Clay Collin D, Mueller Chelsea M, Rich Christopher C, Schatz George C, Bruggeman Peter J, Frontiera Renee R
University of Minnesota - Twin Cities, Department of Chemistry, Smith Hall, 207 Pleasant St SE, Minneapolis, Minnesota 55455-0431, United States.
Northwestern University, Department of Chemistry, 2145 Sheridan Rd., Evanston, Illinois 60208-3113, United States.
J Phys Chem Lett. 2024 Jul 11;15(27):6918-6926. doi: 10.1021/acs.jpclett.4c01323. Epub 2024 Jun 27.
Plasma-driven solution electrochemistry (PDSE) uses plasma-generated reactive species to drive redox reactions in solution. Nonthermal, atmospheric pressure plasmas, when irradiating water, produce many redox species. While PDSE is a promising chemical tool, there is limited insight into the mechanisms of the reactions due to the variety of short-lived reagents produced. In this study, we use aniline as a model system for studying redox mechanisms of PDSE. We show that the plasma irradiation of aqueous aniline solutions drives the formation of polyaniline oligomer, which is suppressed under acidic starting conditions. The addition of (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO), a radical scavenger, decreases the formation of oligomer by 80%, and the addition of superoxide dismutase fully hinders oligomerization. These results lead us to conclude that the oligomerization of aniline by plasma irradiation is initiated by superoxide. This discovery provides novel insights into PDSE mechanisms and illustrates a potential method of harnessing superoxide for chemical reactions.
