Nanocrystalline TiO2 thin films: From hydrothermal preparation to photocatalytic activity

COLL 176

Chaochin Su, f10913@ntut.edu.tw, Tsai-Yin Yang, and Ji-Lian Chen. Institute of Organic and Polymeric Materials, National Taipei University of Technology, 1, Sec. 3, Chung-Hsiao E. Rd., Taipei, 106, Taiwan
Titanium dioxide (TiO2) thin film has attracted intensive interest due to its unique characteristics in various applications. In this work, thin films of nanocrystalline TiO2 were deposited onto glass substrates using a hydrothermal process. The initial sols were prepared by mixing the precursor, titanium (IV) n-butoxide with hydrochloric acid (HCl) and mechanically stirring until a white sol was obtained, followed by hydrothermal treatment at 220 ¢XC. The glass substrate were dip-coated or spin-coated and annealed at 450 ¢XC to result the TiO2 films. The coating conditions, such as spin rate and repeated coating cycle, affect the properties of the TiO2 films. The TiO2 film thickness varied from 0.4 to 7.5 ƒÝm. The morphology of the TiO2 films was examined by scanning tunneling microscopy. The grain size of TiO2 particulates is ~ 60 - 100 nm. The X-ray diffraction pattern for the annealed TiO2 powders (no dipping and coating) indicated the formation of rutile phase TiO2. To examine the photocatalytic activity of the as-prepared TiO2 films, the photodegradation of methylene blue was carried out. The possible correlation between the photocatalytic activity and the TiO2 preparation conditions is discussed.