodiments 1-29 and 55, wherein the diesel oxidation catalyst is upstream of the catalyst of any one of embodiments 1-29 and 55, and a selective catalytic reduction (SCR) catalyst is downstream of the catalyst of any one of embodiments 1-29 and 55; 58. The system of embodiment 56 or 57, wherein the system further comprises an additional selective catalytic reduction catalyst or an ammonia oxidation catalyst downstream of the SCR catalyst.

[0151] 61. A diesel oxidation catalyst, a selective catalytic reduction catalyst (SCRoF) on a filter, comprising the catalyst according to any one of embodiments 1 to 29 and 55, wherein the diesel oxidation catalyst is upstream of the catalyst according to any one of embodiments 1 to 29 and 55, and the SCRoF catalyst is downstream of the catalyst according to any one of embodiments 1 to 29 and 55; 58. The system of embodiment 56 or 57, wherein the system further comprises a selective catalytic reduction catalyst or an ammonia oxidation catalyst downstream of the SCRoF catalyst.

[0152] 62. Use of a catalyst according to any one of embodiments 1 to 29 and 55 for selective catalytic reduction of NOx.

[0153] 63. A method for selective catalytic reduction of NOx, comprising: (1) providing an exhaust gas stream, preferably an exhaust gas stream exiting a diesel engine; (2) contacting the exhaust gas stream provided in (1) with a catalyst for selective catalytic reduction of NOx as described in any one of embodiments 1 to 29 and 55.

[0154] Furthermore, it should be clearly noted that the above series of embodiments represents a properly structured portion of the general description directed to preferred aspects of the present invention and thus properly supports the claims of the present invention, but does not represent the same.

[0155] Systems according to the present invention are listed in the table below.

[0156] [Table 1]

[0157] Catalyst 1 is located upstream of catalyst 2, which is located upstream of catalyst 3, which is located upstream of catalyst 4. In the above table, "Catalyst" refers to a catalyst according to the present invention. Also, "DOC" refers to a diesel oxidation catalyst, "SCR" refers to a selective catalytic reduction catalyst, and "AMOx" refers to an ammonia oxidation catalyst. "Catalyst as SCR" means that the catalyst according to the present invention is an SCR catalyst on a flow-through substrate, and "Catalyst as SCRoF" means that the catalyst according to the present invention is an SCR catalyst on a wall-flow filter substrate.

[0158] In the context of the present invention, the term "SCR" refers to selective catalytic reduction catalyst and the term "SCRoF" refers to selective catalytic reduction catalyst on a wall-flow filter substrate.

[0159] In the context of the present invention, the catalyst of the present invention is preferably located downstream of a diesel engine.

[0160] Furthermore, in the context of the present invention, the term "loading of a given component / coating" (expressed in g / cubic inch or g / cubic foot) refers to the mass of that component / coating per volume of substrate, the volume being the volume defined by the cross-sectional area of ​​the substrate multiplied by the axial length of the substrate on which that component / coating resides. For example, when referring to a loading of a first coating that extends over x% of the substrate axial length and has a loading of X g / cubic inch, the loading refers to X grams of first coating per x% of the total substrate volume (in cubic inches).

[0161] Furthermore, in the context of the present invention, the term "based on the weight of the zeolitic material" refers to the weight of the zeolitic material alone, and is meant not to include copper.

[0162] Furthermore, in the context of the present invention, the term "X is one or more of A, B, and C" (X is a given feature and each of A, B, and C represents a specific realization of that feature) should be understood as disclosing that X is either A, or B, or C, or A and B, or A and C, or B and C, or A and B and C. In this regard, it should be noted that a person skilled in the art can translate the above abstract terms into concrete examples. For example, X is a chemical element and A, B, and C are specific elements such as Li, Na, and K, or X is a temperature and A, B, and C are specific temperatures such as 10°C, 20°C, and 30°C. In this regard, it is further noted that one of skill in the art may extend the above terms to less specific recognition of the feature (e.g., "X is one or more of A and B" discloses that X is either A, or B, or A and B), or more specific recognition of the feature (e.g., "X is one or more of A, B, C, and D" discloses that X is either A, or B, or C, or D, or A and B, or A and C, or A and D, or B and C, or B and D, or C and D, or A and B and C, or A and B and D, or B and C and D, or A and B and C and D).

[0163] The present invention is further illustrated by the following examples. EXAMPLES

[0164] Reference Example 1 Measurement of BET specific surface area and micropore surface area (ZSA) The BET specific surface area and the ZSA were determined according to DIN 66131 or DIN-ISO 9277 using liquid nitrogen.

