Photocatalytic activity of TiO2 films prepared by sol–gel and electrodeposition on the decolourization of monoazo dyes

TiO2 films were prepared effectively using titanium tetraisopropoxide sol by simple electrodeposition technique on conductive indium tin oxide plates followed by annealing. The films thus obtained were characterized by XRD, FT-IR, SEM, UV-DRS, AFM and PL analyses. X-ray patterns of non-annealed film show the amorphous nature, while the annealed film indicates the formation of anatase. This distinction is also observed from AFM images. The band gap energy obtained from UV-DRS spectra of the annealed film was 1.8 eV. This narrowed band gap can be attributed to the presence of hydroxyl groups and the existence of Ti–OH bonds as evidenced from FT-IR spectra. The photocatalytic activity of the films was tested with model pollutants such as Reactive Red 2 and Disperse Yellow 231 dyes. The photocatalytic degradation performance of the film depends on the concentration of dye, pH of the solution and treatment time. Study on the electrode after repeated usages show that the electrode can be reused up to 20 times with percentage of deficiency <15 %.