Photoelectrochemical properties and crystalline structure change of Sb-doped TiO₂thin films prepared by the sol-gel method

Ti_1−XSb_XO₂samples were obtained from dip-coating sol-gel method and a subsequent anneal at 450 °C. They had an average crystallite size of 13.3–20 nm. Cyclic voltammograms taken under ultraviolet (UV) and Xe lamp illumination in a 0.5 M Na₂SO₄electrolyte showed that the Sb-doped samples had greater photocurrent densities than pure titania electrode, with an optimal Sb concentration of 0.2%. Oxidative peaks were observed in the cyclic voltammograms obtained in the dark after certain exposure duration to UV light. X-ray diffraction patterns and Raman spectra show a phase transformation from brookite to anatase in the samples with Sb concentration up to 0.2%. Ti⁴⁺ions were substituted by Sb to form the anatase structure of Sb–O–Ti, improving the crystallization efficiency. The Sb–Sb bonds were formed due to the introduction of excessive Sb atoms.