Construction of an Iron-Modulated NVS Hydrangea-like Structure with Rich Heterogeneous Interfaces for Efficient Oxygen Evolution Reaction

The pursuit of sustainable oxygen evolution reaction (OER) technologies has positioned the rational design of high-efficiency earth-abundant electrocatalysts as a critical frontier in realizing hydrogen economy objectives. Among candidate materials, transition metal sulfides exhibit remarkable OER catalytic capabilities, where strategic modifications, including morphological engineering, heteroatom doping, and interfacial optimization, have been extensively employed to augment their activity. In this context, we demonstrate a hydrangea-like Fe–Ni3S2/VS heterostructure engineered with an optimized electronic configuration. This architecture integrates multiple advantageous characteristics: an expanded electrochemically active surface area of 51.2 cm2, reduced charge-transfer resistance (Rct), improved electrical conductivity, and numerous accessible catalytic sites, collectively enabling superior reaction kinetics. The optimized catalyst achieves an ultralow overpotential of 274 mV at 10 mA cm–2 current density accompanied by a favorable Tafel slope of 37.12 mV dec–1 in alkaline electrolyte while maintaining exceptional operational stability during extended OER testing. Overall, this study establishes a viable paradigm for developing biphase metal chalcogenide electrocatalysts, providing critical insights into the design of non-noble metal-based catalytic systems for scalable green hydrogen production.