CoP nanoparticles combined with WS2 nanosheets as efficient electrocatalytic hydrogen evolution reaction catalyst

Producing hydrogen through hydrogen evolution reaction by electrolyzing water is a great alternative to solve the energy crisis and air pollution. Earth abundant transition-metal phosphides, especially CoP, have emerged as promising hydrogen evolution reaction catalysts for recent years. Nowadays, attention is focused on combining CoP with other materials to improve its catalytic activity. Herein, in order to get better hydrogen evolution reaction catalyst, we combined CoP nanoparticles with WS2 nanosheets. Different CoP to WS2 mass ratios were set to find the best catalytic activity. CoP/WS2 composites were prepared through a simple ultrasound induced mixing method. And all the CoP/WS2 composites have enhanced hydrogen evolution reaction catalytic activity than pure CoP nanoparticles and WS2 nanosheets. Especially, the optimized CoP/WS2 composite has the lowest onset overpotential of 50 mV, the largest current density of 78 mA/cm(2) at the overpotential of 300 mV, and the smallest Tafel slope of 64.63 mV/decade, indicating excellent hydrogen evolution reaction catalytic activity.