Design of hierarchical core–shell NiFeP@NMO heterostructures facilitating interfacial electron transfer and oxygen vacancy formation for efficient electrocatalytic hydrogen production

Designing low-cost and high-performance electrocatalysts to replace noble metals for the electrocatalytic hydrogen production endures a noteworthy bottleneck in an environmentally benign hydrogen generation approach. Herein, we present a hierarchical NiFeP@NiMoO 4 core–shell heterostructure (NiFeP@NMO/NF) synthesized via hydrothermal growth and electrodeposition on nickel foam, followed by phosphidation. The core–shell heterostructure optimizes active site exposure, while the heterointerface between NiFeP and NiMoO 4 facilitates rapid charge transfer and modulates electronic configurations via interfacial synergies and oxygen vacancies. The as-synthesized NiFeP@NMO/NF showed an overpotential of 41 mV for 10 mA cm −2 to actuate HER in alkaline electrolytes along with superior stability. Comprehensive characterization reveals that the core–shell structure enhances structural stability, while oxygen vacancies and interfacial electronic coupling optimize hydrogen adsorption kinetics. Density functional theory calculations reveal that NiFeP@NMO/NF superior activity from enhanced interfacial electron concentration, accelerated electron transfer, and reduced free-energy barriers for the hydrogen evolution reaction. This work underscores the pivotal role of interface engineering in designing efficient non-precious electrocatalysts, offering a viable pathway for scalable green hydrogen generation.