High-Content Metallic 1T Phase in MoS2-Based Electrocatalyst for Efficient Hydrogen Evolution

Realizing high-efficiency hydrogen evolution in cost-effective and long-lasting electrocatalysts is critical for global production of clean and sustainable chemical fuels. Here, via modulating the metallic 1T phase in 2H MoS2 nanosheets, we greatly improved the conductivity and effective active sites for highly efficient electrocatalytic hydrogen evolution. The as-synthesized 1T-2H MoS2 electrocatalyst with a high 1T-phase content of 50% can significantly increase the charge concentration by an order of magnitude and triple the effective active surface sites, successfully boosting the hydrogen evolution reaction (HER) at a quite low overpotential of 126 mV at 10 mA/cm(2) and a small Tafel slope of 35 mV/dec. Ultraviolet photoelectron spectroscopy and electrochemical characterization reveal that the valence band edges of 1T-2H MoS2 are upshifted by 0.15-0.36 eV, which obviously enhances the charge transfer ability of the surface active sites in the basal plane of MoS2 for high HER performance.