Fig. 3: Electrochemical study of the viologen-modified film degradation.
Cyclic voltammograms (CVs, 28 cycles) of viologen-modified hydrogel films on glassy carbon electrodes (GCE) under 5% O2 in argon a in the absence and b in the presence of KI (0.1 M). CVs recorded under 100% argon are shown as black curves. c Normalized peak current amplitudes (anodic peak current (ipa) − cathodic peak current (ipc)) extracted from the reversible redox signals of the viologens overlapping with the catalytic wave for O2 reduction derived from the measurements shown in a and b. d Normalized peak current (ip) before and after O2 reduction derived from CVs under 100% argon (Supplementary Fig. 8). Error bars are defined as standard deviation. Average values and standard deviations were obtained from measurements at three individually prepared electrodes and then normalized by average ip values before O2 reduction. All measurements were performed with GCE (3 mm in diameter) coated with viologen-modified polymer with a surface coverage of 0.3 mg cm−2. Electrolyte: phosphate buffer (0.1 M, pH 7). Scan rate: 2 mV s−1. Rotation rate: 2000 r.p.m. Source data are provided as a Source Data file.
