Photoelectrocatalytic degradation of methyl orange over mesoporous film electrodes

Abstract

Mesoporous TiO₂ films and ion-doped photocatalytic films, displaying a worm-like pattern, have been synthesized by dip-coating of ITO glass into an organic–inorganic sol followed by aging and calcination of the coating at different temperature. The prepared films were investigated by X-ray diffraction (XRD), UV-Vis reflectance spectra, scanning electron microscope (SEM), transmission electron microscopy (TEM) and photoelectrochemical measurement, and were confirmed to be of mesoporous characteristic. Degradation of methyl orange (MO) has been performed using the new film electrodes under UV light and artificial solar light illumination. The influence of variables, such as applied bias, pH, supporting electrolyte, MO concentration and the load of the films, on the degradation of the dye was investigated. More than 97% degradation of MO was achieved under the feasible experimental conditions in 2 h photoelectrocatalytic reaction with UV light illumination and mesoporous film TiO₂/ITO as electrode. The activity of the mesoporous film V-TiO₂ was the highest of the newly synthesized films V-TiO₂, Ce-TiO₂, F-TiO₂ and pure TiO₂ under artificial solar light. The degradation ratio of MO was about 43% over 2 h reaction using V-TiO₂/ITO as the electrode. The activity of the mesoporous film under artificial solar light needs to be increased further.