# US 9,005,559 B2 · Oxidation catalyst for internal combustion engine exhaust gas treatment

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- Number: US 9,005,559 B2
- Document ID: US9005559B2
- Status: Granted
- Kind: B2
- Application number: 14/158,889
- Filed: 2014-01-20
- Published: 2014-05-15
- Granted: 2015-04-14
- Earliest claimed: 2011-10-06
- Assignees: Johnson Matthey Public Limited Company; Johnson Matthey Japan Godo Kaisha
- Applicants: Johnson Matthey Japan G.K.; Johnson Matthey Public Limited Company
- Inventors: Satoshi Sumiya; Lifeng Wang; Hanako Oyamada; Philip Gerald Blakeman; Gavin Michael Brown; Sougato Chatterjee; Andrew Francis Chiffey; Jane Gast; Paul Richard Phillips; Raj Rao Rajaram; Andrew Peter Walker
- Web page: https://patentgrep.com/patent/US9005559B2

## CPC

- B01J 29/763: {CHA-type, e.g. Chabazite, LZ-218}
- B01D 53/944: {Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts (three-way-catalysts [TWC] B01D53/9445)}
- B01J 20/18: Synthetic zeolitic molecular sieves
- B01J 21/04: Alumina
- B01J 21/12: Silica and alumina
- B01J 23/42: Platinum
- B01J 23/44: Palladium
- B01J 29/06: Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- B01J 29/068: Noble metals
- B01J 29/7007: {Zeolite Beta}
- B01J 29/7415: {Zeolite Beta}
- B01J 29/7615: {Zeolite Beta}
- 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 37/0244: {Coatings comprising several layers}
- B01J 37/0246: {Coatings comprising a zeolite}
- B01J 37/038: {to form slurries or suspensions, e.g. a washcoat}
- F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent}
- F01N 3/2803: {characterised by structure, by material or by manufacturing of catalyst support}
- B01D 53/9431: {Processes characterised by a specific device}
- B01D 53/9477: {with catalysts positioned on separate bricks, e.g. exhaust systems}
- B01D 2253/108: Zeolites
- B01D 2255/1021: Platinum
- B01D 2255/1023: Palladium
- B01D 2255/2065: Cerium
- B01D 2255/207: Transition metals
- B01D 2255/20707: Titanium
- B01D 2255/50: Zeolites
- B01D 2255/902: Multilayered catalyst
- B01D 2255/9022: Two layers
- B01D 2255/912: HC-storage component incorporated in the catalyst
- B01D 2258/012: Diesel engines and lean burn gasoline engines
- B01J 2229/186: not in framework positions
- Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
- Y02T 10/12: Improving ICE efficiencies
- Y10S 502/52712: Plural layers on a support, each layer having a distinct function
- 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)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

The invention provides an exhaust gas cleaning oxidation catalyst and in particular to an oxidation catalyst for cleaning the exhaust gas discharged from internal combustion engines of compression ignition type (particularly diesel engines). The invention further relates to a catalysed substrate monolith comprising an oxidising catalyst on a substrate monolith for use in treating exhaust gas emitted from a lean-burn internal combustion engine. In particular, the invention relates to a catalysed substrate monolith comprising a first washcoat coating and a second washcoat coating, wherein the second washcoat coating is disposed in a layer above the first washcoat coating.

## Claims

### Claim 1

A catalysed substrate monolith for treating exhaust gas emitted from a lean-burn internal combustion engine comprising an oxidising catalyst on a substrate monolith, wherein the catalysed substrate monolith comprises a first washcoat coating having a length L and a second washcoat coating, wherein the second washcoat coating is disposed in a layer above the first washcoat coating for at least some of length L, wherein the first washcoat coating comprises a catalyst composition comprising platinum (Pt) and at least one support material for the platinum, wherein the second washcoat coating comprises a catalyst composition comprising both platinum (Pt) and palladium (Pd) and at least one support material for the platinum and the palladium and wherein a weight ratio of platinum (Pt) to palladium (Pd) in the second washcoat coating is ≦2.

### Claim 2 (depends on 1)

The catalysed substrate monolith according to claim 1, wherein the substrate monolith is a flow-through substrate monolith.

### Claim 3 (depends on 1)

The catalysed substrate monolith according to claim 1, wherein the weight ratio of platinum (Pt) to palladium (Pd) in the second washcoat coating is ≦1:1.

### Claim 4 (depends on 1)

The catalysed substrate monolith according to claim 1, wherein the second washcoat coating comprises both platinum (Pt) and palladium (Pd) and wherein the first washcoat coating comprises both platinum (Pt) and palladium (Pd) at a higher Pt:Pd weight ratio than in the second washcoat coating.

