Exhaust gas purification catalyst

Patent metadata

Field	Value
Publication number	US-9925524-B2
Application number	US-201615211367-A
Country	US
Kind code	B2
Filing date	Jul 15, 2016
Priority date	Jul 17, 2015
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

The present disclosure provides an exhaust gas purification catalyst having improved performance for purifying an exhaust gas, in particular, an exhaust gas containing NOx. The exhaust gas purification catalyst of the present disclosure includes Rh-supporting composite oxide support particles containing Al, Zr, and Ti and Rh-supporting aluminum phosphate-based support particles. Furthermore, in the exhaust gas purification catalyst of the present disclosure, the ratio of the moles of metals constituting the aluminum phosphate-based support particles, relative to the total moles of metals constituting the composite oxide support particles and the aluminum phosphate-based support particles is 7.5% or more and 15.0% or less.

First claim

What is claimed is:

1. An exhaust gas purification catalyst comprising:
Rh-supporting composite oxide support particles containing Al, Zr, and Ti; and
Rh-supporting aluminum phosphate-based support particles,
wherein the aluminum phosphate-based support particles are support particles composed of aluminum phosphate in which a part of Al is substituted by Zr and the aluminum phosphate-based support particles are represented by the formula: Al α Zr (1-α) PO 4 , where α is 0.80 or more and less than 1.00, and
wherein the ratio of the mol number of metals constituting the aluminum phosphate-based support particles, relative to the total mol number of metals constituting the composite oxide support particles and the aluminum phosphate-based support particles, is 7.5% or more and 15.0% or less.

2. The exhaust gas purification catalyst according to claim 1 , further comprising Pt-supporting support particles.

3. The exhaust gas purification catalyst according to claim 2 , wherein the Pt-supporting support particles comprise composite oxide support particles containing Al, Zr, and Ti and/or composite oxide support particles containing Ce and Al.

4. The exhaust gas purification catalyst according to claim 3 , which is a catalyst for purifying NOx.

5. The exhaust gas purification catalyst according to claim 2 , which is a catalyst for purifying NOx.

6. The exhaust gas purification catalyst according to claim 1 , which is a catalyst for purifying NOx.

7. An exhaust gas purifying method, comprising:
bringing a NOx-containing exhaust gas into contact with an exhaust gas purification catalyst in a lean atmosphere to store NOx; and
reducing and purifying the NOx stored in the exhaust gas purification catalyst in a stoichiometric atmosphere or a rich atmosphere,
wherein the exhaust gas purification catalyst comprises:
Rh-supporting composite oxide support particles containing Al, Zr, and Ti; and
Rh-supporting aluminum phosphate-based support particles,
wherein the aluminum phosphate-based support particles are support particles composed of aluminum phosphate in which a part of Al is substituted by Zr and the aluminum phosphate-based support particles are represented by the formula: Al α Zr (1-α) PO 4 , and α is 0.80 or more and less than 1.00, and
wherein the ratio of the mol number of metals constituting the aluminum phosphate-based support particles, relative to the total mol number of metals constituting the composite oxide support particles and the aluminum phosphate-based support particles, is 7.5% or more and 15.0% or less.

8. The exhaust gas purifying method according to claim 7 , wherein the exhaust gas purification catalyst further comprises Pt-supporting support particles.

9. The exhaust gas purifying method according to claim 8 , wherein the Pt-supporting support particles comprise composite oxide support particles containing Al, Zr, and Ti and/or composite oxide support particles containing Ce and Al.

Assignees

• Toyota Motor Co Ltd

Inventors

• Sakano Mitsuru
• Inatomi Yusaku

Classifications

• B01D2255/40

  Mixed oxides · CPC title

• B01D2255/20715

  Zirconium · CPC title

• B01J27/16

  containing oxygen {, i.e. acids, anhydrides and their derivates with N, S, B or halogens without carriers or on carriers based on C, Si, Al or Zr; also salts of Si, Al and Zr} · CPC title

• B01D2255/1025

  Rhodium · CPC title

• B01D2255/1021

  Platinum · CPC title