Skutterudite-Type Ternary Co_{1- x}Ni_xP₃ Nanoneedle Array Electrocatalysts for Enhanced Hydrogen and Oxygen Evolution

Developing earth-abundant and low-cost electrocatalysts for water splitting is important for the conversion systems of renewable and clean energy. Herein, under the guidance of theoretical calculations, a new type of skutterudite-type ternary cobalt nickel phosphide (Co_1-xNi_xP₃) nanoneedle arrays (NAs) is fabricated on carbon cloth for the splitting of water. The electronic structure was tuned by doping an appropriate amount of Ni, and the resultant Co_0.93Ni_0.07P₃ displayed good catalytic activity toward hydrogen evolution reaction (HER) with an overpotential (η₁₀) of 87 mV versus reversible hydrogen electrode (RHE) when the current density reaches -10 mA cm^-2 and the Tafel slope of the catalyst is 60.7 mV dec^-1 in alkaline electrolyte. In addition, the Co_0.93Ni_0.07P₃ also exhibited an OER activity (η₂₀ of 221 mV vs RHE and the Tafel slope of 83.7 mV dec^-1). These skutterudite-based Co_1-xNi_xP₃ electrocatalysts show promising potential in the applications of overall water splitting in an alkaline environment.