Fuel cell electrocatalyst of Pt-Rh-Mo-Ni/Fe

1. A catalyst for use in oxidation or reduction reactions, the catalyst composition comprising platinum, rhodium, molybdenum, and nickel, iron, or a combination of nickel and iron, wherein the concentration of platinum therein is between about 10 and about 50 atomic percent.

2. The catalyst of claim 1 consisting essentially of platinum, rhodium, molybdenum, and nickel or iron.

3. The catalyst of claim 1 wherein the concentration of rhodium is between about 0.1 and about 50 atomic percent, the concentration of molybdenum is between about 0.1 and about 55 atomic percent, and the concentration of nickel, iron, or a combination of nickel and iron is between about 0.1 and about 55 atomic percent.

4. The catalyst of claim 3 wherein the concentration of platinum is between about 20 and about 50 atomic percent, the concentration of rhodium is between about 5 and about 25 atomic percent, the concentration of molybdenum is between about 5 and about 45 atomic percent, the concentration of nickel is between about 5 and about 55 atomic percent.

5. The catalyst of claim 4 wherein the sum of the concentrations of platinum and rhodium is between about 40 and about 50 atomic percent.

6. The catalyst of claim 4 wherein the concentration of platinum is between about 30 and about 40 atomic percent, the concentration of rhodium is between about 5 and about 10 atomic percent, the concentration of molybdenum Is between about 5 and about 35 atomic percent, and the concentration of nickel is between about 25 and about 50 atomic percent.

7. The catalyst of claim 3 wherein the concentration of platinum is from about 10 to about 30 atomic percent, the concentration of rhodium is from about 10 to about 30 atomic percent, the concentration of molybdenum is from about 30 to about 55 atomic percent and the concentration of iron is from about 10 to about 30 atomic percent.

8. The catalyst of claim 7 wherein the concentration of platinum is from about 15 to about 25 atomic percent, the concentration of rhodium is from about 15 to about 25 atomic percent, the concentration of molybdenum is from about 35 to about 45 atomic percent and the concentration of iron is from about 15 to about 25 atomic percent.

9. An alloy comprising platinum, rhodium, molvbdenum, and nickel, iron, or a combination of nickel and iron, wherein the concentration of platinum therein is between about 10 and about 50 atomic percent.

10. The alloy of claim 9 consisting essentially of platinum, rhodium, molybdenum, and nickel or iron.

11. The alloy of claim 9 wherein the concentration of platinum is between about 20 and about 50 atomic percent, the concentration of rhodium is between about 5 and about 25 atomic percent, the concentration of molybdenum is between about 5 and about 45 atomic percent, the concentration of nickel is between about 5 and about 55 atomic percent.

12. The alloy of claim 11 wherein the sum of the concentrations of platinum and rhodium is between about 40 and about 50 atomic percent.

13. The alloy of claim 11 wherein the concentration of platinum is between about 30 and about 40 atomic percent, the concentration of rhodium is between about 5 and about 10 atomic percent, the concentration of molybdenum is between about 5 and about 35 atomic percent, and the concentration of nickel is between about 25 and about 50 atomic percent.

14. The alloy of claim 9 wherein the concentration of platinum is from about 10 to about 30 atomic percent, the concentration of rhodium is from about 10 to about 30 atomic percent, the concentration of molybdenum is from about 30 to about 55 atomic percent and the concentration of iron is from about 10 to about 30 atomic percent.

15. The alloy of claim 14 wherein the concentration of platinum is from about 15 to about 25 atomic percent, the concentration of rhodium is from about 15 to about 25 atomic percent, the concentration of molybdenum is from about 35 to about 45 atomic percent and the concentration of iron is from about 15 to about 25 atomic percent.

16. A supported electrocatalyst particle for use in electrochemical reactor devices, the supported electrocatalyst particle comprising an electrocatalyst and an electrically conductive support particle upon which the electrocatalyst is dispersed, the electrocatalyst comprising platinum, rhodium, molybdenum, and nickel, iron, or a combination of nickel and iron, wherein the concentration of platinum is between about 10 and about 50 atomic percent.

17. The supported electrocatalyst particle of claim 16 wherein the electrically conductive support particle is selected from the group consisting of oil furnace black, acetylene black, graphite paper, carbon fabric and carbon aerogel.

18. The supported electrocatalyst particle of claim 16 wherein the electrocatalyst consists essentially of platinum, rhodium, molybdenum, and nickel or iron.

19. The supported electrocatalyst particle of claim 16 wherein the concentration of platinum is between about 20 and about 50 atomic percent, the concentration of rhodium is between about 5 and about 25 atomic percent, the concentration of molybdenum is between about 5 and about 45 atomic percent, the concentration of nickel is between about 5 and about 55 atomic percent.

20. The supported electrocatalyst particle of claim 19 wherein the sum of the concentrations of platinum and rhodium is between about 40 and about 50 atomic percent.

21. The supported electrocatalyst particle of claim 19 wherein the concentration of platinum is between about 30 and about 40 atomic percent, the concentration of rhodium is between about 5 and about 10 atomic percent, the concentration of molybdenum is between about 5 and about 35 atomic percent, and the concentration of nickel is between about 25 and about 50 atomic percent.

22. The supported electrocatalyst particle of claim 16 wherein the concentration of platinum is from about 10 to about 30 atomic percent, the concentration of rhodium is from about 10 to about 30 atomic percent, the concentration of molybdenum is from about 30 to about 55 atomic percent and the concentration of iron is from about 10 to about 30 atomic percent.

23. The supported electrocatalyst particle of claim 22 wherein the concentration of platinum is from about 15 to about 25 atomic percent, the concentration of rhodium is from about 15 to about 25 atomic percent, the concentration of molybdenum is from about 35 to about 45 atomic percent and the concentration of iron is from about 15 to about 25 atomic percent.