Carbon Nanotube with Vertical 2D Molybdenum Sulphoselenide Nanosheet Arrays for Boosting Electrocatalytic Hydrogen Evolution

Transition metal dichalcogenides (TMDs) are a promising non-noble-metal electrocatalyst toward the hydrogen evolution reaction (HER). However, the sluggish HER kinetics and poor electric conductivities of the TMDs severely restrict their practical applications for high-efficient water splitting. Herein, a nanosheet array of 2D anion-tailored MoSexS2-x on carbon nanotubes (CNTs) was prepared through an anionic substitution reaction. The all-solid-state sulfidation of the CNT-MoSe2 precursor using the sulfur powder as the sulfur source indicates a green and easily scalable strategy for the preparation of the CNT-MoSexS2-x hybrid. As a result, the CNT-MoSexS2-x hybrid delivers an excellent HER performance including a low onset overpotential (83 mV), small Tafel slope (40 mV dec(-1)) and long-term stability (overpotential at 10 mA cm(-2) from 160 to 166 mV after 6000 cycles). The superior electrocatalytic activities of the CNT-MoSexS2-x hybrid are originated from decreased hydrogen adsorption energy associated with altering arrangements of Se and S atoms within the MoSexS2-x nanosheets. In addition, the MoSexS2-x nanosheet array on the highly conductive backbones of CNTs also enables an efficient electron/ion transport thus manifesting fast HER kinetics.