Interfacial engineering of FeWO4/Fe2O3 homometallic heterojunctions for synergistic electrocatalytic water splitting

Abstract

Heterojunction construction is a crucial strategy in developing efficient electrocatalysts. However, their structures are not well-suited for achieving high-performance dual functions due to the surface reorganization resulting from the separation and redeposition of heterometallic centers. A novel FeWO₄/Fe₂O₃ catalyst was synthesized via pyrolysis to form a homometallic heterojunction, which exhibits remarkable electrocatalytic activity towards oxygen/hydrogen evolution reactions and overall water splitting. DFT calculations indicate that the FeWO₄/Fe₂O₃ heterojunctions regulate the electronic states, accelerate charge transfer, and enhance electrocatalytic activity. As anticipated, the FeWO₄/Fe₂O₃ heterostructure produced in 1 M KOH solution exhibits a low overpotential of 315 mV at 10 mA cm⁻² for the OER and 38 mV for the HER. Furthermore, the FeWO₄/Fe₂O₃ electrode can efficiently operate at a voltage of only 1.62 V in an electrolyzer to produce a current density of 10 mA cm⁻² and maintain exceptional stability during prolonged operation at a constant voltage.