Preparation of Al/TiO2 nanometer photo-catalyst film and the effect of H2O addition on photo-catalytic performance for benzene removal

The nanometer particles of Tio(2) and Al/TiO2 (1.0, 5.0, and 10.0 wt.%) were obtained by a sol-gel method. The TiO2 and Al/TiO2 particles were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), DLS, TG-DSC, and UV-Vis spectroscopy. The TiO2 and Al/TiO2 Particles exhibited a uniform anatase structure with particle size below 100-150 nm. Obtained Al/TiO2 particles absorbed wavelengths above 270 nm. The absorption band was shifted to longer wavelength (red shift). In addition, the surface area of 10.0 wt.% Al/TiO2 was very large (290 m(2)/g), compared with that of pure TiO2 (50-70 m(2)/g). From XRD results, we suggested that a new structure connected by Al-O-Ti framework was generated. In particular. for Al/TiO2, the anatase structure was stable after thermal treatment at 800 degreesC, while pure TiO2 was easily transferred to the rutile type after thermal treatment above 700 degreesC. On the other hand, the conversion of benzene was higher in pure TiO2 than in Al/TiO2 without H2O addition during reaction; however, the conversion surprisingly enhanced about 40% over 10.0 wt.% Al/TiO2 catalyst with 10 mol-wt.% H2O addition in a continuous photo-reaction system. In addition, no photo-catalytic deactivation was found over 10.0 wt.% Al/TiO2 until 10h, when 10 mol-wt.% H2O was added during the benzene decomposition reaction. (C) 2003 Elsevier B.V. All rights reserved.