Improved photocatalytic activity of Sn4+-doped and undoped TiO2 thin film coated stainless steel under UV- and VIS-irradiation

TiO2 can be used as a photocatalyst because of its semiconductor property. If TiO2 is doped with transition metal ions, its electronic properties are modified. In this work, nanosized Sn4+-doped and undoped TiO2 (TiO2-Sn4+ and TiO2) particles have been synthesized without organic solvent by hydrothermal process at low temperature. Nano-TiO2 particulates having a doping ratio of about 5 [Sn4+/Ti(OBun)4; mol/mol%] allowed to coat the stainless steel substrate by spin-coating technique. The particles and the films were characterized by XRD, SEM, BET and UVNIS/NIR techniques. The photocatalytic performance of the films were tested for degradation of Malachite Green dye in solution under UV and VIS-lights. The results reveal that (a) nano-TiO2 particles are fully anatase crystalline form and are easily dispersed in water, (b) the coated surfaces are hydrophilic, (c) the photocatalytic activity of the TiO2-Sn 41 film is higher than that of the undoped TiO2 film under UV and VIS-light irradiation and, (d) TiO2-Sn4+ film can be repeatedly used with increasing photocatalytic activity compared to undoped TiO2 film. (c) 2006 Elsevier B.V. All rights reserved.