Two-dimensional ultrathin arrays of CoP: Electronic modulation toward high performance overall water splitting

Transition metal phosphides (TMPs) have shown promising performance in electrocatalytic water splitting. However, the sluggish kinetic of oxygen evolution reaction (OER) process deteriorates their activity toward overall water splitting. To overcome this issue, two-dimensional (2D) ultrathin arrays of metal-doped CoP (MCoP; M = Fe, Ni, and Mg) were successfully prepared by using layered double hydroxides (LDHs) as precursors. The as-obtained 2D ultrathin arrays exhibit an outstanding electrocatalytic activity and long-term durability toward both half-reaction in overall water splitting. As a result, the electrolyzer assembled by FeCoP UNSAs consumes a cell potential as low as 1.60 V (at 10 mA cm(-2)). An experimental-theoretical combination study reveals that the electronic structure of Co is modulated via the incorporation of Fe, which benefits the adsorption of water molecule and the dissociation of OH group, accounting for the largely enhanced activity toward overall water splitting.