One‐step Sintering Synthesis of Ni3Se2‐Ni Electrode with Robust Interfacial Bonding for Ultra‐stable Hydrogen Evolution Reaction

Abstract Exploring efficient and robust self‐supporting hydrogen evolution reaction (HER) electrodes using simple, accessible, and low‐cost synthetic processes is crucial for the commercial application of water electrolysis at high current densities. Ni‐based self‐supporting electrodes are widely studied owing to their low cost and good catalytic performance. However, to date, the preparation of Ni‐based electrodes requires multistep and complex preparation processes. In this study, a novel one‐step in situ sintering method to synthesize mechanically stable and highly active Ni 3 Se 2 ‐Ni electrodes with well‐controlled morphologies and structures is developed. Their excellent performance and durability can be attributed to the numerous highly active nano‐Ni 3 Se 2 catalysts embedded on the surface of the Ni skeleton, the excellent conductivity of the interconnected conductive network, and the strong interfacial bonding between Ni 3 Se 2 and Ni. As a result, the Ni 3 Se 2 ‐Ni600 electrode can operate stably at 85 and 400 mA cm −2 for more than 800 and 300 h, respectively. Moreover, the Ni 3 Se 2 ‐Ni600 electrode displays outstanding stability for over 500 h in a commercial two‐electrode system. This study provides a feasible one‐step synthesis method for low‐cost, high‐efficiency metal selenide‐metal self‐supporting electrodes for water electrolysis.