Composite oxide catalyst, porous composite, and method of producing composite oxide catalyst

Patent metadata

Field	Value
Publication number	US-11904298-B2
Application number	US-202017022441-A
Country	US
Kind code	B2
Filing date	Sep 16, 2020
Priority date	Sep 27, 2019
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

A composite oxide catalyst includes Ce that is a first metal, La that is a second metal, and a third metal as contained metals. The third metal is a transition metal, or a rare-earth metal other than Ce and La. A Ce content in the contained metals is higher than or equal to 5 mol % and lower than or equal to 95 mol %. An La content in the contained metals is higher than or equal to 2 mol % and lower than or equal to 93 mol %. A content of the third metal in the contained metals is higher than or equal to 2 mol % and lower than or equal to 93 mol %.

First claim

The invention claimed is:

1. A composite oxide catalyst comprising:
cerium that is a first metal, lanthanum that is a second metal, and a third metal as contained metals,
wherein said third metal is a transition metal, or a rare-earth metal other than cerium and lanthanum,
a cerium content in said contained metals is higher than 10 mol % of said contained metals and lower than or equal to 95 mol % of said contained metals,
a lanthanum content in said contained metals is higher than or equal to 2 mol % of said contained metals and lower than or equal to 93 mol % of said contained metals,
a content of said third metal in said contained metals is higher than or equal to 2 mol % of said contained metals and lower than or equal to 93 mol % of said contained metals,
said composite oxide catalyst substantially does not contain the elements of the platinum group, and
said composite oxide catalyst comprises particles including cavities when viewed in an SEM image at 5000× magnification.

2. The composite oxide catalyst according to claim 1 , wherein
the cerium content in said contained metals is higher than or equal to 50 mol % and lower than or equal to 95 mol %,
the lanthanum content in said contained metals is higher than or equal to 2 mol % and lower than or equal to 48 mol %, and
the content of said third metal in said contained metals is higher than or equal to 2 mol % and lower than or equal to 48 mol %.

3. The composite oxide catalyst according to claim 2 , wherein
said third metal is manganese or praseodymium, and
the lanthanum content in said contained metals is equal to the content of said third metal in said contained metals.

4. The composite oxide catalyst according to claim 1 , wherein said cavities have diameters greater than or equal to 0.2 μm and less than or equal to 5 μm.

5. A porous composite comprising:
a porous base material; and
a porous collection layer formed on said base material,
wherein said collection layer includes the composite oxide catalyst according to claim 1 .

6. The porous composite according to claim 5 , wherein
said base material has a honeycomb structure whose inside is partitioned into a plurality of cells by a partition wall, and
at least some of said plurality of cells have inner surfaces covered with said collection layer.

7. The porous composite according to claim 6 , being a filter that collects particulate matter in an exhaust gas emitted from a gasoline engine or a diesel engine.

8. A method of producing a composite oxide catalyst according to claim 1 , comprising:
preparing a mixed aqueous solution by mixing a nitrate of a raw metal and citric acid;
obtaining a precursor by heating said mixed aqueous solution; and
obtaining a composite oxide catalyst by firing said precursor,
wherein said raw metal includes cerium that is a first metal, lanthanum that is a second metal, and a third metal,
said third metal is a transition metal, or a rare-earth metal other than cerium and lanthanum,
a cerium content in said raw metal is higher than or equal to 5 mol % and lower than or equal to 95 mol %,
a lanthanum content in said raw metal is higher than or equal to 2 mol % and lower than or equal to 93 mol %, and
a content of said third metal in said raw metal is higher than or equal to 2 mol % and lower than or equal to 93 mol %.

Assignees

• Ngk Insulators Ltd

Inventors

• Nakashima Takuya
• Izumi Yunie

Classifications

• B01J23/34 Primary

  Manganese · CPC title

• B01J23/10

  of rare earths · CPC title

• B01J35/0006

  Operations & Transport · mapped topic

• B01J35/04

  Operations & Transport · mapped topic

• B01J35/10

  Operations & Transport · mapped topic