Preparation of TiO2 photocatalyst film and its catalytic performance for 1,1′-dimethyl-4,4′-bipyidium dichloride decomposition

A pure TiO2 colloidal solution for a catalyst with a high photocatalytic activity was obtained by thermal hydrolysis of titanium tetra-iso-propoxide (TTIP). The TiO2 film on pyrex plate, which was dip-coated with the colloidal solution, was characterized by XRD and SEM analyses. It was confirmed that the TiO2 film exhibited a uniform anatase structure with a particle size <45 nm and the film thickness was about 200 nm in one-time coating. To investigate the performance for 1,1'-dimethyl-4,4'-bipyidium dichloride (Paraquat) destruction, the TiO2 film was directly fixed on the UV-Iamp by the dip-coating method. The conversion of Paraquat remarkably increased by the film prepared by the hydrothermal method compared with the film prepared by the sol-gel method; in particular, the conversion reached above 95% after 15 h. In addition, the TiO2 film prepared by the hydrothermal method was stably attached on the UV-Iamp surface after reaction. But the film prepared by the sol-gel method was partially taken off the UV-lamp surface. Therefore, in this study, it was confirmed that the hydrothermal method was very reliable method for the synthesis of TiO2 thin film with high catalytic performance. (C) 2002 Elsevier Science B.V. All rights reserved.