Photocatalytic activity and hydrophiiicity of SiO2-TiO2 thin films

摘要

SiO2-TiO2 thin films with various SiO2 contents have been prepared from titanium butoxide solution and anhydrous ethanol as a solvent by a sol-gel dip coating technique. The thermal properties of the SiO2-TiO2 (5 mol% SiO2) gels were analyzed by thermogravimetry and differential scanning calorimetry (TG-DSC). Structural properties of the SiO2-TiO2 thin films at different heat treatment temperatures were analyzed by x-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM) and atomic force microscopy (ATM). The results show that with increasing SiO2 content from 5 to 30 mol%, TiO2 crystals become smaller because the contact between TiO2 particles is prevented by SiO2. The photocatalytic performance of the SiO2-TiO2 films was examined by considering the degradation of Rhodamine B. The hydrophiiicity of the SiO2-TiO2 films was also investigated by measuring the surface contact angle between the SiO2-TiO2 films and water under different conditions. The results showed that by adding less than 30 mol% SiO2, the photocatalytic activity of the SiO2-TiO2 films increased during UV irradiation due to suppression of' anatase crystal growth during calcination. The hydrophiiicity can also be improved and the super-hydrophilic state can be maintained for a long time.