Exhaust gas purification catalyst

Patent metadata

Field	Value
Publication number	US-11559768-B2
Application number	US-202016851777-A
Country	US
Kind code	B2
Filing date	Apr 17, 2020
Priority date	May 9, 2019
Publication date	Jan 24, 2023
Grant date	Jan 24, 2023

Abstract

The present disclosure provides the exhaust gas purification catalyst with the improved purification performance under the high Ga condition and the transient state in which an A/F repeats rich and lean phases. The present disclosure relates to an exhaust gas purification catalyst comprising a catalyst coating layer on a substrate, the catalyst coating layer containing a noble metal, a composite oxide containing cerium oxide and zirconium oxide, and a composite oxide containing aluminum oxide, wherein in the catalyst coating layer: an average thickness of the coating layer is in a range from 20 μm to 100 μm; a porosity measured by a weight-in-water method is in a range from 50% by volume to 80% by volume; and high-aspect-ratio pores having an aspect ratio of 5 or more account for 0.5% by volume to 50% by volume of a whole volume of voids, the high-aspect-ratio pore having an equivalent circle diameter in a range from 2 μm to 50 μm in a cross-sectional image of a catalyst coating layer cross section perpendicular to an exhaust gas flow direction of the substrate and having an average aspect ratio in a range from 10 to 50, and wherein the noble metal is supported on peripheries of the voids, the composite oxide containing the cerium oxide and the zirconium oxide, and the composite oxide containing the aluminum oxide.

First claim

The invention claimed is:

1. An exhaust gas purification catalyst comprising a catalyst coating layer on a substrate, the catalyst coating layer containing a noble metal, a composite oxide containing cerium oxide and zirconium oxide, and a composite oxide containing aluminum oxide,
wherein in the catalyst coating layer:
an average thickness of the coating layer is in a range from 20 μm to 100 μm;
a porosity measured by a weight-in-water method is in a range from 50% by volume to 80% by volume; and
high-aspect-ratio pores having an aspect ratio of 5 or more account for 0.5% by volume to 50% by volume of a whole volume of voids, the high-aspect-ratio pores having an equivalent circle diameter in a range from 2 μm to 50 μm in a cross-sectional image of a catalyst coating layer cross section perpendicular to an exhaust gas flow direction of the substrate and having an average aspect ratio in a range from 10 to 50, and
wherein the noble metal is supported on peripheries of the voids, the composite oxide containing the cerium oxide and the zirconium oxide, and the composite oxide containing the aluminum oxide.

2. The exhaust gas purification catalyst according to claim 1 ,
wherein in the catalyst coating layer, the high-aspect-ratio pores are oriented such that a value of an 80% cumulative angle, in a cumulative angle distribution on an angle basis, of an angle cone angle between a vector in a longitudinal direction of the high-aspect-ratio pore and a vector in the exhaust gas flow direction of the substrate is in a range from 0 to 45 degrees.

3. The exhaust gas purification catalyst according to claim 1 ,
wherein in the catalyst coating layer, an amount of coating is in a range from 50 g/L to 300 g/L based on a unit volume of the substrate.

4. The exhaust gas purification catalyst according to claim 2 ,
wherein in the catalyst coating layer, an amount of coating is in a range from 50 g/L to 300 g/L based on a unit volume of the substrate.

Assignees

• Chinzei Isao
• Miura Masahide
• Nakahigashi Seiji
• Suzuki Hiromasa
• Morikawa Akira
• Yamamoto Toshio
• Katoh Satoru
• Onozuka Takashi
• Ori Hirotaka
• Okada Mitsuyoshi
• Hoshino Sho
• Toyota Motor Co Ltd
• Cataler Corp

Inventors

• Chinzei Isao
• Miura Masahide
• Nakahigashi Seiji
• Suzuki Hiromasa
• Morikawa Akira
• Yamamoto Toshio
• Katoh Satoru
• Onozuka Takashi
• Ori Hirotaka
• Okada Mitsuyoshi
• Hoshino Sho

Classifications

• B01J35/04

  Operations & Transport · mapped topic

• B01J23/40

  of the platinum group metals · CPC title

• F01N3/281

  Metallic honeycomb monoliths made of stacked or rolled sheets, foils or plates · CPC title

• B01D53/9459 Primary

  Removing one or more of nitrogen oxides, carbon monoxide, or hydrocarbons by multiple successive catalytic functions; systems with more than one different function, e.g. zone coated catalysts (layered catalysts with only one function B01D53/9413, B01D53/944 or B01D53/945) · CPC title

• B01J35/45

  Nanoparticles · CPC title