[0165] Reference Example 2 Measurement of the average porosity and average pore size of porous wall-flow substrates The average porosity of the porous wall-flow substrates was determined by mercury intrusion using mercury porosimetry according to DIN 66133 and ISO 15901-1.

[0166] Reference Example 3 Determination of volumetric particle size distribution Particle size distribution was determined by static light scattering using Sympatec HELOS (3200) and QUIXEL instruments, and the optical density of the samples was in the range of 6–10%.

[0167] Reference Example 4 Preparation of Fe-CHA H-chabazite (Dv50 of 1.548 micrometers, SiO:15.7:1) 2 :Al 2 O 3 Molar ratio: 590m 2 / g BET specific surface area and 570 m 2 / g), the amount of iron is based on the weight of the chabazite, 2 O 3 Iron (iron source: Fe-(III)-nitrate-nonahydrate) was impregnated via incipient wetness impregnation to be 0.6 wt.% Fe calculated as 0.5 wt.% Fe.

[0168] Comparative Example 1 SCR catalyst not according to the present invention CuO powder having a Dv50 of 1.1 micrometers and a Dv90 of 5.8 micrometers was added to the water. The amount of CuO was calculated such that the total amount of copper, calculated as CuO, in the coating after firing was 5 wt.% based on the weight of the chabazite. Acetic acid and an aqueous zirconium acetate solution were added to the CuO-containing mixture to form a slurry. The amount of acetic acid was calculated to be 1.7 wt.% relative to the chabazite, and the amount of zirconium acetate was calculated to be 1.7 wt.% relative to the chabazite, and the amount of ZrO in the coating was calculated to be 1.7 wt.% based on the weight of the chabazite. 2 The amount of zirconia calculated as 0.5% by weight was calculated to be 5% by weight. H-chabazite (Dv50 of 1.548 micrometers, SiO2 content of 15.7:1) 2 :Al 2 O 3 , 590m 2 / g, and 570 m2 A micropore surface area (ZSA) of 1.5 g / g was added to the copper-containing slurry to form a mixture having a solids content of 41 wt. % based on the weight of the mixture. The resulting slurry was milled using a continuous milling device such that the particles had a Dv50 value of about 1.35 micrometers, the particles had a Dv90 value of about 2.5 micrometers, and the particles had a Dv90 value of about 7 micrometers.

[0169] Alumina powder (185m 2 % Al having a BET specific surface area of ​​about 1.0 μm / g, a Dv50 of 6.3 μm, and a Dv90 of about 16.3 μm. 2 O 3 and 20 wt.% SiO 2 ) was added to the Cu / CHA containing slurry. The amount of alumina+silica was calculated such that the amount of alumina+silica after calcination was 5 wt.% based on the weight of the calcined chabazite in the final catalyst. Water was added to the resulting mixture to obtain a mixture with a solids content of 42 wt.% based on the weight of the mixture.

[0170] A porous uncoated cordierite flow-through substrate (volume: 2 L, 400 cpsi, 3.5 mil wall thickness, diameter: 5.66 inches x length: 5 inches) was coated in a single coat with the final slurry from the inlet end to the outlet end over 100% of the substrate axial length. To do so, the substrate was immersed in the final slurry from the inlet end until the slurry reached the top of the substrate. The coated substrate was then dried at 140°C for 30 minutes and calcined at 450°C for 1 hour. The final coating loading in the catalyst after calcination was about 2.75 g / in3, which includes about 2.39 g / in3 of chabazite, 0.12 g / in3 of zirconia, 0.12 g / in3 of alumina, and 5 wt% Cu, based on the weight of the chabazite.

[0171] Example 1 SCR catalyst according to the present invention The catalyst of Example 1 was prepared using Fe-chabazite (Fe content: 0.6 wt. %, based on the weight of chabazite) prepared according to Reference Example 4.2 O 3 Calculated as: Dv50 of 1.548 microns, SiO:15.7:1 2 :Al 2 O 3 , 590m 2 / g, and 570 m 2 The catalyst was prepared similarly to that of Reference Example 1, except that H-chabazite was replaced with alumina powder (80 wt. % Al 2 O 3 and 20 wt.% SiO 2 , 185m 2 / g, Dv50 of 6.3 micrometers, and Dv90 of 16.3 micrometers. 2 O 3 and 50 wt% Al 2 O 3 , 112.85m 2 / g BET specific surface area, Dv50 of 9.6 micrometers, Dv90 of 20.5 micrometers, Dv99 of 28.2 micrometers. Based on the weight of the calcined chabazite, the amount of alumina + iron was calculated so that the amount of alumina + iron after calcination was 10 wt%.

