Method for producing core-shell catalyst

Patent metadata

Field	Value
Publication number	US-2017214060-A1
Application number	US-201515313264-A
Country	US
Kind code	A1
Filing date	Apr 3, 2015
Priority date	May 28, 2014
Publication date	Jul 27, 2017
Grant date	—

Abstract

The disclosure is to provide a method for producing a core-shell catalyst that is able to increase the power generation performance of a membrane electrode assembly. A dispersion is prepared, in which a palladium-containing particle support, in which palladium-containing particles are supported on an electroconductive support, is dispersed in water; hydrogen gas is bubbled into the dispersion; the palladium-containing particles are acid treated after the bubbling; copper is deposited 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 after the acid treatment; and then a shell is formed by substituting the copper deposited on the surface of the palladium-containing particles with platinum by bringing the copper deposited on the surface of the palladium-containing particles into contact with a platinum ion-containing solution.

First claim

What is claimed is:

1 . A method for producing a core-shell catalyst comprising a core containing palladium and a shell containing platinum and covering the core,
wherein the method comprises:
a step of preparing a dispersion in which a palladium-containing particle support, in which palladium-containing particles are supported on an electroconductive support, is dispersed in water;
a bubbling step of bubbling hydrogen gas into the dispersion;
an acid treatment step of acid treating the palladium-containing particles after the bubbling step;
a copper deposition 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 after the acid treatment step; and
a substitution step of forming the shell by substituting the copper deposited on the surface of the palladium-containing particles after the copper deposition step with platinum by bringing the copper deposited on the surface of the palladium-containing particles into contact with a platinum ion-containing solution.

2 . The method for producing the core-shell catalyst according to claim 1 , wherein the method further comprises a boil-washing step of boil-washing the palladium-containing particles with water after the acid treatment step and before the copper deposition step.

3 . The method for producing the core-shell catalyst according to claim 1 , wherein the acid is at least one selected from the group consisting of sulfuric acid and nitric acid.

4 . The method for producing the core-shell catalyst according to claim 1 , wherein the electroconductive support comprises at least one of a carbonaceous material and a metal material.

Assignees

• Toyota Motor Co Ltd

Inventors

• Kitao Noriyuki
• Sasaki Naoyuki
• Fujisawa Tsugio

Classifications

• C25D5/34

  Pretreatment of metallic surfaces to be electroplated · CPC title

• C25D5/48

  After-treatment of electroplated surfaces · CPC title

• C25D3/38

  of copper · CPC title

• H01M4/925

  supported on carriers, e.g. powder carriers · CPC title

• H01M4/8853 Primary

  Electrodeposition · CPC title