Doping Ruthenium Oxides with P-Block Metals Enables Water Oxidation via O-O Coupling Reactions

The practical deployment of proton exchange membrane electrolyzers is limited by the lack of highly efficient and durable anodic electrocatalysts. Here, we report an indium-doping strategy that promotes O-O coupling at bimetallic sites in RuO2, thereby enhancing oxygen evolution reaction (OER) performance. As a result, the designed In-RuO2 catalyst achieves an improved balance between activity and durability. It exhibits low overpotentials for both the OER and hydrogen evolution reaction (HER) over a wide pH range, requiring overpotentials of only 227 mV and 229 mV for the OER and 33 mV and 20 mV for the HER at 10 mA cm-2 in 0.5 M H2SO4 and 1.0 M KOH, respectively. In addition, it maintains stable operation for 90 h during the OER process in acidic media. In situ experiments, combined with theoretical calculations, suggest that In-Ru binuclear sites favor the oxide pathway mechanism (OPM) during OER. Furthermore, the incorporation of In atoms suppresses Ru dissolution. This study provides insight into the regulation of the reaction pathway through atomic doping in RuO2 and offers guidance for the design of OER catalysts with improved activity and stability.