One-step Sintering Synthesis of Ni 3 Se 2 -Ni Electrode with Robust Interfacial Bonding for Ultra-stable Hydrogen Evolution Reaction.

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.