Siberian Federal University

The photooxidation of ethylene glycol (EG) on nanotube TiO2 electrodes synthesized by anodization of titanium foil was studied in aqueous electrolytes at different pH levels (5.9 and 13.6) and EG concentrations (0.01 to 10 M). Chronoamperometry, linear potential scanning, and electrochemical impedance spectroscopy (EIS) were shown that electrochemical reduction activation of electrodes by cyclic voltammetry (CV) leads to an increase in the surface states density. This contributes to the effective e-/h+ exciton separation, an increase in the charge transfer rate at the electrode/electrolyte interface, and, accordingly, the photocurrent density. The photocurrent was found to increase with EG addition, with this magnitude being affected by EG concentration, pH level, and the surface state of the photoanode. The EIS results aligned with transient photocurrent measurements, indicating a competition between water oxidation and EG oxidation. EG oxidation proceeded through various pathways, including both direct and indirect hole transfer to molecules adsorbed on the electrode surface