Method for Manufacturing Platinum Catalyst, and Fuel Cell Including the Same

Patent metadata

Field	Value
Publication number	US-2018047993-A1
Application number	US-201615554470-A
Country	US
Kind code	A1
Filing date	Mar 8, 2016
Priority date	Mar 10, 2015
Publication date	Feb 15, 2018
Grant date	—

Abstract

A platinum core-shell catalyst that uses palladium (Pd) as a core metal, or a platinum catalyst containing platinum and a metal besides platinum is manufactured industrially on a mass scale. The platinum catalyst is supported on carbon and has excellent oxygen reduction activity. The platinum catalyst is made for a fuel cell by bringing about the presence of a chemical species imparting higher potential than the initial oxide formation potential of the platinum of the platinum catalyst, and by bringing about the presence of a chemical species imparting lower potential than the initial oxide formation potential of the platinum of the platinum catalyst. The manufacture is carried out in a dispersion solution of the platinum catalyst dispersed in an acidic solution containing protons.

First claim

1 . A method for manufacturing a platinum catalyst for fuel cells that contains platinum and a non-platinum metal, comprising the steps of:
(I) allowing a chemical species that generates a potential higher than an onset potential of Pt oxide formation to be present; and (II) allowing a chemical species that generates a potential lower than an onset potential of reduction of Pt oxide to be present in a dispersion solution including the platinum catalyst dispersed in an acidic solution containing protons.

2 . The manufacturing method according to claim 1 , wherein steps (I) and (II) are carried out alternately a plurality of times.

3 . The manufacturing method according to claim 1 , wherein steps (I) and (II) are each carried out for a predetermined duration.

4 . The manufacturing method according to claim 3 , wherein the predetermined duration is within a range of 1 to 30 minutes.

5 . The manufacturing method according to claim 1 , wherein steps (1) and (II) are each a step of allowing a gas and/or a solid to be present in the dispersion solution.

6 . The manufacturing method according to claim 1 , wherein
step (I) is (A) a step of feeding a gas that generates a potential higher than the onset potential of Pt oxide formation, and step (II) is (B-1) a step of feeding a gas that generates a potential lower than the onset potential of reduction of Pt oxide.

7 . The manufacturing method according to claim 6 , wherein in step (B-1), the gas that generates a potential lower than the onset potential of reduction of Pt oxide is hydrogen.

8 . The manufacturing method according to claim 1 , wherein
step (I) is (A) a step of feeding a gas that generates a potential higher than the onset potential of Pt oxide formation., and step (II) is (B-2) a step of feeding an inert gas while allowing a solid that generates a potential lower than the onset potential of reduction of Pt oxide to be present in the dispersion solution.

9 . The manufacturing method according to claim 8 , wherein in step (B-2), the solid that generates a potential lower than the onset potential of reduction of Pt oxide is copper, and the inert gas is argon gas or nitrogen gas.

10 . The manufacturing method according to claim 6 , wherein in step (A), the gas that generates a potential higher than the onset potential of Pt oxide formation is a gas containing oxygen.

11 . The manufacturing method according to claim 1 , wherein the acidic solution containing protons is a sulfuric acid solution.

12 . The manufacturing method according to claim 1 , further comprising, between step (I) and step (II), the step of: (III) feeding inert gases.

13 . The manufacturing method according to claim 1 , wherein the platinum catalyst is a platinum core-shell catalyst having palladium-containing core particles and platinum shells formed on surfaces of the core particles.

14 . The manufacturing method according to claim 1 , wherein the platinum catalyst is a platinum alloy catalyst of platinum and palladium, cobalt, nickel, iron or copper.

15 . A platinum catalyst manufactured by the method according to claim 1 .

16 . A fuel cell comprising a platinum catalyst manufactured by the method according to claim 1 as a catalyst for an oxygen reduction reaction.

17 . A method for improving activity of a platinum catalyst for fuel cells, comprising dispersing a platinum catalyst in an acidic solution, and repeatedly carrying out the following steps in order a plurality of times:
(1) a step of feeding inert gases into a platinum catalyst dispersed solution, (2) a step of feeding hydrogen into the platinum catalyst dispersed solution, (3) a step of feeding inert gases into the platinum catalyst dispersed solution, and (4) a step of feeding oxygen into the platinum catalyst dispersed solution.

18 . A method for improving activity of a platinum catalyst for fuel cells, comprising dispersing a platinum catalyst in an acidic solution, and repeatedly carrying out the following steps in order a plurality of times:
(101) a step of feeding inert gases into a platinum catalyst dispersed solution, (102) a step of allowing solid copper to be present in the platinum catalyst dispersed solution while feeding inert gases into the platinum catalyst dispersed solution, (103) a step of removing the solid copper of step (102) from the platinum catalyst dispersed solution, and (104) a step of feeding oxygen into the platinum catalyst dispersed solution.

Assignees

• The Doshisha
• Ishifuku Metal Ind

Inventors

• Inaba Minoru
• Daimon Hideo
• Okuno Kosuke
• Higuchi Shunya
• Matsui Yuki
• Aoki Naoya
• Inoue Hideo
• Nishikawa Takehito

Classifications

• H01M4/88 Primary

  Processes of manufacture · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M4/926

  on carbon or graphite · CPC title

• H01M4/921 Primary

  Alloys or mixtures with metallic elements · CPC title

• Y02E60/50

  Fuel cells · CPC title