Method for producing core-shell catalyst

Patent metadata

Field	Value
Publication number	US-10305113-B2
Application number	US-201515329057-A
Country	US
Kind code	B2
Filing date	Jun 3, 2015
Priority date	Jul 31, 2014
Publication date	May 28, 2019
Grant date	May 28, 2019

Abstract

A core-shell catalyst with high platinum mass activity for a short period of time. The method for producing a core-shell catalyst may comprise a core containing palladium and a shell containing platinum and coating the core, the method comprising: a step of preparing a copper-coated palladium-containing particle dispersion in which copper-coated palladium-containing particles are dispersed, the particles being palladium-containing particles coated with copper; a step of preparing a platinum ion-containing solution; a step of preparing a microreactor; and a substitution step of forming the shell by substituting the copper on the copper-coated palladium-containing particle surface with platinum by mixing the copper-coated palladium-containing particle dispersion and the platinum ion-containing solution in the microreactor.

First claim

The invention claimed is:

1. A method for producing a core-shell catalyst comprising a core containing palladium and a shell containing platinum and coating the core, the method comprising:
a step of preparing a copper-coated palladium-containing particle dispersion in which copper-coated palladium-containing particles are dispersed, the particles being palladium-containing particles coated with copper;
a step of preparing a platinum ion-containing solution; and
a substitution step of forming the shell by substituting the copper on the copper-coated palladium-containing particle surface with platinum by mixing the copper-coated palladium-containing particle dispersion and the platinum ion-containing solution in a microreactor.

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

3. The method for producing the core-shell catalyst according to claim 1 , wherein the platinum ion-containing solution comprises a reaction inhibitor for inhibiting a substitution reaction of platinum ions with the copper and the platinum.

4. The method for producing the core-shell catalyst according to claim 3 , wherein the reaction inhibitor is at least one selected from the group consisting of citric acid, sodium citrate and potassium citrate.

5. The method for producing the core-shell catalyst according to claim 4 , wherein a citric acid ion concentration of the platinum ion-containing solution is in a range of 0.5 to 2 mol/L.

6. The method for producing the core-shell catalyst according to claim 1 , wherein the mixing in the substitution step is carried out under a pressure condition of 5 to 200 MPa.

7. A method for producing a core-shell catalyst comprising a core containing palladium and a shell containing platinum and coating the core, the method comprising:
a step of preparing a copper-coated palladium-containing particle dispersion in which copper-coated palladium-containing particles are dispersed, the particles being palladium-containing particles coated with copper;
a step of preparing a platinum ion-containing solution; and
a substitution step of forming the shell by substituting the copper on the copper-coated palladium-containing particle surface with platinum by mixing the copper-coated palladium-containing particle dispersion and the platinum ion-containing solution in a microreactor and stirring the mixed solution thus obtained in nitrogen atmosphere after the mixing.

8. The method for producing the core-shell catalyst according to claim 7 , wherein the mixing in the substitution step is carried out under a pressure condition of 25 to 200 MPa inside a junction of the microreactor.

9. A method for producing a core-shell catalyst comprising a core containing palladium and a shell containing platinum and coating the core, the method comprising:
a step of preparing a copper-coated palladium-containing particle dispersion in which copper-coated palladium-containing particles are dispersed, the particles being palladium-containing particles coated with copper;
a step of preparing a platinum ion-containing solution; and
a substitution step of forming the shell by substituting the copper on the copper-coated palladium-containing particle surface with platinum by mixing the copper-coated palladium-containing particle dispersion and the platinum ion-containing solution in a microreactor,
wherein the platinum ion-containing solution comprises at least one selected from the group consisting of citric acid, sodium citrate and potassium citrate, and
wherein a citric acid ion concentration in the mixture obtained by mixing the copper-coated palladium particle dispersion and the platinum ion-containing solution is 0.05 to 2 mol/L with respect to a mass concentration of the copper-coated palladium-containing particles of 1 g/L.

10. The method for producing a core-shell catalyst according to claim 9 , wherein the citric acid ion concentration in the mixture obtained by mixing the copper-coated palladium particle dispersion and the platinum ion-containing solution is more than 0.4 mol/L and less than 2 mol/L with respect to a mass concentration of the copper-coated palladium-containing particles of 1 g/L.

Assignees

• Toyota Motor Co Ltd

Inventors

• Hori Yoshihiro
• Ishikawa Shotaro

Classifications

• H01M4/88

  Processes of manufacture · CPC title

• Y02E60/50

  Fuel cells · CPC title

• H01M4/8657 Primary

  layered · CPC title

• H01M4/92

  Metals of platinum group (H01M4/94 {, H01M4/9058} take precedence) · CPC title

• H01M4/926

  on carbon or graphite · CPC title