Composition for SCR catalysts

Patent metadata

Field	Value
Publication number	US-12458958-B2
Application number	US-202117996978-A
Country	US
Kind code	B2
Filing date	Apr 27, 2021
Priority date	Apr 28, 2020
Publication date	Nov 4, 2025
Grant date	Nov 4, 2025

Abstract

The present invention relates to a composition comprising a non-zeolitic oxidic material comprising alumina; an 8-membered ring pore zeolitic material comprising one or more of copper and iron, wherein the framework structure of the zeolitic material comprises a tetravalent element Y, a trivalent element X and oxygen, wherein the molar ratio of Y:X, calculated as YO 2 X 2 O 3 , is in the range of from 2:1 to 40:1; wherein at least part of the outer surface of the zeolitic material is covered by a layer comprising the non-zeolitic oxidic material; wherein Y comprises one or more of Si, Sn, Ti, Zr and Ge and X comprises one or more of Al, B, In and Ga.

First claim

The invention claimed is:

1 . A composition comprising:
(i) a non-zeolitic oxidic material comprising alumina; and (ii) an 8-membered ring pore zeolitic material comprising one or more of copper and iron, wherein a framework structure of the zeolitic material comprises a tetravalent element Y, a trivalent element X and oxygen, wherein the molar ratio of Y:X, calculated as YO 2 :X 2 O 3 , ranges from 2:1 to 40:1; wherein at least part of the outer surface of the zeolitic material according to (ii) is covered by a layer comprising the non-zeolitic oxidic material according to (i); and wherein Y comprises one or more of Si, Sn, Ti, Zr and Ge and X comprises one or more of Al, B, In and Ga; wherein the composition is obtainable or obtained by a process, the process comprising: (a) providing an 8-membered ring pore zeolitic material, comprising one or more of copper and iron, wherein the framework structure of the zeolitic material comprises a tetravalent element Y, a trivalent element X and oxygen, wherein the molar ratio of Y:X, calculated as YO2:X2O3, is in the range of from 2:1 to 40:1; (b) providing a source of a non-zeolitic oxidic material comprising alumina, wherein the source of the non-zeolitic oxidic material is a colloid dispersion comprising particles of the non-zeolitic oxidic material, wherein the particles of the non-zeolitic oxidic material have a Dv50 in the range of from 30 to 200 nm; (c) admixing the zeolitic material obtained in (a) with the source of the non-zeolitic oxidic material comprising alumina obtained in (b), forming a mixture; (d) calcining the mixture obtained in (c) in a gas atmosphere having a temperature in the range of from 400 to 800° C.

2 . The composition of claim 1 , wherein from 98 weight-% to 100 weight of the non-zeolitic oxidic material according to (i) consist of alumina.

3 . The composition of claim 1 , wherein the layer comprising the non-zeolitic oxidic material according to (i) has an average thickness ranging from 2 nm to 100 nm.

4 . The composition of claim 1 , wherein from 99 weight-% to 100 weight-%, of the layer consist of the non-zeolitic oxidic material according to (i).

5 . The composition of claim 1 , wherein the 8-membered ring pore zeolitic material according to (ii) has a framework type selected from the group consisting of CHA, AEI, RTH, LEV, DDR, KFI, ERI, AFX, LTA, a mixture of two or more thereof and a mixed type of two or more thereof, preferably selected from the group consisting of CHA, AEI, RTH, a mixture of two or more thereof and a mixed type of two or more thereof, more preferably selected from the group consisting of CHA and AEI.

6 . The composition of claim 1 , wherein from 20% to 100%, of the outer surface of the zeolitic material according to (ii) are covered by the layer comprising the non-zeolitic oxidic material according to (i).

7 . A slurry comprising a composition according to claim 1 and a dispersion agent, wherein the dispersion agent is one or more of water, ethanol, acetic acid, nitric acid, lactic acid, and a mixture of two or more thereof.

8 . A selective catalytic reduction catalyst for treating an exhaust gas of a combustion engine, the catalyst comprising:
(1) a substrate comprising 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 internal walls of the substrate extending therethrough; (2) a coating disposed on the substrate (i), the coating comprising a composition according to claim 1 .

9 . The catalyst of claim 8 , wherein the coating ( 2 ) further comprises an oxidic binder, wherein the oxidic binder comprises one or more of zirconia, alumina, titania, silica, and a mixed oxide comprising two or more of Zr, Al, Ti, and Si.

10 . The catalyst of claim 8 , wherein the coating ( 2 ) comprises the composition in an amount ranging from 80 weight-% to 100 weight-%, based on the weight of the coating ( 2 ).

11 . The catalyst of claim 8 , wherein the substrate is a wall-flow filter substrate, wherein the plurality of passages comprises inlet passages having an open inlet end and a closed outlet end, and outlet passages having a closed inlet end and an open outlet end.

12 . A process for preparing the selective catalytic reduction catalyst for treating an exhaust gas of a combustion engine, the process comprising
(A) preparing a mixture comprising water and a composition according to claim 1 ; (B) disposing the mixture obtained according to (A) on a substrate, the substrate comprising 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 internal walls of the substrate extending therethrough, obtaining a mixture-treated substrate; (C) calcining the mixture-treated substrate obtained according to (B), obtaining the substrate having a coating disposed thereon.

13 . A process for preparing a composition, the process comprising:
(a) providing an 8-membered ring pore zeolitic material, comprising one or more of copper and iron, wherein a framework structure of the zeolitic material comprises a tetravalent element Y, a trivalent element X and oxygen, wherein the molar ratio of Y:X, calculated as YO 2 :X 2 O 3 , ranges from 2:1 to 24:1, wherein the zeolitic material comprises crystals having an average crystal size in the range of from 0.05 micrometers to 5 micrometers; (b) providing a source of a non-zeolitic oxidic material comprising alumina, wherein the source of the non-zeolitic oxidic material is a colloid dispersion comprising particles of the non-zeolitic oxidic material, wherein the particles of the non-zeolitic oxidic material have a Dv50 ranging from 30 nm to 200 nm; (c) admixing the zeolitic material obtained in (a) with the source of the non-zeolitic oxidic material comprising alumina obtained in (b), forming a mixture; and (d) calcining the mixture obtained in (c) in a gas atmosphere having a temperature ranging from 400° C. to 800° C.

14 . The process of claim 13 , wherein the crystals of the 8-membered ring pore zeolitic material have an average crystal size ranging from 0.06 micrometers to 2 micrometers.

15 . The process of claim 13 , wherein the 8-membered ring pore zeolitic material comprises particles having a Dv50 ranging from 0.5 micrometers to 4 micrometers.

16 . The process of claim 13 , wherein the colloid dispersion comprising particles of the non-zeolitic oxidic material provided in (b) is alumina sol.

17 . The process of claim 13 , wherein the particles of the non-zeolitic oxidic material, the particles of alumina, have a Dv50 ranging from 50 nm to 150 nm.

Assignees

• Basf Mobile Emissions Catalysts Llc
• Heesung Catalysts Corp

Inventors

• Peter Matthias
• Zabel Claudia
• Heenemann Maria
• Xue Wen-Mei
• Kim Eunseok
• Rao Narayana K
• Pollick David

Classifications

• B01J35/77

  Compounds characterised by their crystallite size · CPC title

• B01J2235/10

  Infrared [IR] · CPC title

• B01J2235/30

  Scanning electron microscopy; Transmission electron microscopy · CPC title

• B01J35/30

  characterised by their physical properties · CPC title

• F01N3/2073

  Means for generating a reducing substance from the exhaust gases · CPC title