A novel composite of network-like tungsten phosphide nanostructures grown on carbon fibers with enhanced electrocatalytic hydrogen evolution efficiency

Abstract Enhancing the electrocatalytic activity of transition metal phosphides (TMPs) for hydrogen evolution has become an attractive way for noble-metal-free electrocatalysts. In this work, a novel composite of network-like tungsten phosphide nanostructures on carbon fibers (CFs@WP) was prepared by a two-step high-temperature calcination strategy. Owing to the high electrochemical active surface area originating from the WP nanostructures of network-like morphology and the enhanced conductivity caused by the introduction of carbon fibers, the obtained CFs@WP composite, as an integrated hydrogen evolution cathode, exhibits much higher electrocatalytic activity for hydrogen evolution than pure WP nano-/micro-particles after toasting their corresponding suspension onto bare CFs. This catalyst could, in 0.5 mol·L −1 H 2 SO 4 , deliver a current density of 10 and 100 mA·cm −2 respectively at the over-potential of merely 137 mV and 215 mV, and present a small Tafel slope of 69 mV·dec −1 as well as excellent stability at various current densities, although it may exhibit relatively inferior catalytic activity in hydrogen evolution in neutral and alkaline conditions. The present strategy may also offer a straight-forward model to enhance the hydrogen evolution activity of other TMPs catalysts.