Method for producing core-shell catalyst particles

Patent metadata

Field	Value
Publication number	US-2016359173-A1
Application number	US-201415117314-A
Country	US
Kind code	A1
Filing date	Dec 22, 2014
Priority date	Feb 14, 2014
Publication date	Dec 8, 2016
Grant date	—

Abstract

The present invention is to provide a method for producing core-shell catalyst particles with high catalytic activity per unit mass of platinum. Disclosed is a method for producing core-shell catalyst particles including a core containing palladium and a shell containing platinum and covering the shell, wherein the method includes: a step of depositing copper on the surface of the palladium-containing particles by applying a potential that is nobler than the oxidation-reduction potential of copper to the palladium-containing particles in a copper ion-containing electrolyte, and a step of forming the shell by, after the copper deposition step and inside the reaction system kept at −3° C. or more and 10° C. or less, substituting the copper deposited on the surface of the palladium-containing particles with platinum by bringing the copper into contact with a platinum ion-containing solution in which platinum ions and a reaction inhibitor that inhibits a substitution reaction between the copper and the platinum, are contained.

First claim

1 . A method for producing core-shell catalyst particles comprising a core containing palladium and a shell containing platinum and covering the shell,
wherein the method comprises:
a step of depositing copper on the surface of the palladium-containing particles by applying a potential that is nobler than the oxidation-reduction potential of copper to the palladium-containing particles in a copper ion-containing electrolyte, and
a step of forming the shell by, after the copper deposition step and inside the reaction system kept at −3° C. or more and 10° C. or less, substituting the copper deposited on the surface of the palladium-containing particles with platinum by bringing the copper into contact with a platinum ion-containing solution in which platinum ions and a reaction inhibitor that inhibits a substitution reaction between the copper and the platinum, are contained,
and wherein the reaction inhibitor is at least one selected from the group consisting of citric acid, ethylenediaminetetraacetic acid (EDTA), sodium salts thereof, and potassium salts thereof.

2 . (canceled)

3 . The method for producing the core-shell particles according to claim 1 , wherein the method comprises a step of bringing an acid solution into contact with the palladium-containing particles subjected to the substitution of the copper with the platinum, after the substitution step.

4 . The method for producing the core-shell particles according to claim 3 , wherein the acid solution contains at least one selected from the group consisting of sulfuric acid, perchloric acid, nitric acid, hydrochloric acid and hypochlorous acid.

5 . The method for producing the core-shell particles according to claim 1 , wherein the palladium-containing particles are supported on a support.

Assignees

• Toyota Motor Co Ltd

Inventors

• Kaneko Keiichi
• Kimura Hiroko
• Adachi Makoto

Classifications

• B22F1/17

  Metallic particles coated with metal · CPC title

• H01M4/8878

  Treatment steps after deposition of the catalytic active composition or after shaping of the electrode being free-standing body · CPC title

• C23C18/42 Primary

  Coating with noble metals · CPC title

• C23C18/1848

  by electrochemical pretreatment · CPC title

• H01M4/8825

  Methods for deposition of the catalytic active composition · CPC title