[0172] The final coating loading in the catalyst after calcination was approximately 2.0 g / in3 of chabazite, 0.1 g / in3 of zirconia, 0.2 g / in3 of non-zeolitic oxide materials, based on the weight of chabazite, Fe. 2 O 3 The weight of the chabazite was 2.4 g / in3, containing 0.6 wt% Fe, calculated as CuO, and 5 wt% Cu, calculated as CuO, based on the weight of the chabazite. Other components were burned off and did not contribute to the final coating loading.

[0173] Example 2 Testing the performance of the catalysts prepared in Comparative Example 1 and Example 1 The catalysts of Comparative Example 1 and Example 1 were heated at 800° C. for 16 hours in N 2 10% of H 2 O and 20% O2 The mixture was hydrothermally aged in an oven using a 100% ethanol. Engine bench tests were performed under steady-state conditions to evaluate the DeNOx activity and N 2 The formation of O was measured, and the results are shown in Figures 1 and 2.

[0174] [Table 2]

[0175] As can be seen from Figure 1, the catalytic activity in terms of NOx conversion is similar for both catalysts, i.e., it shows good NOx conversion at low temperatures in the range of about 80-100%, as well as at high temperatures. However, as can be seen from Figure 2, while the results are similar at low temperatures (200 and 230°C), the SCR catalyst of the present invention shows a 50% increase in NOx conversion compared to the catalyst of Comparative Example 1, while maintaining a similar NOx conversion of about 90-98% at high temperatures, i.e., 601 and 650°C. 2 It is possible to reduce O formation.

[0176] Thus, the catalyst of the present invention, which includes iron combined with alumina in its coating, maintains very good NOx conversion at high temperatures while still providing a high NOx content. 2 This allows for a dramatic reduction in O formation.

[0177] Comparative Example 2 SCR on filter (SCRoF) catalyst not according to the present invention CuO powder having a Dv50 of 1.1 micrometers and a Dv90 of 5.8 micrometers was added to the water. The amount of CuO was calculated such that the total amount of copper in the coating after firing, calculated as CuO, was 4.15 wt% based on the weight of the chabazite. Sucrose was further added to the Cu mixture, and the amount of sucrose was calculated to be 4.15 wt% based on the weight of the chabazite. Acetic acid was added to the resulting slurry. The amount of acetic acid was calculated to be 1.7 wt% based on the weight of the chabazite. The resulting slurry had a solids content of 5 wt% based on the weight of the slurry. An aqueous solution of zirconium acetate was added to the CuO-containing mixture to form a slurry. The amount of zirconium acetate was calculated to be 1.7 wt% based on the weight of the chabazite. 2 The amount of zirconia calculated as zirconia per cubic meter (Dv50 of 1.548 micrometers, SiO ratio of 15.7:1) was calculated to be 20 wt.%, based on the weight of chabazite. 2 :Al 2 O 3 , 590m 2 / g BET specific surface area and 570 m 2 A copper-containing slurry having a solids content of 37% by weight based on the weight of the mixture was added with a micropore surface area (ZSA) of 1.0 g / g. The resulting slurry was milled using a continuous milling device such that the particles had a Dv99 value of about 9 micrometers, a Dv90 value of about 2.5 micrometers, and a Dv50 value of about 1.35 micrometers.

[0178] Alumina powder (178m 2 % Al having a BET specific surface area of ​​about 1.0 μm / g, a Dv50 of 2.6 μm, a Dv90 of 5.3 μm, and a Dv99 of about 8.5 μm. 2 O 3 ) was added to the Cu / CHA containing slurry. The amount of alumina was calculated such that the amount of alumina + silica after calcination was 10 wt% based on the weight of the calcined chabazite in the final catalyst. Water was added to the resulting mixture to obtain a mixture with a solids content of 37 wt% based on the weight of the mixture.

[0179] A porous uncoated wall-flow filter substrate, silicon carbide (volume: 3.4 L, average porosity of 59%, average pore size of 17.5 micrometers, and 350 cpsi and wall thickness of 12 mils, diameter: 6.43 inches by length: 6.39 inches), was coated twice with the mixture obtained from the optimized design, the first coat covering 70% of the substrate length from the outlet end to the inlet end, and the second coat also covering 70% of the substrate length from the inlet end to the outlet end, forming a single coating extending along the entire length of the substrate. To do so, the substrate was immersed in each slurry starting from the outlet end until the slurry reached 70% of the substrate length. After immersion from the outlet end, a pressure pulse was applied from the inlet end to blow off excess slurry. The substrate was further immersed in each slurry starting from the inlet end until the slurry reached 70% of the substrate length. After dipping from the inlet end, a pressure pulse was applied from the outlet end to blow off excess slurry. The coated substrate was then dried at 140° C. for 30 minutes and calcined at 450° C. for 1 hour. The final coating loading in the catalyst after calcination was 1.75 g / in3, containing approximately 1.31 g / in3 of chabazite, 0.26 g / in3 of zirconia, 0.13 g / in3 of alumina, and 4.15 wt. % Cu based on the weight of chabazite.

