SOL-GEL FILM-PREPARATION OF NOVEL ELECTRODES FOR THE ELECTROCATALYTICOXIDATION OF ORGANIC POLLUTANTS IN WATER

The electrochemical oxidation of phenol as a model contaminant, has be en studied using different electrode materials (Ebonex, Ebonex/PbO2, T i/SnO2) in water by means of cyclic voltammetry. Best results have bee n obtained with doped SnO2-films on titanium foils prepared by a sol-g el dip-coating technique. The cyclovoltammograms reveal a high overpot ential for oxygen-evolution, resulting in a well separated peak for th e oxidation of phenol. Improvements of the conductivities of the films and higher current densities for the oxidation were obtained by dopin g the film sol-gel solution with 10% Sb. Doping with fluoride increase d the conductivity, but decreased the oxidation peaks. The PbO2-coated Ebonex-electrodes were obtained by the galvanostatic deposition in an acidic PbNO3-solution. Upon the addition of phenol to the electrolyte , however, the electrodes did not show a separated oxidation peak. The oxidation peak is partially hidden by oxygen evolution. The electroch emical characteristics of the electrode material Ebonex is not signifi cantly changed by the addition of phenol to the electrolyte.