Nano‐Nickel Pinned Defective MoS ₂ Heterostructures via Ball Milling for Improved Hydrogen Evolution

The development of cost‐effective and scalable electrocatalysts remains a key challenge for the alkaline hydrogen evolution reaction (HER). Herein, we report a simple, solvent‐free mechanochemical synthesis approach to fabricate Ni nanoparticle‐pinned, defect‐rich MoS 2 (Ni@MoS 2 ) heterojunction catalysts. This one‐step ball‐milling strategy enables simultaneous exfoliation of molybdenum disulfide (MoS 2 ) into the conductive 1T phase, generation of defects, and physical pinning of Ni nanoparticles without the need for high‐temperature or solution‐based processing. The resulting heterostructure forms a strong metal–support interaction and a Mott–Schottky interface, which facilitates water adsorption, accelerates Volmer step kinetics, and enhances the electron transfer from Ni to MoS 2 . The catalyst exhibits remarkable catalytic activity and structural robustness, requiring only 301 mV to reach 500 mA cm −2 while remaining stable at high current densities of 0.45 and 0.9 A cm −2 , owing to the defect‐reinforced pin‐type architecture. This work underscores the potential of defect and interface engineering via scalable mechanochemical methods to construct robust HER electrocatalysts for practical alkaline electrolysis.