[0180] Example 3 SCR (SCRoF) catalyst on filter according to the present invention The catalyst of Example 3 was prepared using Fe-chabazite (Fe content: 0.6 wt. %, based on the weight of chabazite) prepared as described in Reference Example 4. 2 O 3 Calculated as: Dv50 of 1.548 microns, SiO:15.7:1 2 :Al 2 O 3 , 590m 2 / g, and 570 m 2 The catalyst was prepared similarly to that of Reference Example 2, except that H-chabazite was replaced with alumina powder (100 wt. % Al 2 O 3) was mixed with a powder of a non-zeolitic oxide material containing Fe and Al (50 wt. % Fe 2 O 3 and 50 wt.% Al 2 O 3 , a Dv50 of 10.15 micrometers, and a Dv90 of 100.13 micrometers.

[0181] The final coating loading in the catalyst after calcination was approximately 1.31 g / in3 of chabazite, 0.26 g / in3 of zirconia, and 0.13 g / in3 of non-zeolitic oxide materials, based on the weight of chabazite, Fe. 2 O 3 The weight percent of the FeO in the coating was 1.75 g / in3, containing 0.6 wt% Fe, calculated as CuO, and 4.15 wt% Cu, calculated as CuO, based on the weight of the chabazite. Other components were burned off and did not contribute to the final coating loading.

[0182] Comparative Example 3 SCR (SCRoF) catalyst on filter not according to the invention Outlet slurry: H-chabazite (Dv50 of 1.548 micrometers, SiO:15.7:1) 2 :Al 2 O 3 , 590m 2 / g BET specific surface area and 570 m 2 / g micropore surface area (ZSA)) was impregnated with Fe (based on the weight of chabazite, Fe 2 O 3(0.6 wt% Fe calculated as CuO, Fe source: Fe-(III)-nitrate-nonahydrate). Separately, CuO powder with Dv50 of 1.1 micrometers and Dv90 of 5.8 micrometers was added to the water. The amount of CuO was calculated such that the total amount of copper calculated as CuO in the coating after firing was 3.5 wt% based on the weight of the chabazite. Sucrose was further added to the Cu mixture, and the amount of sucrose was calculated to be 3.5 wt% based on the weight of the chabazite. Acetic acid was then added to the resulting slurry. The amount of acetic acid was calculated to be 1.7 wt% based on the weight of the chabazite. The resulting slurry had a solids content of 5 wt% based on the weight of the slurry. A zirconium acetate solution was added to the CuO-containing mixture to form a slurry. The amount of zirconium acetate was calculated to be 0.05 wt% ZrO in the coating. 2 The amount of zirconia, calculated as zirconia 20% by weight, was calculated based on the weight of chabazite. Further, the Fe-chabazite obtained above was added to water and mixed into the copper-containing slurry. The resulting slurry was milled using a continuous milling device such that the particles had a Dv99 value of about 9 micrometers, the particles had a Dv90 value of about 2.5 micrometers, and the particles had a Dv50 value of about 1.35 micrometers.

[0183] Alumina powder (178m 2 % Al having a BET specific surface area of ​​about 1.0 μm / g, a Dv50 of 2.6 μm, a Dv90 of 5.3 μm, and a Dv99 of about 8.5 μm. 2 O 3 ) was added to the chabazite-containing slurry. The amount of alumina was calculated such that the amount of alumina after calcination would be 10 wt. % based on the weight of the calcined chabazite. Water was added to the resulting mixture to obtain a mixture having a solids content of 37 wt. % based on the weight of the mixture.

[0184] Inlet slurry: Fe BEA zeolite (based on the weight of BEA, Fe 2 O 36.5 wt% Fe content calculated as, Dv50 of 2.1 micrometers, SiO ratio of 9.6:1 2 :Al 2 O 3 , 476m 2 ZrO2 in the coating (having a BET specific surface area of ​​100 nm / g) was dispersed with zirconium acetate. The amount of zirconium acetate was adjusted to 2 The amount of zirconia, calculated as zirconia per 1000 g of zirconia, was calculated to be 20 wt. % based on the weight of the BEA zeolite. The resulting mixture was milled using a continuous milling device such that the particles had a Dv99 value of about 9 micrometers, a Dv90 value of about 3 micrometers, and a Dv50 value of about 1.5 micrometers. Additionally, alumina powder (178 m 2 % Al having a BET specific surface area of ​​about 1.0 μm / g, a Dv50 of 2.6 μm, a Dv90 of 5.3 μm, and a Dv99 of about 8.5 μm. 2 O 3 ) was added to the BEA-containing slurry. The amount of alumina was calculated such that the amount of alumina after calcination was 10 wt. % based on the weight of the calcined BEA. Water was added to the resulting mixture to obtain a mixture with a solids content of 37 wt. % based on the weight of the mixture.

