Reactive oxygen species (ROS) formation at electrodes in aqueous electrolytes are critical processes for the electrochemical remediation of wastewaters, the electrosynthesis of fuels and molecules, and the functioning of  electrocatalysts. Despite their importance in these processes, detecting ROS is challenging due to their short lifetime and difficulties in their spectroelectrochemical characterization. Nonetheless, a comprehensive understanding and quantification of surface and near-surface electrochemical ROS generation is required to close the loop in fundamental aspects of these studies. To this end, a longstanding interest in our group has been the development of analytical techniques to detect and quantify ROS using scanning electrochemical microscopy (SECM) in various modes. For instance, the development of SECM in the Surface Interrogation mode (SI-SECM) championed by our group has enabled the determination of the surface coverage, speciation, and reaction dynamics of adsorbed ROS onto various electrodes and photoelectrodes. However, detecting these highly reactive intermediates when discharged in the vicinity of electrodes had remained elusive using our SECM technique.<br/><br/>In this talk, we will present a new strategy for detecting electrogenerated hydroxyl radicals formed at various electrodes under conditions for water oxidation. By prompting adduct formation at the vicinity of an operating electrode and using the generation-collection mode of SECM, we were able to detect these fleeting intermediates with high signal to noise ratio, and in real-time as the electrode potential modulated their production. We thoroughly tested our strategy using computational and spectroscopic techniques. A career-long interest, I will discuss our pathway and ultimate intentions in creating a powerful toolbox for characterizing ROS of relevance to energy and environmental science.

Real-time quantification of hydroxyl radical using scanning electrochemical microscopy: A milestone in a career-long interest of detecting oxygenated reactive intermediates at electrodes

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.