Oxygen Functionalized CoP Nanowires as High-Efficient and Stable Electrocatalyst for Oxygen Evolution Reaction and Full Water Splitting

Designing highly active, durable and cost-effective electrocatalysts for oxygen evolution reaction (OER) are very crucial for overall water splitting. The potential of cobalt phosphide (CoP) as efficient OER electrocatalyst has been emerged, but most current developed CoP-based electrocatalysts suffer from high overpotential and poor long-term stability. Herein, a new and controllable surface oxygen functionalization strategy is developed to activate CoP nanowires as high-efficient and stable OER electrocatalyst. The introduction of surface oxygen atoms can not only improve the electron transport and ion diffusion rates, but also can decreases the adsorption Gibbs free energy and prevent further structural damage, endowing the oxygen activated CoP (O-CoP) NWs with superior electrocatalytic activity and stability. The as-obtained O-CoP NW electrode achieves impressively low overpotential potentials of 265, 316 and 338 mV at the current density of 10 mA cm −2 , 50 mA cm −2 and 100 mA cm −2 , which are substantially superior to the recently reported CoP-based electrocatalysts and commercial RuO 2 . More importantly, this O-CoP NW electrode also possesses remarkable durability even after 55 h long-term test at a large current density of 50 mA cm −2 .