[0185] A porous uncoated wall-flow filter substrate, silicon carbide (volume: 3.4 L, average porosity of 59%, average pore size of 17.5 micrometers, and 350 cpsi and wall thickness of 12 mils, diameter: 6.43 inches by length: 6.39 inches), was coated twice with the optimized design, the first coating with the outlet slurry was applied over 80% of the substrate length from the outlet end to the inlet end, followed by a second coating with the inlet slurry similarly over 80% of the substrate length from the inlet end to the outlet end. To do so, the substrate was immersed in the respective slurries starting from the outlet end until the slurries reached 80% of the substrate length. After immersion from the outlet end, a pressure pulse was applied from the inlet end to blow off excess slurry. Further, the substrate was immersed in the respective slurries starting from the inlet end until the slurries reached 80% of the substrate length. After immersion from the inlet end, a pressure pulse was applied from the outlet end to blow off excess slurry. The coated substrate was then dried at 140° C. for 30 minutes and calcined at 450° C. for 1 hour.

[0186] The final coating loading in the catalyst after calcination was 1.76 g / in3, including approximately 1.6 g / in3 of the chabazite-based coat and 0.6 g / in3 of the Fe-BEA-based coat.

[0187] Example 4 Testing the performance of the catalysts prepared in Comparative Examples 2 and 3 and Example 3 The catalysts of Comparative Examples 2 and 3 and Example 3 were subjected to high flow rate 25 L, 2.422 ml / min H for 16 hours before testing. 2 O and 20% O 2 (The rest is N 2 ) and hydrothermally aged in an oven at 850 °C. Engine bench tests were performed under steady-state conditions (Daimler-OM651, 2.2 L, 4 Zyl, 150 kW), and the DeNOx activity and N 2 The formation of O was measured, and the results are shown in Figures 3 to 6.

[0188] [Table 3]

[0189] As can be seen from Figure 3, the catalyst according to the present invention shows good NOx conversion at low and high temperatures, i.e., about 95% at 231°C, 90% at 599°C, and about 75% at 650°C, which are very similar to the NOx conversion obtained with the catalyst of Comparative Example 2. However, as can be seen from Figure 4, the SCR catalyst of the present invention shows a significantly lower NOx conversion than the catalyst of Comparative Example 2 over a very wide temperature range from 195°C to 650°C. 2 It is possible to reduce the formation of O by about 50%. Furthermore, compared with the catalyst of Comparative Example 3, the catalyst of Example 2 according to the present invention has good NOx conversion and acceptable N 2 In fact, the catalyst of Example 2 shows about 20-30% improved NOx conversion compared to the catalyst of Comparative Example 3, and the N 2 O formation increases by only 0.5% at low temperature compared to the catalyst of Comparative Example 3. This is illustrated by Figures 5 and 6.

[0190] Thus, the catalyst of the present invention, which includes iron combined with alumina in its coating, maintains very good NOx conversion at high temperatures while still providing a high NOx content. 2 This allows for a dramatic reduction in O formation.

[0191] Comparative Example 4 SCR (SCRoF) catalyst on filter not according to the invention The catalyst of Comparative Example 4 was prepared similarly to the catalyst of Comparative Example 2, except that Fe-CHA was substituted for H-CHA, the CHA having a Dv50 of 1.548 micrometers, SiO of 15.7:1. 2 :Al 2 O 3 , 590m 2 / g, and 570 m 2 / g based on the weight of the chabazite. 2 O 3The Fe content, calculated as Fe / in, was 0.6 wt. % and the Fe-CHA was prepared according to Reference Example 4 herein. The final coating loading in the catalyst after calcination was about 1.31 g / in3 of chabazite, 0.26 g / in3 of zirconia, 0.13 g / in3 of alumina, and 0.01 g / in3 of Fe, based on the weight of chabazite. 2 O 3 % Cu, calculated as CuO, based on the weight of the chabazite.

[0192] Reference Example 5: Comparison of the performance of Comparative Examples 2 and 4 The catalysts of Comparative Examples 2 and 4 were subjected to high flow 25 L flow, 20% O for 16 hours prior to testing. 2 , 2.422 ml / min H 2 O (the rest is N 2 ) and hydrothermally aged in an oven at 850 °C. Engine bench tests were performed under steady-state conditions (Daimler-OM651, 2.2 L, 4 Zyl, 150 kW), and the DeNOx activity and N 2 The formation of O was measured, and the results are shown in Figures 7 and 8.

