Vanadium-Doped FeNiSe₄ as a High-Performance Oxygen Evolution Electrocatalyst: Synergistic Effects of Se–Ni–Fe Hybridization and Vanadium-Induced Electronic Modulation

Hydrogen production through water electrolysis is gaining momentum as a sustainable solution for future energy systems, offering a clean and efficient pathway for energy storage and conversion. In this study, we report the synthesis of vanadium-doped iron–nickel selenide (V@FeNiSe4) as a highly active and durable electrocatalyst for the oxygen evolution reaction (OER). Prepared via a simple one-step hydrothermal method, V@FeNiSe4 demonstrates a large electrochemical surface area and accelerated OER kinetics. Comprehensive characterization employing FT-IR, powder X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, band-gap estimation, Mott–Schottky studies, electrochemical impedance spectroscopy studies, and BET analysis confirms the successful incorporation of vanadium and reveals a well-defined nanostructure. Ultraviolet photoelectron spectroscopy was utilized to study the valence band maxima and work function of FeNiSe4 and V@FeNiSe4. The remarkable OER performance is attributed to the strong synergistic effects introduced by vanadium doping, which enhance electronic conductivity, increase active site availability, and accelerate charge transfer dynamics. These findings highlight V@FeNiSe4 as a promising candidate for next-generation water-splitting technologies.