Use of a palladium/platinum/zeolite-based catalyst as passive nitrogen oxide adsorber for purifying exhaust gas

Patent metadata

Field	Value
Publication number	US-2020246784-A1
Application number	US-201816641876-A
Country	US
Kind code	A1
Filing date	Aug 24, 2018
Priority date	Aug 31, 2017
Publication date	Aug 6, 2020
Grant date	—

Abstract

The invention relates to the use of a catalyst as a passive nitrogen oxide adsorber, which has a carrier substrate, a zeolite, palladium, and platinum, wherein the palladium is provided in a quantity of 0.01 to 10 wt. %, based on the sum of the weights of zeolite, platinum, and palladium and calculated as a palladium metal, and platinum in a quantity of 0.1 to 10 wt. %, based on the weight of the palladium and calculated as a platinum metal. The invention also relates to the use of said catalyst in connection with a SCR catalyst in an exhaust gas system.

First claim

1 . Use of a catalyst comprising a carrier substrate of length L and a coating A comprising a zeolite, palladium and platinum, wherein palladium is present in amounts of 0.01 to 10 wt. %, based on the sum of the weights of zeolite, platinum and palladium, and is calculated as palladium metal, and platinum is present in amounts of 0.1 to 10 wt. %, based on the weight of palladium, and is calculated as platinum metal, as a passive nitrogen oxide adsorber that stores nitrogen oxides in a first temperature range and releases them again in a second temperature range, wherein the second temperature range is at higher temperatures than the first temperature range.

2 . Use according to claim 1 , characterized in that the largest channels of the zeolite are formed by 6 tetrahedrally coordinated atoms and the zeolite belongs to structure types AFG, AST, DOH, FAR, FRA, GIU, LIO, LOS, MAR, MEP, MSO, MTN, NON, RUT, SGT, SOD, SVV, TOL or UOZ.

3 . Use according to claim 1 , characterized in that the largest channels of the zeolite are formed by 8 tetrahedrally coordinated atoms and the zeolite belongs to structure types ABW, ACO, AEI, AEN, AFN, AFT, AFV, AFX, ANA, APC, APD, ATN, ATT, ATV, AVL, AWO, AWW, BCT, BIK, BRE, CAS, CDO, CHA, DDR, DFT, EAB, EDI, EEI, EPI, ERI, ESV, ETL, GIS, GOO, IFY, IHW, IRN, ITE, ITW, JBW, JNT, JOZ, JSN, JSW, KFI, LEV, -LIT, LTA, LTJ, LTN, MER, MON, MTF, MWF, NPT, NSI, OWE, PAU, PHI, RHO, RTH, RWR, SAS, SAT, SAV, SBN, SIV, THO, TSC, UEI, UFI, VNI, YUG or ZON.

4 . Use according to claim 1 , characterized in that the largest channels of the zeolite are formed by 9 tetrahedrally coordinated atoms and the zeolite belongs to structure types -CHI, LOV, NAB, NAT, RSN, STT or VSV.

5 . Use according to claim 1 , characterized in that the largest channels of the zeolite are formed by 10 tetrahedrally coordinated atoms and the zeolite belongs to structure types FER, MEL, MFI, MTT, MWW or SZR.

6 . Use according to claim 1 , characterized in that the largest channels of the zeolite are formed by 12 tetrahedrally coordinated atoms and the zeolite belongs to structure types AFI, AFR, AFS, AFY, ASV, ATO, ATS, BEA, BEC, BOG, BPH, CAN, CON, CZP, DFO, EMT, EON, EZT, FAU, GME, GON, IFR, ISV, IWR, IWV, IWW, LTL, MAZ, MEI, MOR, MOZ, MSE, MTW, NPO, OFF, OSI, -RON, RWY, SAO, SBE, SBS, SBT, SFE, SFO, SOS, SSY, USI or VET.

7 . Use according to claim 1 , characterized in that the zeolite belongs to structure types ABW, AEI, AFX, BEA, CHA, ERI, ESV, FAU, FER, KFI, LEV, LTA, MFI, SOD or STT.

8 . Use according to claim 1 , characterized in that the palladium and the platinum are present as a cation in the zeolite structure.

9 . Use according to claim 1 , characterized in that it comprises a zeolite of structure type ABW, AEI, AFX, BEA, CHA, ERI, ESV, FAU, FER, KFI, LEV, LTA, MFI, SOD or STT with 0.5 to 3 wt. % of palladium, based on the sum of the weights of zeolite, platinum and palladium, and calculated as palladium metal, and 0.5 to 5 wt. % of platinum, based on the weight of palladium, and calculated as platinum metal.

10 . Use according to claim 1 , characterized in that the carrier substrate carries another catalytically active coating B, which Is a coating that is active in terms of catalytic oxidation and comprises platinum, palladium or platinum and palladium on a carrier material.

11 . Use according to claim 1 , characterized in that a zeolite of structure type ABW, AEI, AFX, BEA, CHA, ERI, ESV, FAU, FER, KFI, LEV, LTA, MFI, SOD or STT coated with 0.5 to 3 wt. % of palladium, based on the sum of the weights of zeolite, platinum and palladium, and calculated as palladium metal, and 0.5 to 5 wt. % of platinum, based on the weight of the palladium, and calculated as platinum metal, extends directly on the carrier substrate over its entire length L, and on this coating there is a coating containing platinum or platinum and palladium in a mass ratio of 2:1 to 14:1 over the entire length L.

12 . Use according to claim 1 , characterized in that the catalyst is a component of an exhaust gas system comprising an SCR catalyst.

13 . Use according to claim 12 , characterized in that the SCR catalyst is a zeolite belonging to the scaffold type BEA, AEI, CHA, KFI, ERI, LEV, MER or DDR and is exchanged with copper, iron or copper and iron.

Assignees

• Umicore Ag & Co Kg

Inventors

• Hengst Christoph
• Lennartz Michael
• Schuetze Frank-Walter

Classifications

• B01J35/56

  Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional [3D] monoliths · CPC title

• B01J29/7492 Primary

  MTT-type, e.g. ZSM-23, KZ-1, ISI-4 or EU-13 · CPC title

• B01D53/9468

  in different layers · CPC title

• B01D53/944

  Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts (three-way-catalysts [TWC] B01D53/9445) · CPC title

• B01D2255/1021

  Platinum · CPC title