# US 10,369,555 B2 · Catalytic wall-flow filter with an ammonia slip catalyst

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- Number: US 10,369,555 B2
- Document ID: US10369555B2
- Status: Granted
- Kind: B2
- Application number: 15/925,806
- Filed: 2018-03-20
- Published: 2018-09-20
- Granted: 2019-08-06
- Earliest claimed: 2017-03-20
- Assignees: Johnson Matthey Public Limited Company
- Applicants: Johnson Matthey Public Limited Company
- Inventors: Garry Adam Burgess; Guy Richard Chandler; Keith Anthony Flanagan; David Marvell; Paul Richard Phillips
- Web page: https://patentgrep.com/patent/US10369555B2

## CPC

- B01J 29/763: {CHA-type, e.g. Chabazite, LZ-218}
- B01D 53/9418: {for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas}
- B01D 53/9436: {Ammonia}
- B01D 53/9468: {in different layers}
- B01D 53/9472: {in different zones}
- B01J 23/42: Platinum
- B01J 23/888: Tungsten
- B01J 35/19: {Catalysts containing parts with different compositions}
- B01J 35/56: Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional [3D] monoliths
- B01J 37/024: {Multiple impregnation or coating}
- F01N 3/0222: {the structure being monolithic, e.g. honeycombs}
- F01N 3/035: with catalytic reactors
- F01N 3/2066: {Selective catalytic reduction [SCR]}
- F01N 3/28: Construction of catalytic reactors
- F01N 13/0093: {the purifying devices are of the same type}
- B01D 2255/1021: Platinum
- B01D 2255/20746: Cobalt
- B01D 2255/2092: Aluminium
- B01D 2255/50: Zeolites
- B01D 2255/502: Beta zeolites
- B01D 2255/9022: Two layers
- B01D 2255/9032: Two zones
- B01D 2255/9035: Three zones
- B01D 2255/9155: Wall flow filters
- F01N 2330/06: Ceramic, e.g. monoliths
- F01N 2370/04: Zeolitic material
- F01N 2610/02: the substance being ammonia or urea
- Y02C 20/10: of nitrous oxide (N2O)
- Y02T 10/12: Improving ICE efficiencies
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A catalytic wall-flow monolith filter for use in an emission treatment system comprises a wall flow monolith comprising a porous substrate having surfaces that define the channels and having a first zone extending in the longitudinal direction from a first end face towards a second end face for a distance less than the filter length and a second zone extending in the longitudinal direction from the second end face towards the first end face and extending in the longitudinal direction for a distance less than the filter length, wherein a first SCR catalyst is distributed throughout the first zone of the porous substrate, an ammonia oxidation catalyst is distributed throughout the second zone of the porous substrate and a second SCR catalyst is located in a layer that covers the surfaces in the second zone of the porous substrate.

## Claims

### Claim 1

A catalytic wall-flow monolith filter for use in an emission treatment system comprises a first end face, a second end face, a filter length defined by the distance from the first end face to the second end face, a longitudinal direction between the first end face and the second end face, and first and second pluralities of channels extending in the longitudinal direction,
wherein the first plurality of channels is open at the first end face and closed at the second end face, and the second plurality of channels is open at the second end face and closed at the first end face,
wherein the monolith filter comprises a porous substrate having surfaces that define the channels and having a first zone extending in the longitudinal direction from the first end face towards the second end face for a distance less than the filter length and a second zone extending in the longitudinal direction from the second end face towards the first end face and extending in the longitudinal direction for a distance less than the filter length,
wherein the first zone comprises a first SCR catalyst distributed throughout the porous substrate, and the second zone comprises an ammonia oxidation catalyst distributed throughout the porous substrate and a second SCR catalyst located in a layer that covers the surfaces in the second zone of the porous substrate.

### Claim 2 (depends on 1)

The catalytic wall-flow monolith filter according to claim 1, wherein the second SCR catalyst is present only in the layer that covers the surfaces of the porous substrate in the second zone.

### Claim 3 (depends on 1)

The catalytic wall-flow monolith filter according to claim 1, wherein the second SCR catalyst is present in the layer that covers the surfaces of the porous substrate in the second zone and in all or a portion of the porous substrate in the second zone.

### Claim 4 (depends on 3)

The catalytic wall-flow monolith filter according to claim 3, wherein the second SCR catalyst is present in the layer that covers the surfaces of the porous substrate in the second zone and in all of the porous substrate in the second zone.

### Claim 5 (depends on 3)

The catalytic wall-flow monolith filter according to claim 3, wherein the second SCR catalyst is present in the layer that covers the surfaces in the second zone of the porous substrate and in a portion of the porous substrate in the second zone.

### Claim 6 (depends on 1)

The catalytic wall-flow monolith filter according to claim 1, wherein in the first zone, the first SCR catalyst does not cover a surface of the first or second pluralities of channels.

