Mo3N2/VO2 composite as electrocatalysts for hydrogen evolution reaction

Abstract

There is a clear need to develop efficient and stable electrocatalysts for hydrogen evolution reaction (HER) that do not rely on noble metals. Transition metal nitrides are emerging as good substitutes for HER electrocatalysts because of their distinctive electronic properties and availability. Furthermore, forming suitable heterojunctions can improve their activities further. Here, a nitridation treatment, followed by a solvothermal method is used to synthesize Mo3N2/VO2 composites for obtaining outstanding HER electrocatalysts that operate in an acidic solution. The introduction of VO2 enhances the electronic conductivity and the active sites of Mo3N2/VO2. More so, the synergy between the interface of Mo3N2 and VO2 facilitates electron transfer and speeds up reaction kinetics. When investigated for HER, the best Mo3N2/VO2 catalyst displays remarkable catalytic activity with an overpotential of 166 mV and a rather small Tafel slope of 43 mV dec−1 in 0.5 M H2SO4 at a current density of 10 mA cm−2. As prepared Mo3N2/VO2 exhibits excellent stability in acidic solution over 12 h. This work opens up the possibility associated with molybdenum nitride-based electrocatalysts.