Platinum-Coated Cobalt Nanowires as Oxygen Reduction Reaction Electrocatalysts

Cobalt nanowires (CoNWs) are coated with platinum (Pt) by partial galvanic displacement, forming core/shell wires 200–300 nm in diameter and 100–200 μm in length. Pt-coated CoNWs (PtCoNWs) are characterized for activity in the oxygen reduction reaction (ORR) with rotating disk electrode half-cells in 0.1 M perchloric acid electrolytes. The resulting catalysts demonstrate ORR-specific activities in the range 2053–2783 μA cm Pt −2, comparable to the specific activity of polycrystalline Pt. The specific activities of PtCoNWs increase with decreasing Pt content and exhibit a corresponding increase in Pt lattice compression. PtCoNWs have exhibited a maximum mass activity of 793 mA mg Pt −1, 2.6 times greater than carbon-supported Pt nanoparticles.