Tunable Ni/Fe‐Mo carbide catalyst with high activity toward hydrogen evolution reaction

Abstract

AbstractCost‐effective catalysts for hydrogen evolution reaction (HER) are attractive for sustainable production of H2 fuel. Herein, a series of tunable Ni/Fe‐Mo carbide catalysts have been synthesized via a sol‐gel method coupling with a subsequent high temperature carbonization process. The amount of nickel and iron was tuned in the Mo7/C precursors, accomplishing a favourable performance of noble‐metal‐free electrocatalysts for HER. As expected, the designed Ni10Fe4Mo7/C catalyst displays an enhanced catalytic activity toward hydrogen production with an ultralow overpotential (η10 = 110 mV) and striking kinetics (ηonset = 58 mV, k = 54 mV · dec−1) in the alkaline electrolyte (1 M KOH), which are comparable to those of the commercial 20% Pt/C catalyst. Such excellent performance of Ni10Fe4Mo7/C could be attributed to the high intrinsic activities of Ni‐based alloys (NiMo4) and Mo2C, as well as to the lattice contraction in the Mo2C unit cell, in accordance with its high electrochemical surface area (~133 m2 · g−1) and low charge‐transfer resistance (~31.5 Ω) for the associated electrode.