Ex situ evaluation of tungsten oxide as a catalyst support for PEMFCs

The oxidation of carbon catalyst supports causes acute degradation in catalyst performance in proton exchange membrane fuel cells (PEMFCs). Tungsten oxide is considered here as a candidate material as an alternative catalyst support. A new method has been developed that allows Pt deposition on tungsten oxide catalyst supports. The electrochemical stability of tungsten oxide was studied by applying a coating of a tungsten-oxide-supported Pt catalyst to a rotating disk electrode and to a gold mesh. Accelerated oxidation tests were performed in deoxygenated 0.5 M H2SO4 at 30 and 80 degrees C. The oxidation stability of Pt/tungsten oxide and of Hispec 4000, a commercial catalyst, each coated on a gold mesh, was measured at 80 degrees C. The oxygen reduction reaction (ORR) activity of Pt/tungsten oxide remained high, even after accelerated oxidation tests, while the ORR activity was extremely poor after accelerated oxidation tests of Hispec 4000. (c) 2007 The Electrochemical Society.