Catalyst for solid polymer fuel cell and method for producing same

Patent metadata

Field	Value
Publication number	US-2019221858-A1
Application number	US-201716329362-A
Country	US
Kind code	A1
Filing date	Sep 7, 2017
Priority date	Oct 10, 2016
Publication date	Jul 18, 2019
Grant date	—

Abstract

The present invention relates to a catalyst for a solid polymer fuel cell, including platinum, cobalt, and zirconium supported as a catalytic metal on a carbon powder carrier, in which the supporting ratio of platinum, cobalt, and zirconium on the carbon powder carrier is Pt:Co:Zr=3:0.5 to 1.5:0.1 to 3.0 by molar ratio. In the present invention, it is preferable that the peak position of Pt3Co seen in the X-ray diffraction pattern of catalyst particles is 2θ=41.10° or more and 42.00° or less, and moderate alloying has occurred in the catalytic metal.

First claim

1 . A catalyst for a solid polymer fuel cell, comprising platinum, cobalt, and zirconium supported as a catalytic metal on a carbon powder carrier,
wherein the supported ratio of platinum, cobalt, and zirconium on the carbon powder carrier is Pt:Co:Zr=3:0.5 to 1.5:0.1 to 3.0 by molar ratio.

2 . The catalyst for a solid polymer fuel cell according to claim 1 , wherein the supported ratio of platinum, cobalt, and zirconium on the carbon powder carrier is Pt:Co:Zr=3:0.5 to 1.5:0.2 to 1.8 by molar ratio.

3 . The catalyst for a solid polymer fuel cell according to claim 1 , wherein in a diffraction pattern obtained from the X-ray diffraction analysis of catalyst particles, the peak position of Pt 3 Co that appears in a region of 2θ=40.0° or more and 42.0° or less is 2θ=41.10° or more and 42.00° or less.

4 . The catalyst for a solid polymer fuel cell according to claim 1 , wherein in the diffraction pattern obtained from the X-ray diffraction analysis of catalyst particles, the ratio (I o /I a ) of the peak intensity of ZrO 2 (I o ) that appears in a region of 2θ=28.0° or more and 28.4° or less to the peak intensity of Pt 3 Co (la) that appears in a region of 2θ=40.0° or more and 42.0° or less is 1.3 or less.

5 . The catalyst for a solid polymer fuel cell according to claim 1 , wherein the catalytic metal is configured such that the surface concentrations of cobalt and zirconium are lower than the core concentrations of cobalt and zirconium.

6 . The catalyst for a solid polymer fuel cell according to claim 1 , wherein the supporting density of the catalytic metal is 30 mass % or more and 70 mass % or less.

7 . A method for producing the catalyst for a solid polymer fuel cell defined in claim 1 , comprising:
a step of supporting cobalt and zirconium on a platinum catalyst including platinum particles supported on a carbon powder carrier; a step of heat-treating the platinum catalyst having cobalt and zirconium supported thereon in the supporting step at 900° C. or more and 1,200° C. or less; and a step of bringing the heat-treated catalyst into contact with an oxidizing solution at least once to elute at least part of the supported cobalt and zirconium.

8 . The method for producing a catalyst for a solid polymer fuel cell according to claim 7 , wherein the oxidizing solution is a solution of sulfuric acid, nitric acid, phosphorous acid, potassium perzirconate, hydrogen peroxide, hydrochloric acid, chloric acid, hypochlorous acid, or chromic acid.

9 . The method for producing a catalyst for a solid polymer fuel cell according to claim 7 , wherein the contact treatment with the oxidizing solution is such that the treatment temperature is 40° C. or more and 90° C. or less, and the contact time is 1 hour or more and 10 hours or less.

10 . The catalyst for a solid polymer fuel cell according to claim 2 , wherein in a diffraction pattern obtained from the X-ray diffraction analysis of catalyst particles, the peak position of Pt 3 Co that appears in a region of 2θ=40.0° or more and 42.0° or less is 2θ=41.10° or more and 42.00° or less.

11 . The catalyst for a solid polymer fuel cell according to claim 2 , wherein in the diffraction pattern obtained from the X-ray diffraction analysis of catalyst particles, the ratio (I o /I a ) of the peak intensity of ZrO 2 (I o ) that appears in a region of 2θ=28.0° or more and 28.4° or less to the peak intensity of Pt 3 Co (I a ) that appears in a region of 2θ=40.0° or more and 42.0° or less is 1.3 or less.

12 . The catalyst for a solid polymer fuel cell according to claim 3 , wherein in the diffraction pattern obtained from the X-ray diffraction analysis of catalyst particles, the ratio (I o /I a ) of the peak intensity of ZrO 2 (I o ) that appears in a region of 2θ=28.0° or more and 28.4° or less to the peak intensity of Pt 3 Co (I a ) that appears in a region of 2θ=40.0° or more and 42.0° or less is 1.3 or less.

13 . The catalyst for a solid polymer fuel cell according to claim 2 , wherein the catalytic metal is configured such that the surface concentrations of cobalt and zirconium are lower than the core concentrations of cobalt and zirconium.

14 . The catalyst for a solid polymer fuel cell according to claim 3 , wherein the catalytic metal is configured such that the surface concentrations of cobalt and zirconium are lower than the core concentrations of cobalt and zirconium.

15 . The catalyst for a solid polymer fuel cell according to claim 4 , wherein the catalytic metal is configured such that the surface concentrations of cobalt and zirconium are lower than the core concentrations of cobalt and zirconium.

16 . The catalyst for a solid polymer fuel cell according to claim 2 , wherein the supporting density of the catalytic metal is 30 mass % or more and 70 mass % or less.

17 . The catalyst for a solid polymer fuel cell according to claim 3 , wherein the supporting density of the catalytic metal is 30 mass % or more and 70 mass % or less.

18 . A method for producing the catalyst for a solid polymer fuel cell defined in claim 2 , comprising:
a step of supporting cobalt and zirconium on a platinum catalyst including platinum particles supported on a carbon powder carrier; a step of heat-treating the platinum catalyst having cobalt and zirconium supported thereon in the supporting step at 900° C. or more and 1,200° C. or less; and a step of bringing the heat-treated catalyst into contact with an oxidizing solution at least once to elute at least part of the supported cobalt and zirconium.

19 . A method for producing the catalyst for a solid polymer fuel cell defined in claim 3 , comprising:
a step of supporting cobalt and zirconium on a platinum catalyst including platinum particles supported on a carbon powder carrier; a step of heat-treating the platinum catalyst having cobalt and zirconium supported thereon in the supporting step at 900° C. or more and 1,200° C. or less; and a step of bringing the heat-treated catalyst into contact with an oxidizing solution at least once to elute at least part of the supported cobalt and zirconium.

20 . The method for producing a catalyst for a solid polymer fuel cell according to claim 8 , wherein the contact treatment with the oxidizing solution is such that the treatment temperature is 40° C. or more and 90° C. or less, and the contact time is 1 hour or more and 10 hours or less.

Assignees

• Tanaka Precious Metal Ind

Inventors

• Hashimoto Wataru
• NAMAI Tatsunori
• Ishida Minoru
• Nakajima Hitoshi
• OKAYA Kazuki
• Kaieda Takeshi
• Matsutani Koichi

Classifications

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• H01M4/921 Primary

  Alloys or mixtures with metallic elements · CPC title

• H01M4/926 Primary

  on carbon or graphite · CPC title

• H01M4/8642

  Gradient in composition · 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