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

MoS 2 -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 MoS 2 (Ni-MoS 2 ) within a NiS 2 fence featuring molecular selectivity. The combined density functional theory (DFT) calculations and in situ spectroscopy measurements reveal that the NiS 2 layer as a molecule fence not only enhances the adsorption of H 2 O molecules but also protects Ni-MoS 2 active components from the corrosion by O 2 and OH – toxic species, thus greatly inhibiting the leaching of Ni-MoS 2 as well as promoting its HER activity. Furthermore, the Ni-MoS 2 @NiS 2 -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.