Electrocatalytic Activity of Nano-Crystalline Ni-Co-Mo-Fe Alloys on the Oxygen Evolution Reaction (OER)

Abstract

The electrocatalytic behavior of nanocrystalline Co 30 Ni 70 , Co 40 Mo 60 , Ni 40 Mo 60 , Co 15 Ni 30 Mo 55 , Fe 10 Co 35 Ni 55 and Co 15 Fe 30 Ni 55 mol-% alloys on the oxygen evolution reaction [OER] in a 30 wt-% KOH aqueous solution at 298, 323 and 343 K has been assessed in this work. Appreciable currents for oxygen evolution reactions were measured at Ni-Co-Mo-Fe electrodes produce by this technique. It was also found that iron increased the electrocatalytic activity for oxygen evolution reaction, but it was not as good as obtained on hydrogen evolution reaction [HER]. Tafel plots of preoxidized and prolonged cycled Co 30 Ni 70 , Co 40 Mo 60 , Ni 40 Mo 60 , Co 15 Ni 30 Mo 55 , Fe 10 Co 35 Ni 55 and Co 15 Fe 30 Ni 55 crystalline electrodes were very different, which might be related to changes in the surface enrichment of one or two of the alloy constituents. The electrocatalytic effects Mo seem to be more important on the OER at high temperatures than those showed previously for HER. Nickel and Molybdenum rich alloys showed particularly high activity towards the OER in comparison with their nanocrystalline counterparts.