Molecular Fence Strategy Disentangles the Activity–Stability Trade-Off for Alkaline Hydrogen Evolution

MoS2-based catalysts typically confront the critical challenge of balancing high catalytic activity and stability for the hydrogen evolution reaction (HER). This issue remains largely unresolved to date, seriously hindering their practical application. Herein, we develop a feasible molecule fence strategy to address this challenge by confining highly active Ni-doped MoS2 (Ni-MoS2) within a NiS2 fence featuring molecular selectivity. The combined density functional theory (DFT) calculations and in situ spectroscopy measurements reveal that the NiS2 layer as a molecule fence not only enhances the adsorption of H2O molecules but also protects Ni-MoS2 active components from the corrosion by O2 and OH– toxic species, thus greatly inhibiting the leaching of Ni-MoS2 as well as promoting its HER activity. Furthermore, the Ni-MoS2@NiS2-assembled anion exchange membrane water electrolysis (AEMWE) device can achieve a low voltage of 1.85 V to reach a current density of 1000 mA cm–2 and maintains a long-term operation for 1000 h. This study offers insights and valuable guidance for rational construction of electrocatalysts with high activity and stability.