Self-supporting Ni-doped Mo2C@CFP electrode prepared by molten salt method for Hydrogen Evolution Reaction

Abstract:

Mo₂C possesses the electronic structure and catalytic properties similar to that of Pt-like noble metals, thus been suggested to be an encouraging non-noble metal electrocatalysts substitute to the noble metals. However, pure Mo₂C has poor conductivity and slow hydrogen release kinetics. In order to improve the electrocatalytic hydrogen evolution performance of Mo₂C, this work employed a low-temperature molten salt method to prepare several self-supporting Mo₂C electrocatalysts on carbon fiber paper (CFP). The effects of molybdenum sources (Mo, MoO₃), nickel sources (Ni, Ni(NO₃)₂) and carbon black on the phase, microstructure/morphology and electrocatalytic performance of the synthesized product were investigated. The results show that the introduction of carbon black and Ni can promote the refinement of Mo₂C grains and the formation of wrinkled structure on its surface, thus providing more active sites. When using MoO₃ as molybdenum source, Ni(NO₃)₂ makes the morphology of Mo₂C transforming from granular to flower-like, which greatly increases its specific surface area, and also promotes the electron transfer efficiency in the synthesized Ni(NO₃)₂-Mo₂C_CBO@CFP composite electrode. This composite electrode shows the best HER activity, with the smallestη₁₀ of 117 mV and the lowest Tafel slop of 73.8 mV dec^_-1.

Key words:molten salt method synthesis; molybdenum carbide; electrocatalytic performance; self-supporting electrocatalyst; Ni doping