Interface-driven charge transport modulation in α-Fe2O3/Ni3S2 heterostructures for efficient overall water splitting

Abstract

Designing advanced electrocatalysts is crucial for the sustainable and efficient generation of hydrogen through electrochemical water splitting. In this research, a novel heterostructure consisting of Ni3S2 nanoneedles intricately interwoven with α-Fe2O3 nanosheets (α-Fe/Ni3S2) was synthesized using a facile liquid-phase sol-gel method. The engineered architecture provides abundant α-Fe2O3/Ni3S2 heterointerfaces, enabling pronounced electronic interaction and synergistic coupling between the two phases. This strategic integration promotes substantial modulation of the electronic environment, optimizes the availability of electrochemically active sites, and ultimately elevates catalytic effectiveness toward both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Electrochemical investigations demonstrate outstanding bifunctional catalytic performance of α-Fe/Ni3S2–2, achieving low overpotentials of 166 mV for HER and 289 mV at 10 mA cm-2 for OER. Additionally, when applied as a bifunctional catalyst aimed at overall water splitting, the composite exhibits an impressively low cell voltage of merely 1.72 V at a current density of 10 mA cm-2. Additionally, the robust structural integrity of the α-Fe/Ni3S2–2 catalyst guarantees prolonged operational stability, showing minimal performance degradation even under sustained electrolysis conditions. This study thus provides insightful strategies and opens novel pathways for the rational design and development of state-of-the-art bifunctional electrocatalysts by means of promising potential for scalable water splitting applications. © 2026 Elsevier B.V.