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Electrochemical and Solid State Letters, Vol.10, No.12, B210-B213, 2007
Platinum-glass composite electrode for fuel cell applications
Thin-film electrodes for a low-power direct methanol fuel cell (DMFC) were prepared by incorporating carbon-supported Pt nanoparticles (Pt/C) into a silicon dioxide glass matrix. The SiO2 matrix was prepared via a sol-gel technique where tetraethyl orthosilicate (TEOS) was hydrolyzed by H2O in the presence of methanol. The Pt/C was stirred into the sol and the resulting mixture was applied to a glass membrane substrate and cured. The resulting films were similar to 2 mu m thick. Scanning electron microscopy (SEM) images indicate that the Pt/C was well dispersed, forming glass-separated conductive islands with sheet resistances in excess of 5000 Omega/square. The catalyst islands were interconnected into a conductive sheet by electrolessly depositing platinum from an aqueous plating bath. The Pt/C-SiO2 glass composite thin-film electrodes showed high methanol oxidation peak currents of similar to 180 mA/cm(2) when immersed in 0.5 M H2SO4, 0.5 M methanol electrolyte. The composite electrode was also applied to the anode of a 1 cm(2) passive DMFC and compared to an equivalent passive DMFC with a traditional Nafion-based Pt anode electrode with 10 M MeOH at room temperature. The composite electrode DMFC showed a 50 mV higher open-circuit voltage than the Nafion electrode cell, and the current density was also modestly improved. (c) 2007 The Electrochemical Society.