Nickel Nanowire Oxidation and Its Effect on Platinum Galvanic Displacement and Methanol Oxidation

Abstract

The heat treatment of nickel (Ni) nanowires (NiNWs) in oxygen is examined for its effect on platinum (Pt) galvanic displacement and the activity of Pt-coated NiNWs (PtNiNWs) in the methanol oxidation reaction (MOR). Annealing of NiNWs in oxygen is found to reduce Pt displacement and increase the resistance of surface Ni to potential-driven dissolution (during electrochemical break-in). By reducing Ni dissolution, oxophilic species are provided in close proximity to Pt sites and the MOR activity of PtNiNWs improves, particularly at low overpotential in rotating disk electrode half-cells.