Regulative Electronic Structure of Metallic Co3Mo3N/Co Heterointerfaces in Mesoporous Carbon for Decreased Alkaline HER Energy Barriers

Hetero-interface regulation for space charge transfer is an effective strategy to achieve high-performance hydrogen evolution reaction (HER) electrocatalysis. We have constructed heterostructured Co3Mo3N/Co particles confined in porous N-doped carbon (Co3Mo3N/Co@PNC) to decrease alkaline HER energy barrier, and the synergistic mechanisms of Co3Mo3N and metal Co were identified by experiments and theoretical calculations. The heterostructure induces charge transfer from Co to Co3Mo3N at the interface, which results in increased electron density on the Co3Mo3N part, enriched and enhanced active sites, and balanced adsorption-free energy of H2O dissociation and *H intermediates. As expected, Co3Mo3N/Co@PNC showed remarkable HER activity with a low HER overpotential of only 67 mV and the extremely lower Tafel slope of 43.1 mV dec−1, which can compete with the most of recently reported catalysts. What is more, the excellent stability of Co3Mo3N/Co@PNC over 20 h was superior to Pt/C, verifying great industrial prospects to replace nobel-metal-based catalysts for efficient energy conversion.