M. Hosseini-Zori - Inorganic Pigment and Glazes Department, Institute for Color Science and Technology, Tehran, Iran

The aim of this investigation was the surface treatment of industrial ceramic tiles by sol–gel technique to improve at the same time the clean ability of glazed surfaces. Self-cleaning ZnO–TiO2 thin films were successfully prepared on ceramic tile using a sol–gel technique for photocatalytic applications. We investigated the phase structure, microstructure and optical properties of the coatings by using XRD, SEM and UV/Vis spectrophotometer. Four different solutions were prepared by changing Zn/Ti molar ratios such as 0, 0.1 and 0.3. Ceramic tiles were coated by solutions of Ti-alkoxide, Zn-chloride, glacial acetic acid and isopropanol. The obtained gel films were dried at 100°C for 60min and subsequently heat-treated at 500°C for 50min in air. anatase and ZnO phases were determined in the coatings. The microstructural observations demonstrated that ZnO content improved surface morphology of the films and the thickness of film and surface defects increased in accordance with number of dipping. For the optical property, the absorption band of synthesized powders shifted from the UV region to the visible region according to the increase of the amount of ZnO coupled semiconductor. The oxide films were found to be active for photocatalytic decomposition of methylene blue.

Sol–Gel- Zn–TiO2 coatings- Ceramic- Photocatalytic application