Ultrafast preparation of ruthenium nanoparticle/molybdenum oxide/nitrogen-doped carbon nanocomposites by magnetic induction heating for efficient hydrogen evolution reaction

Abstract

Ruthenium has emerged as a viable electrocatalyst towards hydrogen evolution reaction (HER) in alkaline media, where the performance can be further enhanced by slight weakening of H adsorption. Herein, nanocomposites with ruthenium nanoparticles dispersed on molybdenum oxide supported on nitrogen-doped carbon are synthesized via ultrafast magnetic induction heating at controlled currents for only 10 s, and exhibit evident HER activity in 1 M KOH. Among the series, the RuMoO_x/NC-5 sample, with a Ru : Mo atomic ratio of ca. 3 : 1, shows the best performance, featuring a low overpotential of only −39 mV to reach the current density of 10 mA cm⁻² and a low Tafel slope of 28.3 mV dec⁻¹, which is markedly better than those of the monometal counterparts, samples with a lower Ru : Mo ratio, and even commercial 20 wt% Pt/C. This is attributed to weakened H adsorption on Ru active sites by the synergetic interactions between ruthenium and molybdenum oxide, as confirmed in theoretical studies based on density functional theory calculations.