Ni-doped WC/Mo2C with different W/Mo ratios coating on carbon fiber paper prepared by molten salt method for efficient electrocatalytic hydrogen evolution

Ni-doped WC/Mo2C composites for hydrogen evolution reaction (HER) were synthesized in situ grown on carbon fiber paper (CFP) by molten salt method in argon at 1000 degrees C for 6 h, named as Ni-xWC-y/2Mo2C@CFP. The effects of different W/Mo molar ratios (3:1, 2:1, 1:1, 1:2, 1:3) on the phase composition, microstructures, and HER performances were investigated. The results showed that the W/Mo molar ratio had a synergistic effect in HER of Ni-doped WC/Mo2C composites, and as W/Mo molar ratio at 1:1, the composite presented the best electrocatalytic activity. Meanwhile, its surface appeared to have a wrinkle-like structure, and the biphasic heterostructure emerged at the intersection of the dual-phase WC and Mo2C lattices. The introduction of a biphasic heterostructure could promote charge transfer and improve HER efficiency. Predictably, the electrocatalysts with the optimal W/Mo molar ratio 1:1 exhibited the best hydrogen evolution performance, needed only 43.7 mV overpotential to reach 10 mA cm-2 current density with a Tafel slope at 21.3 mV dec-1. In this work, the high-efficiency electrocatalysts of Ni-doped 1WC-1/2Mo2C@CFP have been prepared, which provides an insight into theoretical research of composite carbon-based electrocatalysts.