Electric Field-Driven Interfacial Alloying for in Situ Fabrication of Nano-Mo2C on Carbon Fabric as Cathode toward Efficient Hydrogen Generation.

A binderless composite cathode for efficient electrocatalytic hydrogen evolution reaction (HER), Mo2C-decorated carbon cloth (denoted as CC/MC), is simply fabricated via a novel and unique strategy which involves a solid-solid phase interfacial electrochemical reaction between carbon fiber and bulk-MoS2 in molten NaCl-KCl (700 °C). MoS2, evenly coated on carbon cloth (CC), is electrochemically reduced in situ and readily reacts with the carbon fibers of CC current collector to form a Mo2C nanoparticle layer. The experiment and calculation results show that the applied electric field results in a declining migration barrier of Mo vacancies in Mo2C lattice, which promotes the diffusion of Mo atoms into carbon across the interfacial Mo2C layer, thereby impelling the combination of Mo with C in depth. The electrochemical tests indicate that the optimized cathode (CC/MC-2) exhibits a small overpotential of 134.4 mV at 10 mA cm-2 and stays stable for HER in acidic media. The catalytic capacity for N2 reduction of CC/MC-2 is analyzed. In addition, a Ni-doped Mo2C-modified carbon fabric electrode with enhanced HER activity (η10 = 96.6 mV) can be prepared through a similar process.