Anode structure
An anode structure for incorporation into a fuel cell includes a first region having one or more electrocatalysts, in which the first region is adjacent to the fuel inlet when the anode structure is incorporated into a fuel cell, and a second region having one or more electrocatalysts, in which the second region is adjacent to the fuel outlet when the anode structure is incorporated into a fuel cell. The first region is better at promoting the electrochemical oxidation of carbon monoxide than the second region.
1. An anode structure for incorporation into a fuel cell comprising a fuel inlet and a fuel outlet, wherein the anode structure comprises:
a first region comprising an electrocatalyst of formula Pt—Y or Pt—Y—X, wherein Y is selected from the group consisting of Sn, Ti, V, Ta, Mo, W, Re or an oxide thereof, and X is one or more metals alloyed with the platinum, wherein the first region will be adjacent to the fuel inlet when the anode structure is incorporated into a fuel cell and wherein the first region covers between 5-50% of the surface area of the anode structure; and
a second region comprising an electrocatalyst of formula Pt—M for the electrochemical oxidation of hydrogen, wherein M is a metal alloyed with the platinum and is selected from the group consisting of Ru, Rh, Cr, Mn, Fe, Co, Ni, Cu, Ga, Zr and Hf, wherein the second region will be adjacent to the fuel outlet when the anode structure is incorporated into a fuel cell;
wherein the second region covers only that portion of the surface area of the anode structure not covered by the first region, the first region does not comprise the electrocatalyst of the second region, and the second region does not comprise the electrocatalyst of the first region; and
wherein the first region is better at promoting the electrochemical oxidation of carbon monoxide than the second region.
2. An anode structure according to claim 1 , wherein Y is selected from the group consisting of Sn, Ti, V, Ta, Mo, W and oxides thereof.
3. An anode structure according to claim 1 , wherein X is one or more metals selected from the group consisting of Ru, Rh, Ti, Cr, Mn, Fe, Co, Ni, Cu, V, Ga, Zr and Hf.
4. An anode structure according to claim 1 , wherein the first region comprises a Pt—Mo electrocatalyst.
5. An anode structure according to claim 1 , wherein the first region comprises only one electrocatalyst and the second region comprises only one electrocatalyst.
6. An anode structure according to claim 5 , wherein the first region comprises only one electrocatalyst, and the electrocatalyst is Pt—Mo, and the second region comprises only one electrocatalyst, and the electrocatalyst is Pt—Ru.
7. An anode structure according to claim 1 , comprising electrocatalysts on the surface of a gas diffusion substrate.
8. An anode structure according to claim 1 , comprising electrocatalysts on the surface of a polymer membrane.
9. A membrane electrode assembly comprising an anode structure according to claim 1 .
10. A fuel cell having a fuel inlet and a fuel outlet, wherein the fuel cell comprises an anode structure and the anode structure comprises
a first region comprising an electrocatalyst of formula Pt—Y or Pt—Y—X, wherein Y is selected from the group consisting of Sn, Ti, V, Ta, Mo, W, Re or an oxide thereof, and X is one or more metals alloyed with the platinum, wherein the first region is adjacent to the fuel inlet and wherein the first region covers between 5-50% of the surface area of the anode structure; and
a second region comprising an electrocatalyst of formula Pt—M for the electrochemical oxidation of hydrogen, wherein M is a metal alloyed with the platinum and is selected from the group consisting of Ru, Rh, Cr, Mn, Fe, Co, Ni, Cu, Ga, Zr and Hf, wherein the second region is adjacent to the fuel outlet, wherein the second region covers the remainder of the surface area of the anode structure not covered by the first region;
wherein the second region covers only that portion of the surface area of the anode structure not covered by the first region, the first region does not comprise the electrocatalyst of the second region, and the second region does not comprise the electrocatalyst of the first region; and
wherein the first region is better at promoting the electrochemical oxidation of carbon monoxide than the second region.
11. A method of using a fuel cell comprising the step of supplying a fuel cell according to claim 10 with reformate gas.
12. An anode structure according to claim 5 , comprising electrocatalysts on the surface of a gas diffusion substrate.
13. An anode structure according to claim 5 , comprising electrocatalysts on the surface of a polymer membrane.
14. A membrane electrode assembly comprising an anode structure according to claim 5 .