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