Method for producing catalyst wherein catalyst particles having core/shell structure are supported

Patent metadata

Field	Value
Publication number	US-2018034062-A1
Application number	US-201615548193-A
Country	US
Kind code	A1
Filing date	Mar 2, 2016
Priority date	Mar 9, 2015
Publication date	Feb 1, 2018
Grant date	—

Abstract

A method for forming catalyst particles, each of which has a core/shell structure, by a Cu-UPD method. Namely, a method of manufacturing a catalyst wherein catalyst particles, each of which has a core/shell structure composed of a shell layer that is formed of platinum and a core particle that is covered with the shell layer and is formed of a metal other than platinum, are supported on a carrier. This method is characterized by comprising: an electrolysis step wherein the carrier supporting the core particles is electrolyzed in an electrolytic solution containing copper ions, so that copper is precipitated on the surfaces of the core particles; and a substitution reaction step wherein a platinum compound solution is brought into contact with the core particles, on which copper has been precipitated, so that the copper on the surface of each core particle is substituted by platinum, thereby forming a shell layer that is formed of platinum. This method is further characterized in that the platinum compound solution in the substitution reaction step contains citric acid.

First claim

1 . A method of manufacturing a catalyst comprising a catalytic particle supported on a carrier, the catalytic particle having a core/shell structure comprising: a shell layer comprising platinum; and a core particle covered with the shell layer and comprising a metal other than platinum, the method comprising the steps of:
subjecting said core-particle-supported carrier to electrolysis in a copper-ion-containing electrolytic solution, thereby depositing copper on a surface of the core particle, as an electrolytic treating process; and bringing a platinum compound solution into contact with the copper-deposited core particle to substitute the copper on the surface of the core particle with platinum, thereby forming a shell layer comprising platinum, as a substitution reaction process; wherein the platinum compound solution in the substitution reaction process contains organic acid, and an amount of dissolved oxygen in the electrolytic solution in the electrolytic treating process is controlled to 1 ppm or lower.

2 . The method of manufacturing a catalyst according to claim 1 , wherein a content of the citric acid in the platinum compound solution is 40-fold or less on the basis of the number of moles of the platinum compound.

3 . (canceled)

4 . The method of manufacturing a catalyst according to claim 1 , wherein the electrolytic treating process is an electrolytic treatment, which is conducted by accumulating the core-particle-supported carrier on a working electrode.

5 . The method of manufacturing a catalyst according to claim 1 , wherein a metal which constitutes the core particle is palladium, iridium, rhodium, gold, or an alloy of these metals.

6 . The method of manufacturing a catalyst according to claim 2 , wherein the electrolytic treating process is an electrolytic treatment, which is conducted by accumulating the core-particle-supported carrier on a working electrode.

7 . The method of manufacturing a catalyst according to claim 2 , wherein a metal which constitutes the core particle is palladium, iridium, rhodium, gold, or an alloy of these metals.

8 . The method of manufacturing a catalyst according to claim 4 , wherein a metal which constitutes the core particle is palladium, iridium, rhodium, gold, or an alloy of these metals.

Assignees

• Tanaka Precious Metal Ind

Inventors

• Matsutani Koichi
• Kaieda Takeshi
• Akiyama Tomohiro

Classifications

• B01J23/44

  Palladium · CPC title

• H01M4/86

  Inert electrodes with catalytic activity, e.g. for fuel cells · CPC title

• B01J37/348

  Electrochemical processes, e.g. electrochemical deposition or anodisation · CPC title

• H01M4/92

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

• H01M4/88

  Processes of manufacture · CPC title