p‐Block Aluminum Tailoring Termination‐Acidity of Two‐Dimensional MoS 2 Nanosheets for Alkaline Hydrogen Evolution Reaction

Molybdenum disulfide (MoS 2 ) has shown promising electrocatalytic hydrogen evolution reaction (HER) activity in acidic electrolyte, while its high‐pH alkaline HER performance is critically poor due to the sluggish water dissociation kinetics. Herein, utilizing local oxygen coordination brought by p‐block aluminum (Al 3+ ) cations, we report a termination‐acidity tailoring strategy to optimize the surface chemistry of MoS 2 catalyst to construct an acid‐like interface. Accordingly, the well‐designed AlO x ‐MoS 2 catalyst exhibits a considerable HER activity in 1.0 m KOH, achieving a low overpotential of 98 mV at 10 mA/cm 2 (η 10 ) with a small Tafel slope value (75 mV/dec). In contrast, an inferior HER activity (η 10 = 545 mV, Tafel slope = 130 mV/dec) is observed in bare oxygen modified MoS 2 (O‐MoS 2 ) counterpart. Moreover, the AlO x ‐MoS 2 catalyst displays an exceptional electrochemical stability, continuous hydrogen generation over 150 h without significant activity loss. Multiple spectroscopy characterizations and theory simulation demonstrate that the introduction of AlO x groups into in‐plane MoS 2 surface enriches protons at solid‐liquid interface, accelerating proton recombination. Additionally, the strong coordination ability of Al 3+ stabilizes the local acid‐like environment via ‐Al‐OH‐Mo‐ motifs. Our work may provide a simple but feasible surface‐chemistry modification strategy to fully trigger the intrinsic alkaline HER activity of MoS 2 itself.