Catalyzed particulate filter

Patent metadata

Field	Value
Publication number	US-9381497-B2
Application number	US-201214346936-A
Country	US
Kind code	B2
Filing date	Aug 1, 2012
Priority date	Sep 22, 2011
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

A filter is configured for efficient combustion of particulates accumulated on a catalyst layer 7 in both a rapid combustion range and a slow combustion range. The catalyst layer 7 on an exhaust gas passage wall of a filter 1 includes a mixture of a Rh-doped Ce-containing composite oxide particle material loaded with Pt and a composite particle material loaded with Pt. In mixed particles of this mixture, Zr-containing composite oxide particles containing no Ce and activated alumina particles are mixed together and agglomerated.

First claim

The invention claimed is:

1. A catalyzed particulate filter comprising:
an exhaust gas passage wall on which particulates in exhaust gas are to be collected; and
a catalyst layer located on the exhaust gas passage wall and including Ce-containing composite oxide, Zr-containing composite oxide containing no Ce, activated alumina, and catalytic metals, wherein
the catalytic metals include Rh and Pt,
the Ce-containing composite oxide included in the catalyst layer is in a state of Rh-doped Ce-containing composite oxide particles containing Zr and Nd, doped with Rh as one of the catalytic metals, and having an oxygen storage/release capacity,
the Rh-doped Ce-containing composite oxide particles are loaded with Pt as one of the catalytic metals,
the Zr-containing composite oxide is Zr-containing composite oxide containing Nd and Pr and having an oxygen ion conduction,
the Zr-containing composite oxide and the activated alumina included in the catalyst layer are in a state of mixed particles in which Zr-containing composite oxide particles and activated alumina particles are mixed together and agglomerated,
the mixed particles are loaded with Pt as one of the catalytic metals, and
the Rh-doped Ce-containing composite oxide particles and the mixed particles are mixed such that a mass ratio among the Zr-containing composite oxide, the activated alumina, and the Rh-doped Ce-containing composite oxide is within a range enclosed by point A (18+3/4, 6+1/4, 75), point B (6+1/4, 18+3/4, 75), point C (22+2/9, 66+6/9, 11+1/9), and point D (66+6/9, 22+2/9, 11+1/9) in a triangular diagram of Zr-containing composite oxide, activated alumina, and Rh-doped Ce-containing composite oxide.

2. The catalyzed particulate filter of claim 1 , wherein
the Rh-doped Ce-containing composite oxide particles and the mixed particles are mixed such that the mass ratio among the Zr-containing composite oxide, the activated alumina, and the Rh-doped Ce-containing composite oxide is within a range enclosed by point A (18+3/4, 6+1/4, 75), point B (6+1/4, 18+3/4, 75), point E (16+2/3, 50, 33+1/3), and point F (50, 16+2/3, 33+1/3) in the triangular diagram.

3. The catalyzed particulate filter of claim 1 , wherein
a mass ratio Rh/Pt between Rh and Pt as the catalytic metals is greater than or equal to 1/1000 and less than or equal to 1/4.

4. The catalyzed particulate filter of claim 2 , wherein
a mass ratio Rh/Pt between Rh and Pt as the catalytic metals is greater than or equal to 1/1000 and less than or equal to 1/4.

5. The catalyzed particulate filter of claim 1 , wherein
the Zr-containing composite oxide particles constituting the mixed particles have an average particle size of 20-100 nm, and
the activated alumina particles constituting the mixed particles have an average particle size of 20-100 nm.

6. The catalyzed particulate filter of claim 2 , wherein
the Zr-containing composite oxide particles constituting the mixed particles have an average particle size of 20-100 nm, and
the activated alumina particles constituting the mixed particles have an average particle size of 20-100 nm.

7. The catalyzed particulate filter of claim 3 , wherein
the Zr-containing composite oxide particles constituting the mixed particles have an average particle size of 20-100 nm, and
the activated alumina particles constituting the mixed particles have an average particle size of 20-100 nm.

8. The catalyzed particulate filter of claim 4 , wherein
the Zr-containing composite oxide particles constituting the mixed particles have an average particle size of 20-100 nm, and
the activated alumina particles constituting the mixed particles have an average particle size of 20-100 nm.

Assignees

• Baba Takashi
• Harada Koichiro
• Yamada Hiroshi
• Shigetsu Masahiko
• Takami Akihide
• Mazda Motor

Inventors

• Baba Takashi
• Harada Koichiro
• Yamada Hiroshi
• Shigetsu Masahiko
• Takami Akihide

Classifications

• B01J2235/00

  Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties · CPC title

• B01J35/45

  Nanoparticles · CPC title

• B01J2235/30

  Scanning electron microscopy; Transmission electron microscopy · CPC title

• B01J35/56

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

• F01N3/10

  by thermal or catalytic conversion of noxious components of exhaust · CPC title