Exhaust cleaning catalyst

Patent metadata

Field	Value
Publication number	US-9597663-B2
Application number	US-201415030448-A
Country	US
Kind code	B2
Filing date	Dec 8, 2014
Priority date	Dec 11, 2013
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

An exhaust cleaning catalyst, with which precious metal sintering is inhibited and which has greater exhaust cleaning abilities, has a substrate and a catalyst coating layer provided on the substrate. The catalyst coating layer has a precious metal that serves as an oxidation and/or reduction catalyst. The precious metal has Rh-containing metal particles in which rhodium (Rh) coexists with a base metal selected among platinum group elements excluding rhodium. The Rh-containing metal particles have an average rhodium content of 0.1% to 5% by mole with the total amount of the base metal and rhodium being 100% by mole.

First claim

The invention claimed is:

1. An exhaust cleaning catalyst comprising a substrate and a catalyst coating layer on the substrate, wherein
the catalyst coating layer comprises a precious metal that serves as an oxidation and/or reduction catalyst, and a carrier that carries the precious metal,
the precious metal comprises Rh-containing metal particles in which rhodium (Rh) coexists with a base metal selected among platinum group elements excluding rhodium,
each of the Rh-containing metal particles has both a crystal phase of the base metal and a crystal phase of Rh, and
the Rh-containing metal particles has an average rhodium content of 0.1% to 5% by mole with the total amount of the base metal and rhodium being 100% by mole based on energy dispersive X-ray spectrometry analysis of a scanning transmission electron microscopy image.

2. The exhaust cleaning catalyst according to claim 1 , wherein the base metal is palladium.

3. The exhaust cleaning catalyst according to claim 1 , wherein the average rhodium content is 1% to 3% by mole.

4. The exhaust cleaning catalyst according to claim 1 , wherein the Rh-containing metal particles have an average particle diameter of 1 nm to 5 nm based on scanning transmission electron microscopy.

5. The exhaust cleaning catalyst according to claim 1 , wherein the carrier comprises an alumina-based oxide and/or a ceria-zirconia-based composite oxide.

6. The exhaust cleaning catalyst according to claim 5 , wherein the carrier further comprises a rare earth oxide and/or an alkaline earth metal oxide.

7. The exhaust cleaning catalyst according to claim 1 , wherein the precious metal comprises elemental Rh particles in addition to the Rh-containing metal particles.

8. The exhaust cleaning catalyst according to claim 7 having a ratio of number of moles of Rh particles that coexist in the Rh-containing metal particles to number of moles of the elemental Rh of 0.001 to 0.4.

9. The exhaust cleaning catalyst according to claim 1 , wherein the average rhodium content is 1.5% to 2.5% by mole.

10. The exhaust cleaning catalyst according to claim 1 , wherein the Rh-containing metal particles have an average particle diameter of 1 nm to 3 nm based on scanning transmission electron microscopy.

11. The exhaust cleaning catalyst according to claim 7 having a ratio of number of moles of Rh particles that coexist in the Rh-containing metal particles to number of moles of the elemental Rh of 0.005 to 0.35.

12. The exhaust cleaning catalyst according to claim 7 having a ratio of number of moles of Rh particles that coexist in the Rh-containing metal particles to number of moles of the elemental Rh of 0.001 to 0.35.

Assignees

• Cataler Corp

Inventors

• Inoda Satoru
• Hirai Akimasa
• Taki Kenichi
• Matsueda Satoshi

Classifications

• B01J35/34

  Mechanical properties · CPC title

• 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

• B01D2255/1025

  Rhodium · CPC title

• B01D53/945

  characterised by a specific catalyst · CPC title