Facile and Scalable Mechanochemical Synthesis of Defective MoS₂ with Ru Single Atoms Toward High-Current-Density Hydrogen Evolution

Designing a facile strategy to prepare catalysts with highly active sites are challenging for large-scale implementation of electrochemical hydrogen production. Herein, a straightforward and eco-friendly method by high-energy mechanochemical ball milling for mass production of atomic Ru dispersive in defective MoS₂ catalysts (Ru₁@D-MoS₂) is developed. It is found that single atomic Ru doping induces the generation of S vacancies, which can break the electronic neutrality around Ru atoms, leading to an asymmetrical distribution of electrons. It is also demonstrated that the Ru₁@D-MoS₂ exhibits superb alkaline hydrogen evolution enhancement, possibly attributing to this electronic asymmetry. The overpotential required to deliver a current density of 10 mA cm⁻² is as low as 107 mV, which is much lower than that of commercial MoS₂ (C-MoS₂, 364 mV). Further density functional theory (DFT) calculations also support that the vacancy-coupled single Ru enables much higher electronic distribution asymmetry degree, which could regulate the adsorption energy of intermediates, favoring the water dissociation and the adsorption/desorption of H*. Besides, the long-term stability test under 500 mA cm⁻² further confirms the robust performance of Ru₁@D-MoS₂. Our strategy provides a promising and practical way towards large-scale preparation of advanced HER catalysts for commercial applications.