Heterointerface and Defect Dual Engineering in a Superhydrophilic Ni 2 P/WO 2.83 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 Ni 2 P/WO 2.83 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 Ni 2 P and WO 2.83 optimized by the interface coupling effect work in concert to improve the intrinsic activity of the catalyst. Importantly, the metalloid Ni 2 P in an intimate combination with the oxygen-defect-rich WO 2.83 species endowed the electrocatalyst with high conductivity. Furthermore, the Ni 2 P/WO 2.83 electrocatalyst presented a superhydrophilic nanostructure, ensuring abundant active sites and their accessibility. Benefiting from these attributes, the obtained Ni 2 P/WO 2.83 heterointerface electrocatalyst exhibited excellent activity along with favorable stability for alkaline HER, especially at high current density, surpassing the most reported non-precious catalysts.