Self-Supported NiSe2 Nanowire Arrays on Carbon Fiber Paper as Efficient and Stable Electrode for Hydrogen Evolution Reaction

NiSe2 nanowire (NW) arrays grown on flexible carbon fiber paper (CFP) were synthesized, for the first time, through a novel thermal selenization method in vacuum instead of flowing inert gas. The ultrathin NiSe2 NWs uniformly cover the CFP, contributing to the large surface area and fast charge transportation. Desirably, this binder-free and hierarchical electrode shows favorable activity for hydrogen evolution reaction (HER). It only requires an overpotential of 172 mV to afford the current density of 100 mA cm(-2) in 0.5 M H2SO4, corresponding to a low Tafel slope of 32.44 mV dec(-1). After 1000 continuous cycles, the HER activity of NiSe2 NWs is well-maintained. Moreover, the current density remains unchanged in prolonged electrolysis, indicating an excellent durability of NiSe2 NWs. The novel preparation method described in this study could inspire future work on the synthesis of transition-metal dichalcogenides with high purity and ultrasmall nanostructure toward improved electrocatalytic activity.