Oxygen reduction reaction on silver electrodes under strong alkaline conditions

Oxygen reduction reaction (ORR) was studied on a silver polycrystalline electrode in different NaOH concentrations with a help of rotating disc and rotating ring disc electrodes. Soluble reaction intermediate was detected at all alkaline concentrations, but its concentration increased with an increase of the level of impurities. ORR is not NaOH concentration dependent at low concentrations (0.1 and 1 M). In 11 M NaOH ORR onsets at more positive potentials in the region where underpotential silver oxide formation shows less reversible behaviour. The nonlinear frequency response analysis spectra show significant qualitative difference with NaOH concentration indicating a high capability of this method for kinetic mechanism investigations. (C) 2019 Elsevier Ltd. All rights reserved.