Exhaust gas purification catalyst

Patent metadata

Field	Value
Publication number	US-11053833-B2
Application number	US-202016857566-A
Country	US
Kind code	B2
Filing date	Apr 24, 2020
Priority date	May 9, 2019
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

The present disclosure provides the exhaust gas purification catalyst with the improved purification performance under the high Ga condition and the atmosphere where the A/F is rich. The present disclosure relates to an exhaust gas purification catalyst including a catalyst coating layer on a substrate, the catalyst coating layer containing a noble metal and a metal oxide, wherein in the catalyst coating layer: an average thickness of the coating layer is in a range from 50 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 when a surface side in contact with an exhaust gas in a thickness direction of the catalyst coating layer is defined as 0% and a side in contact with the substrate is defined as 100%, 80% by mass or more of a total amount of the noble metal is present in a range from 0% to 25% or more and 70% or less.

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 and a metal oxide,
wherein in the catalyst coating layer:
an average thickness of the coating layer is in a range from 50 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 when a surface side in contact with an exhaust gas in a thickness direction of the catalyst coating layer is defined as 0% of thickness and a side in contact with the substrate is defined as 100% of thickness, 80% or more of a total amount by mass of the noble metal is present in a range from 25% of thickness or more and 70% of thickness or less.

2. The exhaust gas purification catalyst according to claim 1 ,
wherein in the catalyst coating layer, the high-aspect-ratio pore is 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 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.

4. The exhaust gas purification catalyst according to claim 3 ,
wherein when a surface side in contact with the exhaust gas is defined as 0% of thickness and a side in contact with the substrate is defined as 100% in the thickness direction of the catalyst coating layer, 80% or more of a total amount by mass of the noble metal is present in a range from 27% of thickness or more and 66% of thickness or less.

5. The exhaust gas purification catalyst according to claim 2 ,
wherein when a surface side in contact with the exhaust gas is defined as 0% of thickness and a side in contact with the substrate is defined as 100% in the thickness direction of the catalyst coating layer, 80% or more of a total amount by mass of the noble metal is present in a range from 27% of thickness or more and 66% of thickness or less.

6. 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.

7. The exhaust gas purification catalyst according to claim 6 ,
wherein when a surface side in contact with the exhaust gas is defined as 0% and a side in contact with the substrate is defined as 100% in the thickness direction of the catalyst coating layer, 80% by mass or more of a total amount of the noble metal is present in a range from 27% or more and 66% or less.

8. The exhaust gas purification catalyst according to claim 1 ,
wherein when a surface side in contact with the exhaust gas is defined as 0% of thickness and a side in contact with the substrate is defined as 100% in the thickness direction of the catalyst coating layer, 80% or more of a total amount by mass of the noble metal is present in a range from 27% of thickness or more and 66% of thickness or less.

Assignees

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

Inventors

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

Classifications

• B01J35/56

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

• B01J2523/00

  Constitutive chemical elements of heterogeneous catalysts · CPC title

• B01D2255/1025

  Rhodium · CPC title

• F01N2510/068

  characterised by the distribution of the catalytic coatings · CPC title

• B01J37/0215

  Coating · CPC title