Formation of cobalt phosphide nanodisks as a bifunctional electrocatalyst for enhanced water splitting†
Exploring efficient and cheap electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is crucial for water splitting. Herein, novel porous disk-like nanostructured CoP (CoP NDs) were synthesized by a facile strategy involving precipitation, ammonia-etching and phosphidation steps. Endowed with abundant catalytically active sites and enriched nanoporosity, the CoP NDs show excellent bifunctional catalytic performances toward both HER and OER, which are comparable and even superior to those of the recently reported noble-metal-free electrocatalysts. Consequently, an efficent water electrolyzer composed of two symmetrical CoP ND electrodes can afford a current density of 10 mA cm−2 at a cell voltage of 1.62 V.