Carbon supported Pt–Pd alloy as an ethanol tolerant oxygen reduction electrocatalyst for direct ethanol fuel cells

A carbon supported Pt–Pd catalyst with a Pt:Pd atomic ratio 77:23 was prepared by reduction of metal precursors with formic acid and characterized by EDX, XRD and XPS techniques. A decrease of the lattice parameter compared with that of pure Pt was observed, indicating the formation of a Pt–Pd alloy. Tests in H2SO4 solution in the absence of ethanol showed that the Pd-containing is slightly more active than pure Pt for the oxygen reduction reaction (ORR). In the presence of ethanol a larger increase in overpotential of the ORR on pure Pt than that on Pt–Pd was found, indicating a higher ethanol tolerance of the binary catalyst. The enhanced performance at 90 °C of the direct ethanol fuel cell with Pt–Pd/C as cathode material confirmed the results of half cell tests, and was essentially ascribed to a reduced ethanol adsorption on Pt–Pd.