Electrochemical Characterization of Nano-Sized Pd-Based Catalysts as Cathode Materials in Direct Methanol Fuel Cells

To improve the catalytic activity of palladium (Pd) as a cathode catalyst in direct methanol fuel cells (DMFCs), we prepared palladium-titanium oxide (Pd–TiO₂) catalysts which the Pd and TiO₂ nanoparticles were simultaneously impregnated on carbon. We selected Pd and TiO₂ as catalytic materials because of their electrochemical stability in acid solution. The crystal structure and the loading amount of Pd and TiO₂ on carbon were characterized by X-ray diffraction (XRD) and energy dispersive X-ray microanalysis (EDX). The electrochemical characterization of Pd–TiO₂/C catalysts for the oxygen reduction reaction was carried out in half and single cell systems. The catalytic activities of the Pd–TiO₂ catalysts were strongly influenced by the TiO₂ content. In the single cell test, the Pd–TiO₂ catalysts showed very comparable performance to the Pt catalyst.