Inhibiting Ru over-oxidation in RuO2 via vanadium doping for efficient oxygen evolution reaction toward acid and alkaline water electrolysis

Enhancing the oxygen evolution reaction (OER) activity and stability of ruthenium (Ru)-based catalysts is crucial for replacing higher-cost iridium (Ir)-based materials in water electrolysis field. In this work, a series of vanadium (V)-doped RuO 2 (V x Ru 1- x O 2 ) were successfully synthesized and employed as the OER catalysts towards proton exchange membrane (PEM) and alkaline water electrolyzer. The doped V can reduce the oxidation state of Ru and diminish the covalency of the Ru-O bond. In-situ FTIR and DEMS results demonstrate the leaching of lattice oxygen during is inhibited during the OER. As a result, the V 0.375 Ru 0.625 O 2 catalyst exhibited superior OER activity and long-term stability across a broad pH range. Specifically, it delivered a current density of 10 mA cm −2 at overpotentials of 236 mV in 0.5 M H 2 SO 4 and 228 mV in 1 M KOH electrolyte. Furthermore, the catalyst could operate stably for a long time during the OER process, with no significant dissolution of Ru species. This work provides valuable insights into strategies for enhancing the intrinsic catalytic activity and stability of RuO 2 through modification with the V dopants, offering a promising pathway for developing cost-effective and high-performance OER catalysts for water electrolysis.