Engineering sulfur vacancies in basal plane of MoS₂ for enhanced hydrogen evolution reaction

Engineering sulfur vacancies in the basal plane of MoS₂ is an effective method to enhance its catalytic activity. However, the traditional methods are only effective for multilayer or monolayer MoS₂ supported on the substrate (such as Si/SiO wafer or carbon paper), which are not applied in bulk or commercial MoS₂. In this work, we developed a simple and general chemical reduction method for engineering S-vacancies in the MoS₂ basal plane and additional active edge sites, which can be exploited to improve the HER catalytic performance of MoS₂. The optimized MoS₂ nanosheets with S-vacancies exhibit excellent HER activity with a small overpotential of 190 mV at large density of 10 mA/cm² and a low Tafel slope of 54 mV decade⁻¹. Moreover, prominent electrochemical durability was also achieved. This finding proposes an effective strategy to fabricating S-vacancies for activating basal plane of 2D transition metal chalcogenides materials.