Potential‐Programmed Mo Dissolution–Induced Reconstruction of Commercial NiMo Foam for High‐Current Alkaline Hydrogen Evolution

ABSTRACT Hydrogen production via water electrolysis is a sustainable pathway, yet its widespread application is hindered by high energy consumption. Therefore, the development of efficient non‐precious‐metal catalysts for the hydrogen evolution reaction (HER) is of great importance. NiMo alloys exhibit outstanding HER activity in alkaline media; however, the role of Mo dissolution during operation remains poorly understood. Here, the anodic reconstruction potential is used as an external programming variable to regulate Mo dissolution and surface oxidation in commercial NiMo foam, generating under‐reconstructed, optimally reconstructed, and over‐leached surface states within a tunable reconstruction window. The optimized reconstructed surface lowers the water‐dissociation energy cost while maintaining an optimized hydrogen binding energy, thereby facilitating the Volmer step and accelerating HER kinetics. Together, electrochemical perturbation/control experiments, CV, spectroscopy, and DFT calculations support Ni‐derived sites as the predominant H‐binding/evolution centers, while residual Mo regulates their electronic and interfacial environment. In alkaline water electrolysis, the reconstructed electrode delivers 1 A cm −2 at 1.76 V in 6 m KOH at 90°C and sustains operation at 4 A cm −2 for over 1800 h at 80°C. These results establish potential‐programmed reconstruction as a practical strategy for rationally regulating reconstruction chemistry and designing efficient catalysts for high‐current‐density alkaline electrolysis.