Electrochemical catalysts with enhanced catalytic activity

Patent metadata

Field	Value
Publication number	US-11936051-B2
Application number	US-201916713890-A
Country	US
Kind code	B2
Filing date	Dec 13, 2019
Priority date	Jun 13, 2017
Publication date	Mar 19, 2024
Grant date	Mar 19, 2024

Abstract

A catalyst structure includes: (1) a substrate; (2) a catalyst layer on the substrate; and (3) an adhesion layer disposed between the substrate and the catalyst layer. In some implementations, an average thickness of the adhesion layer is about 1 nm or less. In some implementations, a material of the catalyst layer at least partially extends into a region of the adhesion layer. In some implementations, the catalyst layer is characterized by a lattice strain imparted by the adhesion layer.

First claim

What is claimed is:

1. A catalyst structure comprising:
a substrate;
a catalyst layer on the substrate, wherein the catalyst layer comprises a platinum group metal and has an average thickness of 8 nm or less; and
an adhesion layer disposed between the substrate and the catalyst layer, wherein the adhesion layer has an average thickness of 3 nm or less and comprises at least one of a metal oxide or a metalloid oxide, the metal oxide or metalloid oxide having oxygen vacancies;
wherein
the adhesion layer comprises an intermixed region comprising an alloy of the platinum group metal and metal atoms from the metal oxide or metalloid oxide, wherein the platinum group metal occupies at least some of the oxygen vacancies; and
wherein the intermixed region has a concentration gradient of the platinum group metal, wherein the platinum group metal in the intermixed region has a maximum concentration at an interface of the adhesion layer and the catalyst layer and a minimum concentration at 1 nm or less from an interface of the adhesion layer and the substrate.

2. The catalyst structure of claim 1 , wherein an average thickness of the adhesion layer is 1 nm to 2 nm.

3. The catalyst structure of claim 1 , wherein the catalyst layer is characterized by a lattice strain imparted by the adhesion layer.

4. The catalyst structure of claim 3 , wherein the adhesion layer includes a crystalline phase.

5. The catalyst structure of claim 1 , wherein the catalyst layer includes discrete regions that are spaced apart from one another, and at least one of the discrete regions includes a portion that is bonded to the substrate, and another portion that extends over the substrate and is spaced apart from the substrate by a gap.

6. The catalyst structure of claim 1 , further comprising an over-layer on the catalyst layer.

7. The catalyst structure of claim 6 , wherein an average thickness of the over-layer is 1 nm or less.

8. The catalyst structure of claim 6 , wherein the over-layer provides partial surface coverage of the catalyst layer.

9. The catalyst structure of claim 6 , wherein the catalyst layer includes a platinum group metal, and the over-layer includes an alloy of the platinum group metal and a material of the over-layer.

10. The catalyst structure of claim 6 , wherein the catalyst layer includes a platinum group metal, and the over-layer includes at least one of a metal oxide, a metalloid oxide, a metal nitride, a metalloid nitride, a metal carbide, a metalloid carbide, a metal boride, a metalloid boride, a metal sulfide, a metalloid sulfide, a metal phosphide, a metalloid phosphide, a metal silicide, or a metalloid silicide.

11. The catalyst structure of claim 6 , wherein a material of the catalyst layer at least partially extends into a region of the over-layer.

12. The catalyst structure of claim 1 , wherein the minimum concentration of the platinum group metal in the intermixed region is at the interface of the adhesion layer and the substrate, such that the platinum group metal has direct contact with the substrate.

13. The catalyst structure of claim 1 , wherein the platinum group metal is Pt.

14. The catalyst structure of claim 1 , wherein the adhesion layer comprises TiO 2 .

15. The catalyst structure of claim 1 , wherein the intermixed region comprises a Pt—Ti alloy.

16. The catalyst structure of claim 15 , wherein the Pt—Ti alloy comprises Pt 3 Ti.

17. A membrane electrode assembly for a fuel cell, comprising a polymeric ion-conductive membrane and an electrocatalyst layer adjacent to the polymeric ion-conductive membrane, wherein the electrocatalyst layer includes the catalyst structure of claim 1 .

18. A fuel cell comprising:
a cathode electrocatalyst layer;
an anode electrocatalyst layer; and
a polymeric ion-conductive membrane disposed between the cathode electrocatalyst layer and the anode electrocatalyst layer,
wherein at least one of the cathode electrocatalyst layer or the anode electrocatalyst layer includes the catalyst structure of claim 1 .

19. A fuel cell comprising:
a first gas diffusion layer;
a second gas diffusion layer; and
a polymeric ion-conductive membrane disposed between the first gas diffusion layer and the second gas diffusion layer,
wherein at least one of the first gas diffusion layer or the second gas diffusion layer includes the catalyst structure of claim 1 .

Assignees

• Univ Leland Stanford Junior
• Volkswagen Ag
• Volkswagen Aktiengesellschaf

Inventors

• Prinz Friedrich B
• Xu Shicheng
• Kim Yongmin
• Jaramillo Thomas
• Higgins Drew C
• Yusuf Maha
• Wang Zhaoxuan
• Lee Kyung Min
• Orazov Marat
• Lee Dong Un
• Graf Tanja
• Schladt Thomas
• Huebner Gerold
• Wittern Hanna-Lena
• Mueller Jonathan Edward

Classifications

• H01M4/926

  on carbon or graphite · CPC title

• H01M4/881

  Electrolytic membranes · CPC title

• H01M4/8892

  Impregnation or coating of the catalyst layer, e.g. by an ionomer · CPC title

• H01M4/8668

  Binders · CPC title

• H01M2300/0082

  Organic polymers · CPC title