### Claim 7 (depends on 1)

The catalytic wall-flow monolith filter according to claim 1, wherein the first SCR catalyst is the same as the second SCR catalyst.

### Claim 8 (depends on 1)

The catalytic wall-flow monolith filter according to claim 1, wherein the first SCR catalyst is different than the second SCR catalyst.

### Claim 9 (depends on 1)

The catalytic wall-flow monolith filter according to claim 1, wherein at least one of the first SCR catalyst and the second SCR catalyst comprise a small-pore molecular sieve, a medium-pore molecular sieve, a large-pore molecular sieve, or a base metal.

### Claim 10 (depends on 9)

The catalytic wall-flow monolith filter of claim 9, wherein the small pore molecular sieve has a framework structure independently selected from the group consisting of AEI, AFT, CHA, DDR, EAB, ERI, GIS, GOO, KFI, LEV, LTA, MER, PAU, VNI and YUG.

### Claim 11 (depends on 9)

The catalytic wall-flow monolith filter of claim 9, wherein at least one of the first SCR catalyst and the second SCR catalyst comprises copper beta zeolite.

### Claim 12 (depends on 1)

The catalytic wall-flow monolith filter according to claim 1, wherein at least one of the first SCR catalyst and the second SCR catalyst comprises CeO2 impregnated with W, CeZrO2 impregnated with W, or ZrO2 impregnated with Fe and W.

### Claim 13 (depends on 1)

A catalytic wall-flow monolith filter according to claim 1, wherein the first SCR catalyst comprises a small-pore molecular sieve having a framework structure selected from the group consisting of AEI, AFT, CHA, DDR, EAB, ERI, GIS, GOO, KFI, LEV, LTA, MER, PAU, VNI and YUG structural families.

### Claim 14 (depends on 1)

A catalytic wall-flow monolith filter according to claim 1, wherein the second SCR catalyst is a large-pore molecular sieve or a non-zeolite material selected from CeO2 impregnated with W, CeZrO2 impregnated with W, and ZrO2 impregnated with Fe and W.

### Claim 15 (depends on 1)

A catalytic wall-flow monolith filter according to claim 1, wherein the ratio of a length of the second zone to a length of the first zone in the longitudinal direction is from 1:20 to 1:5.

### Claim 16 (depends on 1)

A catalytic wall-flow monolith filter according to claim 1, wherein the second SCR catalyst is present at from about 10% to about 50% of the length of the monolith substrate.

### Claim 17 (depends on 1)

A catalytic wall-flow monolith filter according to claim 1, wherein oxidation catalyst comprises a noble metal.

### Claim 18 (depends on 1)

A catalytic wall-flow monolith filter according to claim 1, further comprising a third zone located between the first zone and the second zone, wherein the third zone comprises the first SCR catalyst distributed throughout the porous substrate and the second SCR catalyst located in a layer that covers the surface of the porous substrate and is not distributed throughout the porous substrate.

### Claim 19 (depends on 18)

The catalytic wall-flow monolith filter according to claim 18, wherein the third zone has a length up to 10% of the length of the monolith substrate.

### Claim 20 (depends on 18)

A catalytic wall-flow monolith filter according to claim 18, further comprising a gap between at least a portion of: (a) the first zone and the second zone; (b) the first zone and the third zone; or (c) the third zone and the second zone.

### Claim 21 (depends on 18)

A catalytic wall-flow monolith filter according to claim 18, wherein there is no gap between at least a portion of: (a) the first zone and the second zone; (b) the first zone and the third zone; or (c) the third zone and the second zone.

### Claim 22 (depends on 1)

An emission treatment system for treating a flow of a combustion exhaust gas, the system comprising the catalytic wall-flow monolith filter according to claim 1, wherein the first end face is upstream of the second end face.

### Claim 23 (depends on 1)

A method for the manufacture of a catalytic wall-flow monolith filter of claim 1, the method comprising:
(a) providing a porous substrate having a first end face and a second end face defining a longitudinal direction therebetween and first and second pluralities of channels extending in the longitudinal direction, wherein the first plurality of channels is open at the first end face and closed at the second end face, and wherein the second plurality of channels is open at the second end face and closed at the first end face;
(b) forming a first zone by selectively infiltrating the porous substrate with a washcoat comprising the first SCR catalyst,
(c) forming the portion of the second zone comprising the ammonia oxidation catalyst by selectively infiltrating the porous substrate with a washcoat comprising an ammonia oxidation catalyst, and
(d) forming a coating of a second SCR catalyst over the ammonia oxidation catalyst in the second zone, where the walls of the second plurality of channels are covered by the coating,
wherein step (b) can be performed before step (c) or step (c) can be performed before step (b).

### Claim 24 (depends on 1)

A method for treating a flow of a combustion exhaust gas comprising NOx, the method comprising passing the exhaust stream through the monolith of claim 1, wherein the first end face is upstream of the second end face.