Au@Co2P core/shell nanoparticles as a nano-electrocatalyst for enhancing the oxygen evolution reaction

Core/shell nanoparticles (NPs) of Au@Co2P, each comprising a Au core with a Co2P shell, were prepared, and shown to efficiently catalyze the oxygen evolution reaction (OER). In particular, Au@Co2P has a small overpotential of 321 mV at 10 mA cm−2 in 1 M KOH aqueous solution at room temperature, which is about 95 mV less than pure Co2P. More importantly, the Tafel slope of Au@Co2P, at 57 mV dec−1, is 44 mV dec−1 lower than that of Co2P. Hence, Au@Co2P outperforms Co2P drastically in practical production when a high current density is required.