Carbon supported catalyst
A catalyst includes (i) a primary metal or alloy or mixture including the primary metal, and (ii) an electrically conductive carbon support material for the primary metal or alloy or mixture including the primary metal, wherein the carbon support material: (a) has a specific surface area (BET) of 100-600 m 2 /g, and (b) has a micropore area of 10-90 m 2 /g.
1. An electrode comprising a gas diffusion layer and a catalyst, wherein the catalyst comprises:
(i) a primary metal, or an alloy or mixture comprising the primary metal, and
(ii) an electrically conductive carbon support material for said primary metal, alloy or mixture, wherein the carbon support material:
(a) has a specific surface area (BET) of 300-600 m 2 /g, and
(b) has a micropore area of 25-60 m 2 /g.
2. The electrode according to claim 1 , wherein the carbon support material loses 20% or less of its mass in an accelerated test involving a 1.2V potential hold over a 24 hour period at 80° C.
3. The electrode according to claim 1 , wherein the carbon support material has a specific corrosion rate of less than 65%.
4. The electrode according to claim 2 , wherein the carbon support material has a specific corrosion rate of less than 65%.
5. The electrode according to claim 1 , wherein the primary metal is selected from the group consisting of
(i) the platinum group metals of platinum, palladium, rhodium, ruthenium, iridium and osmium,
(ii) gold, silver, and
(iii) a base metal
or an oxide thereof.
6. The electrode according to claim 1 , wherein the primary metal has a gas phase metal area of at least 30 m 2 /g.
7. The electrode according to claim 1 , wherein the loading of primary metal particles on the carbon support material is in the range 5-95 wt %.
8. A catalysed membrane comprising a solid polymeric membrane and a catalyst, the catalyst comprising:
(i) a primary metal, or an alloy or mixture comprising the primary metal, and
(ii) an electrically conductive carbon support material for said primary metal, alloy or mixture, wherein the carbon support material:
(a) has a specific surface area (BET) of 300-600 m 2 /g,
(b) has a micropore area of 25-60 m 2 /g.
9. A catalysed transfer substrate comprising a transfer substrate and the catalyst as defined in claim 1 .
10. A membrane electrode assembly comprising the electrode as claimed in claim 1 .
11. A fuel cell comprising the membrane electrode assembly as claimed in claim 10 .
12. A fuel cell comprising the electrode according to claim 1 .
13. The electrode according to claim 1 , wherein the primary metal is platinum.
14. The fuel cell according to claim 11 , wherein the fuel cell is a proton exchange membrane fuel cell and the loading of primary metal particles on the carbon support material is in the range of 35-75 wt %.
15. The fuel cell according to claim 11 , wherein the fuel cell is a phosphoric acid fuel cell and the loading of primary metal particles on the carbon support material is in the range 5-25 wt %.
16. The catalyzed membrane according to claim 8 , wherein the carbon support material loses 20% or less of its mass in an accelerated test involving a 1.2V potential hold over a 24 hour period at 80° C.
17. The catalyzed membrane according to claim 8 , wherein the carbon support material has a specific corrosion rate of less than 65%.
18. The catalyzed membrane according to claim 8 , wherein the primary metal is selected from the group consisting of
(i) the platinum group metals of platinum, palladium, rhodium, ruthenium, iridium and osmium,
(ii) gold, silver, and
(iii) a base metal
or an oxide thereof.
19. The catalyzed membrane according to claim 8 , wherein the primary metal has a gas phase metal area of at least 30 m 2 /g.
20. The catalyzed membrane according to claim 8 , wherein the loading of primary metal particles on the carbon support material is in the range 5-95 wt %.
21. A membrane electrode assembly comprising the catalyzed membrane according to claim 8 .
22. A fuel cell comprising the membrane electrode assembly according to claim 21 .
23. A fuel cell comprising the catalyzed membrane according to claim 8 .
24. The catalyzed membrane according to claim 8 , wherein the primary metal is platinum.
25. The fuel cell according to claim 22 , wherein the fuel cell is a proton exchange membrane fuel cell and the loading of primary metal particles on the carbon support material is in the range of 35-75 wt %.
26. The fuel cell according to claim 22 , wherein the fuel cell is a phosphoric acid fuel cell and the loading of primary metal particles on the carbon support material is in the range 5-25 wt %.
27. The electrode according to claim 1 , wherein the electrically conductive carbon support material comprises carbon black, and the carbon black has been treated with at least one gas selected from the group consisting of oxygen, ozone, hydrogen peroxide, nitrogen dioxide, air, carbon dioxide and steam.
28. The electrode according to claim 27 , wherein the carbon black is treated at a temperature between 800° C. and 1100° C.
29. The electrode according to claim 27 , wherein the carbon black is treated for a time ranging between 30 minutes and 4 hours.
30. The catalyzed membrane according to claim 8 , wherein the electrically conductive carbon support material comprises carbon black, and the carbon black has been treated with at least one gas selected from the group consisting of oxygen, ozone, hydrogen peroxide, nitrogen dioxide, air, carbon dioxide and steam.
31. The catalyzed membrane according to claim 30 , wherein the carbon black is treated at a temperature between 800° C. and 1100° C.
32. The catalyzed membrane according to claim 30 , wherein the carbon black is treated for a time ranging between 30 minutes and 4 hours.