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/cm(2) 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. (C) 2020 Elsevier Inc. All rights reserved.