MoOC-Mo2C/C heterojunction enables fast water dissociation for efficient alkaline hydrogen evolution reaction

The advancement of non-precious electrocatalysts with high efficiency is crucial for the industrial implementation of the hydrogen evolution reaction (HER). In non-acidic environments, the dissociation of water and interactions between hydrogen and the catalyst are pivotal. This research presents a novel hybrid electrocatalyst, comprising a molybdenum oxycarbide and carbide heterojunction integrated onto carbon cloth (MoOC-Mo 2 C/C), which is fabricated through in situ interface engineering. The MoOC-Mo 2 C catalyst demonstrates exceptional electrical conductivity and remarkable HER performance across a wide pH range, particularly in alkaline conditions, as exemplified by Tafel slope of 38 mV dec − 1 , an ultralow overpotential of 45 mV at a current density of 10 mA cm −2 , and notable long-term stability. Both experimental findings and theoretical analyses suggest that the incorporation of oxygen into the carbide structure enhances water adsorption and lowers the energy barrier for water dissociation. Furthermore, the distinct work functions of MoOC and Mo 2 C facilitate effective electron transfer from MoOC to Mo 2 C, optimizing the energy of hydrogen adsorption and significantly enhancing the activity and kinetics of alkaline HER. Our results underscore the promising potential of this highly efficient non-precious electrocatalyst, which exhibits a pronounced affinity for water molecules, in facilitating hydrogen evolution in alkaline media . • MoOC-Mo 2 C heterojunction is formed by thermal reduction of carbon-intercalate MoO x . • Oxygen incorporation boosts water adsorption and dissociation at MoOC-Mo 2 C interface. • The MoOC-Mo 2 C heterojunction exhibits strong electron coupling effects. • The MoOC-Mo 2 C catalyst shows excellent HER activity in alkaline and seawater.