Nickel-rare earth (RE = Ce, Sm, Dy) electrodes for H<inf>2</inf>O<inf>2</inf> reduction in fuel cells

Abstract

The use of hydrogen peroxide (H2O2) as an oxidant is considered a good alternative to oxygen for the cathodic process in liquid fuel cells. Herein, we studied the reduction of H2O2 at nickel and at nickel-rare earth (RE = Ce, Sm, Dy) alloys containing 5 and 10 at.% of RE metal. The alloys were prepared by arc melting, starting from the stoichiometric amounts of the two parent metals, and analyzed by X-ray diffraction and scanning electron microscopy coupled with energy-dispersive spectroscopy. The electrochemical characterization was carried out by voltammetry and chronoamperometry measurements in alkaline media, in which main parameters were calculated, namely diffusion coefficients and number of exchanged electrons. Ni0.95Ce0.05 alloy exhibited the highest catalytic activity for H2O2 reduction reaction, with a number of exchanged electrons of 1.7. Additionally, activation energies were estimated according to Arrhenius equation.