Use of an anode catalyst layer
A method of operating a fuel cell having an anode, a cathode and a polymer electrolyte membrane disposed between the anode and the cathode, includes feeding the anode with an impure hydrogen stream having low levels of carbon monoxide up to 5 ppm, and wherein the anode includes an anode catalyst layer including a carbon monoxide tolerant catalyst material, wherein the catalyst material includes: (i) a binary alloy of PtX, wherein X is a metal selected from the group consisting of rhodium and osmium, and wherein the atomic percentage of platinum in the alloy is from 45 to 80 atomic % and the atomic percentage of X in the alloy is from 20 to 55 atomic %; and (ii) a support material on which the PtX alloy is dispersed; wherein the total loading of platinum group metals (PGM) in the anode catalyst layer is from 0.01 to 0.2 mgPGM/cm 2 .
1. A method of operating a fuel cell comprising an anode, a cathode and a polymer electrolyte membrane disposed between the anode and the cathode, wherein said method comprises feeding the anode with an impure hydrogen stream comprising carbon monoxide in an amount of between 2 ppm to 5 ppm, and wherein the anode comprises an anode catalyst layer comprising a carbon monoxide tolerant catalyst material, wherein the catalyst material comprises:
(i) a binary alloy of PtX, wherein X is rhodium, and wherein the atomic percentage of platinum in the alloy is from 45 to 80 atomic % and the atomic percentage of X in the alloy is from 20 to 55 atomic %; and
(ii) a support material on which the PtX alloy is dispersed;
wherein the total loading of platinum group metals (PGM) in the anode catalyst layer is from 0.01 to 0.2 mgPGM/cm 2 , wherein the fuel cell produces stable voltages when the anode is fed an impure catalyst stream comprising 5 ppm of carbon monoxide.
2. The method according to claim 1 , wherein the atomic percentage of Pt in the binary alloy is from 50 to 75 atomic % and the atomic percentage of X is from 25 to 50 atomic %.
3. The method according to claim 1 , wherein the amount of platinum in the supported catalyst is 10-50 wt % of the total weight of the binary alloy plus support material.
4. The method according to claim 1 , wherein the anode further comprises a second catalyst.
5. The method according to claim 4 , wherein the second catalyst is an oxygen evolution catalyst.
6. The method according to claim 2 , wherein the atomic percentage of Pt in the binary alloy is from 50 to 75 atomic % and the atomic percentage of X is from 25 to 50 atomic %.
7. The method according to claim 2 , wherein the amount of platinum in the supported catalyst is 10-50 wt % of the total weight of the binary alloy plus support material.
8. The method according to claim 2 , wherein the anode further comprises a second catalyst.
9. The method according to claim 3 , wherein the anode further comprises a second catalyst.
10. The method according to claim 8 , wherein the second catalyst is an oxygen evolution catalyst.
11. The method according to claim 9 , wherein the second catalyst is an oxygen evolution catalyst.