Photocatalytic Degradation of Azo Dye Using a Novel Composite Elelctrode

A novel composite electrode which had functions of synthesizing H2O2and photocatalysis was reported and characterized by X-rays diffraction and SEM. This double function composite electrode was prepared by the Sol-gel method of loading photocatalyst TiO2/AC on a novel carrier which could synthesize H2O2and separate photogenerated electrons(e-) and holes(h+) efficiently, resulting in improving the reaction rate. In the photo reactor, the composite electrodewas used as a cathode, Ru-Ti-O electrode used as an anode lower pressureHg lamp used as a light source. The combining oxidation of photochemistry and photocatalysis existed at the same interface of electrode-solution. Experiments showed thatTiO2was an anatase phase and homogeneously distributed on the surface of active carbon (AC). So, the effective surface area of the photocatalysts and their absorbability for organic molecules could be increased, providing high concentration environments of organic molecules around TiO2particles and resulting in the enhancement of photocatalytic activity ofTiO2. Although the surface of air electrode was covered with photocatalystTiO2/AC, the current efficiency in H2O2synthesis of the composite electrode was higher as the current density was 15 A/cm2and the efficiency reached about 80%. The experimental results also showed that the composite electrode played an important role in enhancing the oxidation rate of azo dye molecule (activated red K-2BP), in 3 min, the decolorizing rate could reach about 49%, and the removing COD rate could reach about 47% only in 80 min.