Coupled Regulation of Interfacial Water Dynamics and Electronic Structure in Fe–MoP Nanocrystals for Hydrogen Evolution

The hydrogen evolution reaction (HER) suffers from sluggish interfacial kinetics, particularly in alkaline media, where rigid hydrogen-bonded water clusters impede O–H cleavage and proton transfer. A molecularly coupled interface construction (MCIC) strategy was employed to confine Fe–MoP nanocrystals within a nitrogen-doped carbon matrix, creating robust heterointerfaces. Fe incorporation reconstructs the electronic structure, producing Fe–Mo dual sites with complementary d-band centers, and reorganizes interfacial water by destabilizing tetrahedral clusters and enriching weakly bound species. In situ Raman spectroscopy, impedance analysis, and density functional theory confirmed this dual regulation. The catalyst achieves overpotentials of 108 and 128 mV at 10 mA cm–2 in alkaline and acidic electrolytes, respectively, with stable operation for over 150 h. These results define an integrated mechanism linking electronic reconstruction and interfacial water reorganization, guiding the design of efficient nonprecious HER electrocatalysts.