Ir x Ru 1− x O 2 /WO 3 heterostructure for efficient acidic oxygen evolution reaction

Abstract Achieving simultaneous activity and durability for acidic oxygen evolution reaction (OER) remains a central challenge; interfacial heterostructuring offers a route to stabilize Ru while exploiting its high intrinsic activity. Here we report a heterostructured nanosheet catalyst IrxRu1−xO2/WO3 that leverages interface-driven electronic and geometric modulation to boost OER performance. Density functional theory calculations indicate that interfacial modulation steers the OER toward the oxide pathway mechanism (OPM), effectively lowering the energy barrier of the potential-determining step. In electrochemical tests, the catalyst delivers an overpotential of 223 mV at 10 mA·cm−2 under acidic conditions and maintains an essentially constant potential over 120 h of continuous chronopotentiometry. An OER–oxygen reduction reaction (ORR) coupled electrochemical oxygen generator (EOG) single cell was constructed to evaluate the catalyst’s performance, demonstrating a current density of 664 mA·cm−2 at 1.2 V and an oxygen production rate of 126 mL·min−1. The IrxRu1−xO2/WO3 exhibits good stability during 320 h of continuous operation, with a current decay of less than 3%, which is significantly lower than that of the commercial IrO2 (current decay of ~ 15%). These results establish interfacial heterostructuring as a practical route to combine high activity with long-term durability in acidic OER, enabling efficient, robust electrochemical oxygen generation.