### Claim 5 (depends on 1)

The catalysed substrate monolith according to claim 1, wherein a Pt:Pd weight ratio of both the first washcoat coating and the second washcoat coating combined is ≦1:1.

### Claim 6 (depends on 1)

The catalysed substrate monolith according to claim 1, wherein a Pt:Pd weight ratio of both the first washcoat coating and the second washcoat coating combined is ≦10:1.

### Claim 7 (depends on 1)

The catalysed substrate monolith according to claim 1, wherein the first washcoat coating comprises 25-75% by weight of the total platinum group metal present in the first washcoat coating and the second washcoat coating combined.

### Claim 8 (depends on 1)

The catalysed substrate monolith according to claim 1, wherein the at least one support material of the first washcoat coating or the second washcoat coating comprises a metal oxide selected from the group consisting of optionally stabilised alumina, amorphous silica-alumina, optionally stabilised zirconia, ceria, titania, an optionally stabilised ceria-zirconia mixed oxide, a molecular sieve, and a mixture of any two or more thereof.

### Claim 9 (depends on 1)

The catalysed substrate monolith according to claim 1, wherein the oxidising catalyst is a diesel oxidation catalyst or a NOx adsorber catalyst.

### Claim 10 (depends on 1)

The catalysed substrate monolith according to claim 1, wherein a Pt:Pd weight ratio of both the first washcoat coating and the second washcoat coating combined is ≦2:1.

### Claim 11 (depends on 1)

An exhaust system for a lean-burn internal combustion engine, which system comprises a first catalysed substrate monolith according to claim 1.

### Claim 12 (depends on 11)

The exhaust system according to claim 11, comprising a second catalysed substrate monolith comprising a selective catalytic reduction (SCR) catalyst, which second catalysed substrate monolith being disposed downstream from the first catalysed substrate monolith.

### Claim 13 (depends on 12)

The exhaust system according to claim 12 comprising an injector for injecting a nitrogenous reductant into exhaust gas between the first catalysed substrate monolith and the second catalysed substrate monolith.

### Claim 14 (depends on 12)

The exhaust system according to claim 12 comprising a third catalysed substrate monolith, wherein the substrate monolith of the first catalysed substrate monolith is a flow-through substrate monolith, wherein the third catalysed substrate monolith is a filtering substrate monolith having inlet surfaces and outlet surfaces and wherein the inlet surfaces are separated from the outlet surfaces by a porous structure, which third catalysed substrate monolith comprises an oxidation catalyst and is disposed between the first catalysed substrate monolith and the second catalysed substrate monolith.

### Claim 15 (depends on 14)

The exhaust system according to claim 14 comprising an injector for injecting a nitrogenous reductant into exhaust gas between the first catalysed substrate monolith and the second catalysed substrate monolith, wherein the injector for injecting a nitrogenous reductant into exhaust gas is disposed to inject nitrogenous reductant into exhaust gas between the third catalysed substrate monolith and the second catalysed substrate monolith.

### Claim 16 (depends on 12)

The exhaust system according to claim 12 comprising a third substrate monolith, wherein the third substrate monolith is a filtering substrate monolith having inlet surfaces and outlet surfaces, wherein the inlet surfaces are separated from the outlet surfaces by a porous structure, which third substrate monolith is disposed downstream of the second catalysed substrate monolith.

### Claim 17 (depends on 16)

The exhaust system according to claim 16, wherein the third substrate monolith comprises an oxidation catalyst.

### Claim 18 (depends on 12)

The exhaust system according to claim 12, wherein the second catalysed substrate monolith is a filtering substrate monolith having inlet surfaces and outlet surfaces, wherein the inlet surfaces are separated from the outlet surfaces by a porous structure.

### Claim 19 (depends on 18)

The exhaust system according to claim 18, wherein the filtering substrate monolith is a wall-flow filter.

### Claim 20 (depends on 11)

A lean-burn internal combustion engine, comprising an exhaust system according to claim 11.

### Claim 21

A method of reducing or preventing a selective catalytic reduction (SCR) catalyst in an exhaust system of a lean-burn internal combustion engine from becoming poisoned with platinum which may volatilise from a first washcoat coating having a length L comprising a catalyst composition comprising platinum (Pt) and at least one support material for the platinum disposed on a substrate monolith upstream of the SCR catalyst when the catalyst composition comprising platinum is exposed to relatively extreme conditions including relatively high temperatures, which method comprising trapping volatilised platinum in a second washcoat coating disposed in a layer above the first washcoat coating for at least some of the length L, which second washcoat coating comprising a catalyst composition comprising both platinum (Pt) and palladium (Pd) and at least one support material for the platinum and the palladium and wherein a weight ratio of platinum to palladium in the second washcoat coating is ≦2.