NiMo@C₃N₅ heterostructures with multiple electronic transmission channels for highly efficient hydrogen evolution from alkaline electrolytes and seawater

Designing highly efficient and stable electrocatalysts for hydrogen evolution reaction (HER), particularly in seawater, still remains a challenging task. Herein, the unique heterostructures composed of 1D NiMo cores and 2D C₃N₅ shells (NiMo@C₃N₅) are rationally designed and demonstrated as the robust HER catalysts in both alkaline electrolytes and natural seawater, where the carbon-based shell can effectively protect the catalyst core from seawater poisoning. Based on the experimental investigation and density functional theory calculation, multiple electronic transmission channels were found to establish at the interface between NiMo cores and C₃N₅ shells, thus providing efficiently optimized HER pathways to achieve minimized overpotential with a reduced energy barrier of the rate-determining step. More importantly, the NiMo@C₃N₅ hybrids exhibit stable HER performance with a high Faradaic efficiency of 94.8% in seawater, which is superior to that of commercial Pt/C. All these results can evidently highlight a feasible strategy to develop high-performance HER electrocatalysts via interface engineering.