# US 10,307,736 B2 · Exhaust gas purification catalyst

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- Number: US 10,307,736 B2
- Document ID: US10307736B2
- Status: Granted
- Kind: B2
- Application number: 15/936,980
- Filed: 2018-03-27
- Published: 2018-10-25
- Granted: 2019-06-04
- Earliest claimed: 2017-04-19
- Assignees: Toyota Jidosha Kabushiki Kaisha; Cataler Corporation
- Applicants: Yoshinori Saito; Hiromasa Suzuki; Tatsuya Ohashi; Keiichi Narita; Ryota Nakashima; Mitsuyoshi Okada; Ryosuke Takasu; Shunsuke Oishi
- Inventors: Yoshinori Saito; Hiromasa Suzuki; Tatsuya Ohashi; Keiichi Narita; Ryota Nakashima; Mitsuyoshi Okada; Ryosuke Takasu; Shunsuke Oishi
- Web page: https://patentgrep.com/patent/US10307736B2

## CPC

- B01J 23/464: {Rhodium}
- B01D 53/945: {characterised by a specific catalyst}
- B01D 53/9468: {in different layers}
- B01J 21/04: Alumina
- B01J 21/066: {Zirconium or hafnium; Oxides or hydroxides thereof}
- B01J 23/44: Palladium
- B01J 23/63: with rare earths or actinides
- B01J 35/19: {Catalysts containing parts with different compositions}
- B01J 37/0236: {Drying, e.g. preparing a suspension, adding a soluble salt and drying}
- B01J 37/0244: {Coatings comprising several layers}
- B01J 37/0248: {Coatings comprising impregnated particles}
- F01N 3/0814: {combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts}
- F01N 3/101: {Three-way catalysts}
- F01N 13/16: Selection of particular materials
- B01D 2255/1021: Platinum
- B01D 2255/1023: Palladium
- B01D 2255/1025: Rhodium
- B01D 2255/9022: Two layers
- B01D 2255/9025: Three layers
- B01J 37/088: {Decomposition of a metal salt}
- F01N 2510/068: characterised by the distribution of the catalytic coatings
- F01N 2510/0684: having more than one coating layer, e.g. multi-layered coatings
- F01N 2570/12: Hydrocarbons
- F01N 2570/14: Nitrogen oxides
- 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
- 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

## Abstract

An exhaust gas purification catalyst, excellent in the NOx purification capacity and the HC purification capacity, includes a substrate and a catalyst coating layer formed on the surface of the substrate, wherein the catalyst coating layer comprises the upper and lower layer including a lower layer being closer to the surface of the substrate and an upper layer being relatively remote from the surface of the substrate. The upper layer of the catalyst coating layer includes Rh, Pd, and a carrier. The lower layer of the catalyst coating layer includes at least one noble metal selected from Pd and Pt and a carrier. 65% by mass or more of Pd in the upper layer exists in a layer up to 50% of the upper layer in a thickness direction from the surface of the upper layer being relatively remote from the surface of the substrate. The ratio of Pd to Rh by mass (Pd/Rh) is 0.5 to 7.0 in the upper layer.

## Claims

### Claim 1

An exhaust gas purification catalyst comprising a substrate and a catalyst coating layer formed on the surface of the substrate,
wherein the catalyst coating layer comprises the upper and lower layer comprising a lower layer being closer to the surface of the substrate and an upper layer being relatively remote from the surface of the substrate,
the upper layer of the catalyst coating layer comprises Rh and Pd, and a carrier,
the lower layer of the catalyst coating layer comprises at least one noble metal selected from Pd and Pt, and a carrier,
65% by mass or more of Pd in the upper layer exists in a layer up to 50% of the upper layer in a thickness direction from the surface of the upper layer being relatively remote from the surface of the substrate, and
the ratio of Pd to Rh by mass (Pd/Rh) in the upper layer is 0.5 to 7.0.

### Claim 2 (depends on 1)

The exhaust gas purification catalyst according to claim 1, wherein 85% by mass or more of Pd in the upper layer exists in a layer up to 50% of the upper layer in a thickness direction from the surface of the upper layer being relatively remote from the surface of the substrate.