Heterointerface and Defect Dual Engineering in a Superhydrophilic Ni2P/WO2.83 Microsphere for Boosting Alkaline Hydrogen Evolution Reaction at High Current Density

Developing a high-performance electrocatalyst for hydrogen evolution reaction (HER) requires a comprehensive consideration of the three key factors, that is, intrinsic activity, electric conductivity, and active site number. Herein, we report the facile synthesis of a self-supported Ni2P/WO2.83 heterointerface microsphere as a highly active and low-cost catalyst for alkaline HER, which has simultaneously addressed these key issues by a joint application of heterointerface construction and defect and architecture engineering strategies. Our density functional theory calculations revealed Ni2P and WO2.83 optimized by the interface coupling effect work in concert to improve the intrinsic activity of the catalyst. Importantly, the metalloid Ni2P in an intimate combination with the oxygen-defect-rich WO2.83 species endowed the electrocatalyst with high conductivity. Furthermore, the Ni2P/WO2.83 electrocatalyst presented a superhydrophilic nanostructure, ensuring abundant active sites and their accessibility. Benefiting from these attributes, the obtained Ni2P/WO2.83 heterointerface electrocatalyst exhibited excellent activity along with favorable stability for alkaline HER, especially at high current density, surpassing the most reported non-precious catalysts.