Deep Phase Transition of MoS2 for Excellent Hydrogen Evolution Reaction by a Facile C-Doping Strategy

Metallic 1T-phase MoS2 is considered to be the ideal electrocatalyst to carry out hydrogen evolution reaction (HER) because of favorable conductivity and sufficient active site compared with 2H-phase MoS2. Nevertheless, 1T-phase MoS2 is conventionally synthesized in a complicated process, with the production of an unstable product, which hinders their practical applications. Herein, we propose a facile approach through a carbon-doping-induced phase transition to obtain highly stable 1T-2H mixed MoS2 nanosheets. The phase transition process is characterized by Raman and X-ray photoelectron spectroscopy, as well as high-resolution transmission electron microscopy images and delivers a high phase purity of similar to 60% for 1T-MoS2. According to density functional theory simulations and experimental results, C-doped 1T-2H mixed MoS2 has the advantages of abundant active sites, facilitated charge transfer rate, and high activity toward HER. The obtained C-doped MoS2 exhibits a superb HER electrocatalytic performance, with a current density of 10 mA cm(-2) and the overpotential as low as 40 mV in 1 M KOH solution, and brilliant stability.