Surface modified platinum or platinum alloy catalyst for oxygen reduction reaction

Patent metadata

Field	Value
Publication number	US-11322750-B2
Application number	US-201916563376-A
Country	US
Kind code	B2
Filing date	Sep 6, 2019
Priority date	Apr 24, 2019
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

An oxygen reduction reaction (ORR) catalyst, a membrane-electrode assembly and a polymer electrolyte membrane fuel cell containing the catalyst are provided. The ORR catalyst is a solid catalyst on a carbon support and the solid catalyst contains platinum metal or a platinum alloy metal having a surface complexed with a monodentate thiol ligand comprising an aromatic or heteroaromatic ring containing at least one of a bromide and an iodide substituent.

First claim

The invention claimed is:

1. An oxygen reduction reaction (ORR) catalyst, consisting of:
a solid platinum metal, solid platinum metal alloy or a combination of a solid platinum metal and solid platinum alloy; and
a carbon support;
wherein the solid platinum metal and/or platinum alloy metal has a surface complexed with a monodentate thiol ligand comprising an aromatic or heteroaromatic ring containing at least one of a bromide and an iodide substituent.

2. The ORR catalyst according to claim 1 , wherein the monodentate thiol ligand comprises an aromatic ring and the aromatic ring is a phenylene group.

3. The ORR catalyst according to claim 2 , wherein the monodentate thiol ligand is a thiophenol substituted with at least one of a bromide group and an iodide group.

4. The ORR catalyst according to claim 1 , wherein the monodentate thiol ligand comprises a heteroaromatic ring and the heteroaromatic ring is a 5 or 6 membered ring containing at least one of N, O and S.

5. The ORR catalyst according to claim 4 , wherein the heteroaromatic ring is one selected from the group consisting of furan, thiophene, pyrrole, pyridine, pyrimidine and pyrazine.

6. The ORR catalyst according to claim 5 , wherein the monodentate thiol ligand is a mercaptopyridine substituted with at least one of a bromide group and an iodide group.

7. The ORR catalyst according to claim 4 , wherein the monodentate thiol ligand is 5-bromopyridine-2-thiol.

8. The ORR catalyst according to claim 1 , wherein the wherein a surface of the Pt metal available for catalyst activity is at least 50% of a total Pt surface area.

9. The ORR catalyst according to claim 1 , wherein the solid catalyst further comprises an alloy metal.

10. The ORR catalyst according to claim 9 , wherein the alloy metal is selected from the group consisting of the transition metals.

11. The ORR catalyst according to claim 10 , wherein the alloy metal is selected from the group consisting of Fe, Co, Ni and Cu.

12. The ORR catalyst according to claim 11 , wherein the alloy metal is Co.

13. The ORR catalyst according to claim 1 wherein the carbon support comprises a conductive carbon.

14. The ORR catalyst according to claim 13 , wherein the conductive carbon is selected from the group consisting of carbon black, acetylene black, synthetic graphite, natural flake graphite, carbon nanotubes, fullerenes, hard carbon, and mesoporous carbon.

15. A membrane-electrode assembly for oxygen reduction, comprising:
a solid catalyst layer comprising the ORR catalyst according to claim 1 , wherein
the solid catalyst layer is disposed between an ionomeric membrane and a gas diffusion layer.

16. A polymer electrolyte fuel cell comprising the membrane-electrode assembly of claim 15 .

Assignees

• Toyota Eng & Mfg North America

Inventors

• Ikehata Yuta
• Kobayashi Masaya
• Nagai Tomoyuki
• Jia Hongfei
• Kato Hisao

Classifications

• H01M4/926

  on carbon or graphite · CPC title

• H01M8/1004 Primary

  characterised by membrane-electrode assemblies [MEA] (H01M8/12 takes precedence) · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M4/9008 Primary

  Organic or organo-metallic compounds · CPC title

• Y02E60/50

  Fuel cells · CPC title