Heterojunction regulates the function of coral like NiCoP for efficient hydrogen evolution reaction

Abstract

The development of earth abundant electrocatalysts for high performance hydrogen evolution reaction (HER) is highly desirable in energy conversion system. Transition metal phosphide has been exploited to promote electrochemical performance due to its unique heterointerface, outstanding conductivity, and a wide pH range tolerance. Herein, we employ a facile hydrothermal approach to build a heterojunction interface modulated coral-like NiCoP electrocatalyst with favorable crystalline surface, minimal charge transfer resistance, and excellent electron transfer for outstanding HER. In alkaline media, the optimum NiCoP electrocatalyst demonstrates excellent HER performance with an overpotential of 215 mV and Tafel slope of 82 mV dec−1 at 10 mA cm−2. This benefits from the formation of heterojunction with exposed active sites, redistributed electrons and altered coordination environment. The combined experimental results and density functional theory (DFT) investigations demonstrate that heterojunction interfaces are beneficial for lowering the Gibbs free energy of hydrogen adsorption (ΔGH∗), hence boosting HER dynamics process. This study presents a feasible approach for the preparation of low-cost, high-efficiency NiCoP electrocatalysts for HER, which is particularly appealing for practical applications.