IMPROVED ELECTROCATALYTIC OXYGEN REDUCTION PERFORMANCE OF PLATINUM TERNARY ALLOY-OXIDE IN SOLID-POLYMER-ELECTROLYTE FUEL-CELLS

The effect of base metal oxide (nonnoble metal oxide) in a Pt-Cr-Cu al loy catalyst is investigated for the oxygen reduction reaction in a so lid-polymer-electrolyte fuel cell. The cathode mass activities ai 0.9 V for Pt, Pt-Cr alloy, Pt-Cr-Cu alloy, and a mixture of Pt-Cr-Cu alloy with base metal oxide are compared. The enhancement factor is largest (about 6 times) for the mixture of Pt-Cr-Cu alloy with base metal oxi de, compared to Pt-Cr and Pt-Cr-Cu alloys (about 2 times). The higher electrocatalytics activity of this material may be due to the combined effects of the Pt-Cr-Cu alloy and the base metal oxide. The physical and electrochemical characterizations are carried out using various te chniques like x-ray diffraction, transmission electron microscopy, cyc lic voltammetry, polarization, and ac impedance.