On the suitability of hydrous ruthenium oxide supports to enhance intrinsic proton conductivity in DMFC anodes

Hydrous ruthenium oxides have been investigated as novel support materials for fuel cell electrocatalysts for use in DMFC applications. These oxides were chosen in particular due to their potential intrinsic proton conductivity. Pt nanoparticles have been deposited onto the new support, and the resulting catalysts characterized both structurally and electrochemically. The Pt nanoparticles are sized between 3-4 nm and are highly dispersed on the support. Transmission electron micrographs show that the individual Pt nanoparticles are covered by an amorphous coating layer - probably hydrous ruthenium oxide, in good agreement with the XPS data. Electrochemical measurements on model electrodes indicate that proton conductivity of the supporting material is strongly affected by interdiffusion of methanol. Nevertheless, initial tests on membrane electrode assemblies (MEAs) showed improved performance, particularly with respect to internal resistance, when compared to Pt-Ru black. The catalyst showed very high activity in CO stripping experiments performed on a full MEA, suggesting high catalyst utilization, despite the comparatively low Nafion® content used in the electrode layer.