[0193] [Table 4]

[0194] As can be seen from FIG. 7, the NOx conversion performances of the two comparative examples are almost the same. Moreover, as can be seen from FIG. 8, the nitrous oxide formation is reduced by more than 0.5% with the catalyst of Comparative Example 4 using Cu / Fe-CHA (starting zeolite is Fe-impregnated CHA) compared to the catalyst of Comparative Example 2 using Cu-CHA (starting zeolite is H-CHA). It can therefore be deduced from the example that the use of Fe / Cu-CHA in the catalyst makes it possible to reduce the nitrous oxide formation compared to the use of Cu-CHA in such a catalyst. However, the nitrous oxide formation obtained with the catalyst of Comparative Example 4 is higher than that obtained with the catalyst of Example 1 according to the invention. In fact, with the catalyst of the invention, a clear reduction of nitrous oxide can be seen at low as well as high temperatures, with nitrous oxide being reduced by about 2% at 650° C. compared to Comparative Example 2.

[0195] Thus, from the experimental section of the present invention, it can be seen that the catalyst according to the present invention, which comprises iron combined with alumina in its coating, is able to reduce N while maintaining very good NOx conversion. 2 It has been clearly demonstrated that this allows for a dramatic reduction in O formation.

[0196] Example 5 SCR (SCRoF) catalyst on filter according to the present invention The catalyst of Example 5 was - H-chabazite with a Dv50 of 1 micrometer and SiO of 18:1 2 :Al 2 O 3 , 550m 2 / g, and 520 m 2 H-chabazite having a micropore surface area ZSA of / g; - Alumina powder (80% by weight Al 2 O 3 and 20 wt.% SiO 2 , 185m 2 / g, Dv50 of 6.3 micrometers, and Dv90 of 16.3 micrometers) was obtained by subjecting a powder of a non-zeolitic oxide material containing Fe and Al (50 wt. % Fe2 O 3 and 50 wt.% Al 2 O 3 , 112.85m 2 / g BET specific surface area, Dv50 of 9.6 micrometers, Dv90 of 20.5 micrometers, and Dv99 of 28.2 micrometers; - Prepared similarly to the catalyst of Comparative Example 2, except that the porous uncoated wall-flow filter substrate, silicon carbide, having a volume of 3.4 L, an average porosity of 59%, an average pore size of 17.5 micrometers, and 350 cpsi, and a wall thickness of 12 mils, a diameter of 6.43 inches by length of 6.39 inches, was replaced with a porous uncoated wall-flow filter substrate, silicon carbide, having a volume of 0.428 L, an average porosity of 59%, an average pore size of 17.5 micrometers, and 350 cpsi, and a wall thickness of 12 mils, a diameter of 2.3 inches by length of 6.39 inches.

[0197] The final coating loading in the catalyst after calcination was 1.97 g / in3, containing about 1.469 g / in3 of chabazite, 0.29 g / in3 of zirconia, 0.15 g / in3 of non-zeolitic oxide materials including Fe and Al, and 4.15 wt. % Cu, calculated as CuO, based on the weight of chabazite. Other components were burned off and did not contribute to the final coating loading.

[0198] Comparative Example 5 SCR (SCRoF) catalyst on filter not according to the invention The catalyst of Comparative Example 5 was prepared by mixing H-chabazite with a Dv50 of 1 micrometer and SiO of 18:1. 2 :Al 2 O 3 , 550m 2 / g, and 520 m 2The catalyst was prepared similarly to Comparative Example 2, except that H-chabazite having a micropore surface area ZSA of 100 / g was substituted with H-chabazite having a micropore surface area ZSA of 100 / g, and that a porous uncoated wall-flow filter substrate, silicon carbide having a volume of 3.4 L, an average porosity of 59%, an average pore size of 17.5 micrometers, and 350 cpsi, and a wall thickness of 12 mils, diameter: 6.43 inches x length: 6.39 inches was substituted with a porous uncoated wall-flow filter substrate, silicon carbide having a volume of 0.428 L, an average porosity of 59%, an average pore size of 17.5 micrometers, and 350 cpsi, and a wall thickness of 12 mils, diameter: 2.3 inches x length: 6.39 inches.

[0199] The final coating loading in the catalyst after calcination was 1.97 g / in3, containing about 1.469 g / in3 of chabazite, 0.29 g / in3 of zirconia, 0.15 g / in3 of non-zeolitic oxide materials including Fe and Al, and 4.15 wt. % Cu, calculated as CuO, based on the weight of chabazite. Other components were burned off and did not contribute to the final coating loading.

