Hierarchical nanowires of MoS2@transition metal sulfide heterostructures for efficient electrocatalytic hydrogen evolution reaction

Transition metal sulfides have attracted much attraction in electrochemical water splitting owing to their low cost and unlimited availability. The formation of heterostructures has been demonstrated to be an effective manner to enhance the electrocatalytic performance. In this paper, hierarchical nanowires of MoS2@transition metal sulfide (FeS, CuS, CoS2 and SnS2) heterostructures were fabricated via simple electrospinning, sulfuration and subsequent hydrothermal process. X-ray diffraction and X-ray photoelectron spectroscopy were utilized to character the crystal structures and chemical compositions of as-prepared electrocatalysts. Scanning electron microscope and transmission electron microscope characterization results confirmed the existence of heterostructures in the MoS2@transition metal sulfide hybrid nanowires. Benefitting from the synergistic effect and the increased active sites, the as-prepared MoS2@transition metal sulfide (FeS, CuS, CoS2 and SnS2) heterostructures exhibited superior electrocatalytic HER performance. The MoS2@transition metal sulfides (FeS, CuS, CoS2 and SnS2) delivered the overpotential of 52 mV, 62 mV, 88 mV and 93 mV at the current density of 10 mA/cm2, and the Tafel slope of 64 mV/dec, 82 mV/dec, 73 mV/dec and 70 mV/dec in acid media. This work provides a novel way to optimize the HER activity of nanostructured MoS2.