Two-dimensional transition metal dichalcogenides (2D TMDs) have shown exceptional electrochemical catalytic activity for the efficient generation of hydrogen through electrochemical water splitting. In the case of molybdenum disulfide (MoS2), a prominent member of 2D TMDs, the electrochemically active sites primarily reside at the edges, while the basal plane, which constitutes the majority of the MoS2 structure, remains relatively inactive. In this study, we aimed to activate the inert sites of the basal plane with some defective structure for hydrogen evolution reaction (HER) by employing an electrochemical-probe in combination with voltage sweeping. The initiation of HER at these previously inactive sites was visualized and confirmed using scanning electrochemical cell microscopy (SECCM). Our findings reveal that the enhanced HER activity originates from surface defects induced by the probing process.
