Indexed on: 01 Nov '92Published on: 01 Nov '92Published in: Journal of Applied Electrochemistry
Powder catalysts were prepared by immersion of amorphous Ni-40Zr and Ni-40Ti alloys containing a few at % of platinum group elements in HF solution. This treatment led to preferential dissolution of the valve metal and nickel with a consequent formation of microcrystalline alloy powders consisting of concentrated platinum group elements and some nickel and valve metal. Porous gas-diffusion electrodes prepared by using these alloy catalyst powders were employed for electrochemical reduction of oxygen and oxidation of hydrogen in 1 M H2SO4 at 25°C. The activity of the electrodes prepared from the amorphous alloys containing Pt−Ru, Pt−Rh, Pt and Pd for oxygen reduction was considerably higher than that of the platinum black electrode. Oxidation of hydrogen occurred readily close to the equilibrium potential. Amorphous alloy electrodes containing Pt−Ru, Pt−Rh and Pt were more active than the platinum black electrode for the hydrogen oxidation.