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 NaHB 4 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 Pt 70 Ni 30 /C alloy electrocatalyst showed a lower specific activity towards oxygen reduction compared to Pt/C. In O 2 -free H 2 SO 4 the onset potential for methanol oxidation on Pt 70 Ni 30 /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 Pt 70 Ni 30 /C electrocatalyst for the ORR was ascribed to the lower activity of the binary electrocatalyst for methanol oxidation, arising from a composition effect.