Constructing Reactive Micro-Environment in Basal Plane of MoS 2 for pH-Universal Hydrogen Evolution Catalysis.

MoS 2 represents a promising catalyst for the hydrogen evolution reaction (HER) in water splitting, but the inefficient catalytic activity in a pH-universal environment is an obstacle to developing practical applications. Boosting and balancing the water dissociation and hydrogen desorption kinetics is crucial in designing high-performance catalysts for the overall pH range. Herein, it is experimentally demonstrated that cobalt single-atom doping can effectively construct a reactive CoMoS micro-environment on the basal plane of MoS 2 and thus alter the uniformity of surface electron density, which is further confirmed by the theoretical results. The reactive micro-environment consisting of single-atom Co with the surrounding Mo and S atoms possesses excellent water dissociation and hydrogen desorption kinetics, exhibiting a superior performance of 36 mV at 10 mA cm -2 with a Tafel slope of 33 mV dec -1 in the alkaline condition. Meanwhile, it also shows worthy activity in the acidic (97 mV) and neutral (117 mV) environments. This work provides a facile strategy to improve the HER catalysis of MoS 2 in pH-universal environments.