Preparation and photoelectrochemical properties of TiO₂ film electrode with high activity

The TiO₂ nanofilm electrodes were obtained by ion-exchange method using K₂Ti₂O₅ films as precursors which were prepared on tin-doped indium oxide (ITO) glass substrates by sol-gel process using Ti(n-OC₄H₉)₄ and CH₃COOK as raw materials. The structural composition and surface characteristics were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM). The photoelectrochemical properties of the TiO₂ films were assessed by electrochemical techniques using oxalic acid as organic pollutant. The results show that the crystalline state of the TiO₂ nanofilm is anatase, its particle size is about 30-150 nm and decreases with the decrease of preparation temperature of K₂Ti₂O₅ film. The TiO₂ film electrode has typical photoelectrochemical activities and high stability in 0.1 mol/L Na₂SO₄ solution. The photoelectrochemical activities of the TiO₂ film electrode increase and its flat-band potentials shift negatively in electrolyte solution with small amount of H₂C₂O₄ compared with those in the solution without H₂C₂O₄. The film electrode has stronger photo-response and more stable photocurrent high stability than those of TiO₂ film prepared by sol-gel method. The shift value of the flat-band potential of the TiO₂ film electrode is 0.140 V(vs SCE)and the saturated photocurrent density is 0.32 mA/cm².