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1. WO2020193958 - CATALYST FOR A FUEL CELL

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

Claims:

1. A process for preparing a catalyst precursor, said process comprising the steps of:

(i) providing PtaXb alloy particles on a support material;

(ii) applying a shell of X to the PtaXb alloy particles to provide a catalyst precursor comprising particles having a PtaXb core and an X shell;

wherein the ratio of a to b is in the range of and including 10:1 to 1 :2.5; and

wherein X is Co, Ni, Y, Gd, Sc or Cu.

2. A process according to claim 1 , wherein step (ii) is performed by carrying out a controlled surface reaction.

3. A process according to claim 1 or claim 2, wherein X is Co, Ni or Cu.

4. A process according to claim 1 or claim 2, wherein X is Y, Gd or Sc.

5 A process according to any preceding claim, wherein the ratio of a to b is in the range of and including 5:1 to 1 :2.5.

6. A process for preparing a catalyst material, said process comprising the steps of:

(i) providing PtaXb alloy particles on a support material;

(ii) applying a shell of X to the PtaXb alloy particles to provide a catalyst precursor comprising particles having a PtaXb core and an X shell; then

(iii) heating the catalyst precursor at a temperature of no more than 900°C; then

(iv) subjecting the material produced in step (iii) to conditions sufficient to leach a portion of metal X from the material;

wherein the ratio of a to b is in the range of and including 10:1 to 1 :2.5; and

wherein X is Co, Ni, Y, Gd, Sc or Cu.

7. A process according to claim 6, wherein in step (iii) the catalyst precursor is heated at a temperature of at least 150°C.

8. A process according to claim 6 or claim 7, wherein step (ii) is performed by carrying out a controlled surface reaction.

9. A process according any of claims 6 to 8, wherein X is Co, Ni or Cu.

10. A process according to any of claims 6 to 8, wherein X is Y, Gd or Sc.

11. A process according to any of claims 6 to 10, wherein the ratio of a to b is in the range of and including 5:1 to 1 :2.5.

12. A process according to any of claims 6 to 11 , wherein step (iv) is carried out by acid washing.

13. A catalyst material obtainable by the process according to any of claims 6 to 12.

14. A catalyst layer comprising a catalyst material according to claim 13.

15. A catalyst coated membrane comprising the catalyst layer of claim 14 and an ion conducting membrane.

16. A gas diffusion electrode comprising the catalyst layer of claim 14 and a gas diffusion layer.

17. A membrane electrode assembly comprising the catalyst layer of claim 14, the catalyst coated membrane of claim 15, or the gas diffusion electrode of claim 16.

18. A fuel cell comprising the catalyst layer of claim 14, the catalyst coated membrane of claim 15, the gas diffusion electrode of claim 16, or the membrane electrode assembly of claim 17.