The conductivity of Poly(3,4-ethylenedioxythiophene) doped with poly(-styrenesulfonate), PEDOT:PSS can be modified by adding the so-called secondary dopant dimethyl sulfoxide (DMSO). Although this strategy is widely used, its mechanism and effect on Oxygen Reduction Reaction (ORR) performance have not been studied yet. Here, we present a broad study on DMSO doped PEDOT:PSS to find the effect of changes in the conductivity of polymer electrodes on ORR kinetics. We demonstrate the electrode electrical conductivity both without and with the electrolyte, thus their performance for ORR activity and selectivity towards H<sub>2</sub>O<sub>2</sub> evolution, to be governed by the degree of DMSO doping. From kinetic studies performed with rotating ring disk electrodes (RRDE), we observe a strong correlation between the activity of ORR and the electrical conductivity of electrodes. However, the selectivity and electron transfer number do not change much despite the variation in DMSO content/conductivity. We review the influence of electric conductivity on the diffusional and kinetic contributions to the total current. A series of experiments were conducted to investigate the influence of electrode geometry. This study provides a better understanding of the ORR using conducting polymer electrodes. The improved conductivity due to DMSO doping originates from enhanced charge carrier mobility due to enhanced structural order at the nanoscale, and the increase in ORR activity with conductivity correlates with the outer sphere electron transfer mechanism.

Understanding electrochemical oxygen reduction reaction at conducting polymer Poly(3,4-ethylenedioxythiophene)

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

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