Catalytic converter

Patent metadata

Field	Value
Publication number	US-9839902-B2
Application number	US-201615042877-A
Country	US
Kind code	B2
Filing date	Feb 12, 2016
Priority date	Mar 23, 2015
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

A catalytic converter with excellent OSC performance and NO x purification performance. The converter includes a substrate with a cell structure through which exhaust gas flows, and a catalyst layer formed on a cell wall surface of the substrate. The catalyst layer includes a lower catalyst layer and an upper catalyst layer, the lower catalyst layer being formed on a surface of the substrate, and the upper catalyst layer being formed on a surface of the lower catalyst layer. The upper catalyst layer includes at least a zirconia support with rhodium carried thereon, and two types of ceria-zirconia-based composite oxides with different specific surface areas, each of the ceria-zirconia-based composite oxides having no rhodium carried thereon. The lower catalyst layer includes an alumina support with platinum carried thereon, and a ceria-zirconia-based composite oxide.

First claim

What is claimed is:

1. A catalytic converter comprising:
a substrate with a cell structure through which exhaust gas flows; and
a catalyst layer formed on a cell wall surface of the substrate,
wherein the catalyst layer includes a lower catalyst layer and an upper catalyst layer, the lower catalyst layer being formed on a surface of the substrate, and the upper catalyst layer being formed on a surface of the lower catalyst layer,
the upper catalyst layer includes at least a zirconia support with rhodium carried thereon, and two types of ceria-zirconia-based composite oxides with different specific surface areas, each of the ceria-zirconia-based composite oxides having no rhodium carried thereon, and
the lower catalyst layer includes an alumina support with platinum carried thereon, and a ceria-zirconia-based composite oxide,
of the two types of ceria-zirconia-based composite oxides with different specific surface areas, the ceria-zirconia-based composite oxide with a larger specific surface area has a specific surface area of greater than or equal to 40 m 2 /g, and the ceria-zirconia-based composite oxide with a smaller specific surface area has a specific surface area of less than or equal to 4 m 2 /g,
wherein, of the two types of ceria-zirconia-based composite oxides with different specific surface areas,
the ceria-zirconia-based composite oxide with a larger specific surface area is contained in the upper catalyst layer by an amount of greater than or equal to 12 g/L, and
the ceria-zirconia-based composite oxide with a smaller specific surface area is contained in the upper catalyst layer by an amount of greater than or equal to 8 g/L.

2. The catalytic converter according to claim 1 , wherein the zirconia support with rhodium carried thereon is contained in the upper catalyst layer by an amount of 40 g/L.

Assignees

• Toyota Motor Co Ltd

Inventors

• Suzuki Hiromasa
• Yoshida Takeru
• Saito Yoshinori
• Okada Mitsuyoshi

Classifications

• B01J35/56

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

• B01J23/63 Primary

  with rare earths or actinides · CPC title

• B01D2255/9022

  Two layers · CPC title

• B01D2255/407

  Zr-Ce mixed oxides · CPC title

• B01D2255/1025

  Rhodium · CPC title