Hydrothermal synthesis of 3D hierarchical MoSe2/NiSe2 composite nanowires on carbon fiber paper and their enhanced electrocatalytic activity for the hydrogen evolution reaction

A facile two-step hydrothermal approach is adopted to synthesize 3D hierarchical MoSe2/NiSe2 composite nanowires (NWs) on a carbon fiber paper (CFP) skeleton for the electro-catalytic hydrogen evolution reaction (HER) by water splitting. The MoSe2/NiSe2 NWs are composed of 2D nanosheets, and they are uniformly and tightly distributed on CFP. The electrochemical measurement suggests that only an overpotential of 249 mV (vs. the RHE) is required to deliver a current density of 100 mA cm(-2) in 0.5 M H2SO4, which is lower by 56 and 96 mV as compared to MoSe2 (305 mV) and NiSe2 (345 mV). The Tafel slope of MoSe2/NiSe2 NWs is 46.9 mV dec(-1) and is substantially smaller than those of MoSe2 (69.2 mV dec(-1)) and NiSe2 (68.8 mV dec(-1)). The MoSe2/NiSe2 composite NW arrays exhibit remarkably enhanced activity because their 3D hierarchical structure could effectively suppress the aggregation or re-stacking of nanosheets and expose more active sites to participate in the HER. Moreover, the highly conductive NiSe2 dispersed in nanosheets facilitates the transfer of electrons from the electrode to the active edges on MoSe2 and further improves the activity.