[0200] Example 6 Testing the performance of the catalysts prepared in Comparative Example 5 and Example 5 The catalysts of Comparative Example 5 and Example 5 were incubated in 10% H for 16 hours before testing. 2 O and 20% O 2 (The rest is N 2 ) and hydrothermally aged in an oven at 850 °C. Engine bench tests were performed under steady-state conditions (Daimler-OM651, 2.2 L, 4 Zyl, 150 kW). DeNOx activity and N 2 The formation of O was measured, and the results are shown in Figures 9 to 10.

[0201] [Table 5]

[0202] As can be seen from Figure 9, the catalyst according to the invention (Example 5) shows good NOx conversion at high temperatures, i.e., about 95% at 578°C and about 80% at 630°C, which are very similar to the NOx conversion obtained with the catalyst of Comparative Example 5. However, as can be seen from Figure 10, the SCR catalyst of the invention shows a NOx conversion of more than 7% at 578°C and up to 16% at 630°C compared to the catalyst of Comparative Example 5. 2 Furthermore, compared to the catalyst of Comparative Example 5, the catalyst of Example 5 according to the present invention exhibits good NOx conversion and acceptable N 2 This represents the best compromise in terms of the balance between O formation.

[0203] Thus, the catalyst of the present invention, which includes iron combined with alumina in its coating, maintains very good NOx conversion at high temperatures while still providing a high NOx content. 2 This allows for a dramatic reduction in O formation. [Brief description of the drawings]

[0204] [Figure 1] 1 shows the NOx conversion obtained with the catalysts of Example 1 and Comparative Example 1 at different temperatures. [Diagram 2] Figure 2 shows the N2O formed when using the catalysts of Example 1 and Comparative Example 1 at different temperatures. Relative N2O is calculated according to the formula: Relative N2O [%] = N2O [ppm] / (NOx engine out [ppm] * NOx conversion [%] / 100) * 100. [Diagram 3] 4 shows the NOx conversion obtained with the catalysts of Example 3 and Comparative Example 2 over a wide temperature range (195-650° C.). [Figure 4] Figure 1 shows the N2O formed when using the catalysts of Example 3 and Comparative Example 2 over a wide temperature range (195-650°C). Relative N2O is calculated according to the formula Relative N2O [%] = N2O [ppm] / (NOx engine out [ppm] * NOx conversion [%] / 100) * 100. [Diagram 5] 4 shows the NOx conversion obtained with the catalysts of Example 3 and Comparative Examples 2 and 3 at low temperatures (198 and 231° C.). [Figure 6]Shows the N2O formed when using the catalysts of Example 3 and Comparative Examples 2 and 3 at low temperatures (198 and 231°C). Relative N2O is calculated according to the formula: Relative N2O [%] = N2O [ppm] / (NOx engine out [ppm] * NOx conversion [%] / 100) * 100. [Figure 7] 4 shows the NOx conversion obtained with the catalysts of Comparative Examples 2 and 4. [Figure 8] Figure 2 shows the N2O formed when using the catalysts of Comparative Examples 2 and 4. Relative N2O is calculated according to the formula: Relative N2O [%] = N2O [ppm] / (NOx engine out [ppm] * NOx conversion [%] / 100) * 100. [Figure 9] 4 shows the NOx conversion obtained with the catalysts of Comparative Example 5 and Example 5. [Figure 10] 4 shows the relative N2O advantage formed when using the catalyst of Example 5 versus the catalyst of Comparative Example 5.

[0205] References - US Patent No. 9242238 (B2) - US Patent No. 9352307 (B2) - US Patent No. 9999877 (B2)

Claims

1. A catalyst for the selective catalytic reduction of NOx, A substrate having a plurality of passages defined by an inlet end, an outlet end, an axial length of the substrate extending from the inlet end to the outlet end, and the inner wall of the substrate extending through therethe, A coating comprising a zeolite material, copper, and a first non-zeolite oxide material comprising iron and aluminum, wherein at least 25% by weight of the first non-zeolite oxide material is Fe ２ O ３ A catalyst comprising a coating and iron calculated as such.

2. The catalyst according to claim 1, wherein the zeolite material contained in the coating is selected from the group consisting of CHA, AEI, RTH, LEV, DDR, KFI, ERI, AFX, mixtures of two or more of these, and mixed forms of two or more of these, more preferably selected from the group consisting of CHA, AEI, RTH, AFX, mixtures of two or more of these, and mixed forms of two or more of these, and more preferably selected from the group consisting of CHA and AEI, and the zeolite material contained in the coating more preferably has a skeletal CHA.

3. The catalyst according to claim 1 or 2, wherein the amount of copper included in the coating, calculated as CuO, is in the range of 2 to 10% by weight, preferably 2.5 to 8% by weight, more preferably 3 to 7% by weight, and more preferably 3.5 to 6% by weight, based on the weight of the zeolite material, and the zeolite material included in the coating preferably contains copper.

