Quantification of Reactive Oxygen Species Produced from Electrocatalytic Materials

Oxygen electrochemistry goes beyond O2, as the formation of reactive oxygen species (ROS) such as H2O2 and O3 during water oxidation is key in the destruction of persistent pollutants in water remediation technologies as well as in the degradation of fuel cell and electrolyzer components. In this study, we developed an in situ method utilizing the rotating ring-disk electrode technique to quantify the formation of O2, O3, and H2O2 species across a broad pH range (1-8.3). Oxygen selectivity trends over Pt, IrO2, and PbO2 surfaces reveal that even O2 evolution catalysts may produce small yet measurable amounts of ROS, further modulated by pH and electrode potential. These findings emphasize the need to probe the selectivity of oxygen electrochemistry for a more complete picture of advanced materials for electrochemical technologies.