Electrochemical oxidation of phenol at Ti/Ru0.3Pb(0.7-x)TixOy electrodes in aqueous media

In this work, we investigated the elimination of phenol from aqueous acidic solutions by electrochemical oxidation at Ti/Ru0.3Pb(0.7-x)TixOy oxide electrodes. The process was studied by carrying cyclic voltammetry (CV) and electrolysis experiments in acidic media (HClO4 0.1 mol L-1) as a function of the electrode composition. CV in the presence of phenol showed that the electrocatalytic response of the electrode increases with increasing the Pb content. Large phenol degradation was obtained with the introduction of PbOx. The Pb-free composition (Ti/Ru0.3Ti0.7O2) led to the lowest performance for phenol degradation. High-pressure liquid chromatography and total organic carbon techniques were used in order to quantify electrode efficiency. The formation of benzoquinone as well as of some aliphatic acids was observed. Electrodes with nominal composition Ti/Ru0.3Pb0.5Ti0.2O2 and Ti/Ru0.3Pb0.7O2 provided optimum response for phenol oxidation at the end of the electrolysis investigation (5 h), with high yields of total organic-carbon reduction. (c) 2006 The Electrochemical Society.