Optimization of hydrogen adsorption on W2C by late transition metal doping for efficient hydrogen evolution catalysis

Abstract

Understanding the nature of hydrogen adsorption behavior and improving hydrogen desorption ability are key challenges for tungsten carbide facilitated hydrogen evolution reactions (HER). Here, late transition metal M (M = Fe, Co, and Ni) doped W2C self-supported nanorod array cathodes (M-W2C) were synthesized on carbon cloth by high-temperature carbonization of M-doped WO3. Among them, the Ni-W2C displays an excellent catalytic performance in alkaline electrolytes, which requires an overpotential of 88 mV to achieve a current density of 10 mA/cm2 and a Tafel slope of 73.8 mV/dec. The experiments combined with theoretical calculations indicate that with the late transition metal doping, the d-band center of W2C gradually moves away from the Fermi energy level, resulting in weaker hydrogen adsorption, lower interfacial transfer resistance, thus expediting the hydrogen evolution reaction process. This work demonstrates that the optimization of hydrogen adsorption by late transition metal doping is effective for the improvement of W2C catalyst activity.