ELECTRODES WITH IMPROVED CELL REVERSAL TOLERANCE THROUGH FUNCTIONALIZED AND STABILIZED METAL OXIDES
A method for manufacturing a functionalized metal oxide product configured to be used in an anode catalyst layer of a fuel cell can include forming a catalyst solution, which can include mixing a metal oxide in water. A stock solution can be formed by mixing a fatty acid in water. The stock solution can be added to the catalyst solution to form a solid fraction and a liquid fraction. The solid fraction can be removed from the liquid fraction. The solid fraction can be washed and dried, thereby forming the functionalized metal oxide product. The functionalized metal oxide product is configured to improve the cell reversal tolerance of the fuel cell.
1 . A method for making a functionalized metal oxide product configured to be used in an anode catalyst layer of a fuel cell, comprising:
providing an aqueous catalyst solution including a metal oxide;
providing an aqueous stock solution including a fatty acid or salt thereof, wherein the fatty acid or salt thereof includes a fatty acid salt selected from a group consisting of a stearate, an oleate, and combinations thereof; and
adding the stock solution to the catalyst solution, resulting in a liquid fraction and a solid fraction, the solid fraction including the functionalized metal oxide product.
2 . The method of claim 1 , further comprising separating the solid fraction from the liquid fraction.
3 . The method of claim 2 , further comprising washing and drying the solid fraction.
4 . The method of claim 1 , wherein the metal oxide includes iridium oxide, ruthenium oxide, ruthenium iridium oxide, and composites of iridium oxide and niobium oxide, and combinations thereof.
5 . The method of claim 1 , wherein the fatty acid or salt thereof includes a sodium or a potassium fatty acid salt.
6 . The method of claim 1 , wherein the fatty acid or salt thereof includes a fatty acid salt selected from a group consisting of a stearate, an oleate, and combinations thereof.
7 . The method of claim 1 , wherein the fatty acid or salt thereof includes a fatty acid with a carbon chain of C12 to C26.
8 . The method of claim 1 , wherein the fatty acid or salt thereof includes a fatty acid with a carbon chain from C16 to C22.
9 . The method of claim 1 , further comprising a step of heating the aqueous catalyst solution.
10 . The method of claim 9 , wherein the aqueous catalyst solution is heated to between about 55° C. to about 80° C.
11 . The method of claim 1 , further comprising heating the aqueous stock solution.
12 . The method of claim 11 , wherein the aqueous stock solution is heated to between about 55° C. to about 75° C.
13 . The method of claim 1 , wherein the fatty acid or salt thereof includes sodium stearate.
14 . The method of claim 1 , wherein the functionalized metal oxide product is hydrophobic.
15 . The functionalized metal oxide product formed according to the method of claim 1 .
16 . The functionalized metal oxide product of claim 15 , further comprising about 5% to 10% sodium stearate.
17 . A membrane electrode assembly including the functionalized metal oxide product formed according to the method of claim 1 .
18 . The membrane electrode assembly of claim 17 , further comprising a platinum on carbon (Pt/C) catalyst.
19 . A fuel cell having an anode catalyst layer including the functionalized metal oxide product formed according to the method of claim 1 .
20 . The fuel cell having an anode catalyst layer of claim 19 , further comprising a platinum on carbon (Pt/C) catalyst.