4. The zeolite material contains iron, and the zeolite material contains Fe ２ O ３ The catalyst according to claim 1 or 2, wherein the amount of iron calculated as is in the range of 0.1 to 1.5% by weight, preferably 0.15 to 1.25% by weight, more preferably 0.25 to 1% by weight, and more preferably 0.3 to 0.8% by weight, based on the weight of the zeolite material.

5. 25 to 65% by weight, preferably 30 to 60% by weight, more preferably 40 to 55% by weight, and more preferably 45 to 55% by weight of the first non-zeolite oxide material is Fe ２ O ３ The catalyst according to claim 1 or 2, comprising iron calculated as such.

6. The catalyst according to claim 1 or 2, wherein the coating comprises the first non-zeolite oxide material in an amount ranging from 5 to 20% by weight, preferably 7 to 15% by weight, and more preferably 8 to 12% by weight, based on the weight of the zeolite material.

7. The catalyst according to claim 1 or 2, wherein 99 to 100% by weight, preferably 99.5 to 100% by weight, and more preferably 99.9 to 100% by weight of the first non-zeolite oxide material consists of Al, Fe, and O.

8. The catalyst according to claim 1 or 2, wherein the weight ratio of the zeolite material to the first non-zeolite oxide material is in the range of 4.6:1 to 10:1, more preferably in the range of 6:1 to 9.3:1, and more preferably in the range of 7:1 to 8.75:

1.

9. The coating further comprises a second non-zeolite oxide material, the second non-zeolite oxide material preferably comprises one or more of zirconia, alumina, titania, silica, and mixed oxides comprising two or more of Zr, Al, Ti, and Si, more preferably comprises one or more of silica, alumina, and zirconia, more preferably comprises one or more of alumina and zirconia, more preferably comprises zirconia. Preferably 95 to 100% by weight, more preferably 98 to 100% by weight, more preferably 99 to 100% by weight, and more preferably 99.5 to 100% by weight of the second non-zeolite oxide material contained in the coating is ZrO ２ The catalyst according to claim 1 or 2, comprising zirconium calculated as such.

10. A process for preparing a catalyst for the selective catalytic reduction of NOx, preferably the catalyst described in claim 1, (i) Prepare a first aqueous mixture comprising water, a copper source, and preferably a precursor of a second non-zeolite oxide component. (ii) Mixing the first aqueous mixture obtained according to (i) with water and a zeolite material, wherein the zeolite material does not contain copper and optionally contains iron, to obtain a second aqueous mixture. (iii) Mixing a first non-zeolite oxide material containing Al and Fe with the second aqueous mixture prepared according to (ii), wherein at least 25% by weight of the first non-zeolite oxide material consists of iron calculated as ２ O ３ and preferably adding water to obtain a third aqueous mixture, the mixing The third aqueous mixture obtained according to (iv)(iii) is placed on a substrate having a plurality of passages defined by an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and the inner wall of the substrate extending through therethrough, and the substrate containing the mixture is optionally dried. A process comprising (v) firing the substrate obtained in (iv).

11. (i) is, (i.1) To prepare a mixture comprising water and the copper source, wherein the mixture preferably further comprises an acid, more preferably an organic acid, and more preferably acetic acid. (i.2) The process according to claim 10, comprising adding the precursor of the second non-zeolite oxide component to the mixture obtained according to (i.1) to obtain the first aqueous mixture.

12. 90 to 100% by weight, preferably 93 to 99% by weight, more preferably 96 to 99% by weight of the copper source, are present in an insoluble state in the mixture prepared in (i.1). The process according to claim 11, wherein the copper particles in the mixture according to (i.1) preferably have a Dv90 in the range of 0.1 to 15 micrometers, more preferably in the range of 0.5 to 10 micrometers, more preferably in the range of 1 to 8 micrometers, and more preferably in the range of 3 to 7 micrometers.

13. A catalyst for the selective catalytic reduction of NOx, which can be obtained or obtained by the process described in claim 10.

14. An exhaust gas treatment system for treating exhaust gases from a compression ignition engine, preferably a diesel engine, wherein the exhaust gas treatment system has an upstream end for introducing the exhaust gas flow into the exhaust gas treatment system, and the exhaust gas treatment system comprises a catalyst according to any one of claims 1 to 2 and 13, and one or more of a diesel oxidation catalyst, a selective catalytic reduction catalyst, an ammonia oxidation catalyst, a NOx trap, and a particulate filter.

15. The system according to claim 14, comprising a diesel oxidation catalyst, wherein the catalyst according to claim 1 is located downstream of the diesel oxidation catalyst.

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