Oxygen reduction on a Pt70Ni30/C electrocatalyst prepared by the borohydride method in H2SO4/CH3OH solutions

The activity for the oxygen reduction reaction (ORR) on carbon supported Pt–Ni electrocatalysts prepared by reduction of Pt and Ni precursors with NaHB4 was investigated in sulphuric acid both in the absence and in the presence of methanol and compared with that of a commercial Pt/C electrocatalyst. In methanol-free sulphuric acid solution the Pt70Ni30/C alloy electrocatalyst showed a lower specific activity towards oxygen reduction compared to Pt/C. In O2-free H2SO4 the onset potential for methanol oxidation on Pt70Ni30/C was shifted to more positive potentials, which indicates a lower activity for methanol oxidation than platinum. In the methanol containing electrolyte the higher methanol tolerance of the Pt70Ni30/C electrocatalyst for the ORR was ascribed to the lower activity of the binary electrocatalyst for methanol oxidation, arising from a composition effect.