Nanocrystalline sol–gel TiO2–SnO2 coatings: Preparation, characterization and photo-catalytic performance

In this study, preparation of SnO2 (0–30 mol% SnO2)–TiO2 dip-coated thin films on glazed porcelain substrates via sol–gel process has been investigated. The effects of SnO2 on the structural, optical, and photo-catalytic properties of applied thin films have been studied by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. Surface topography and surface chemical state of thin films were examined by atomic force microscopy and X-ray photoelectron spectroscopy. XRD patterns showed an increase in peak intensities of the rutile crystalline phase by increasing the SnO2 content. The prepared Sn doped TiO2 photo-catalyst films showed optical absorption in the visible light area exhibited excellent photo-catalytic ability for the degradation of methylene blue under visible light irradiation. Best photo-catalytic activity of Sn doped TiO2 thin films was measured in the TiO2–15 mol% SnO2 sample by the Sn4+ dopants presented substitution Ti4+ into the lattice of TiO2 increasing the surface oxygen vacancies and the surface hydroxyl groups.