Characterization and performances of cobalt-tungsten and molybdenum-tungsten carbides as anode catalyst for PEFC

The preparation of carbon-supported cobalt-tungsten and molybdenum-tungsten carbides and their activity as an anode catalyst for a polymer electrolyte fuel cell were investigated. The electrocatalytic activity for the hydrogen oxidation reaction over the catalysts was evaluated using a single-stack fuel cell and a rotating disk electrode. The characterization of the catalysts was performed by XRD, temperature-prograrmmed carburization, temperature-programmed reduction and X-ray photoelectron spectroscopy. The maximum power densities of the 30 wt% 873 K-carburized cobalt-tungsten and (CoWC)/Ketjen black (KB) molybdenum-tungsten mixed with Ketjen carbon (cobalt-tungsten carbide 2 and molybdenum-tungsten carbide (MoWC)/KB) were 15.7 and 12.0 mW cm(-2), respectively, which were 14 and 11%, compared to the in-house membrane electrode assembly (MEA) prepared from a 20 wt% Pt/C catalyst. The CoWC/KB catalyst exhibited the highest maximum power density compared to the MoWC/KB and WC/KB catalysts. The 873 K-carburized CoW/KB catalyst formed the oxycarbided and/orcarbided CoW that are responsible for the excellent hydrogen oxygen reaction. (C) 2008 Published by Elsevier Ltd.