The uniform transparent TiO2 nanometer thin films were prepared on soda-lime glass via sol-gel method and calcined at 500 ℃ for 2 h.The as-calcined TiO^ thin films were treated in 2 mol·L~ CH3COOH aqueous solution for 24 h, finally, the as-treated TiO2 thin films were again heat-treated at 100 and 500℃ for 0.5 h, respectively.The structures and photocatalytic activity of TiC_2 thin films before and after surface acid treatment were characterized and evaluated by UV-vis, SEM, XED, XPS and photocatalytic decoloration of methyl orange aqueous solution, respectively.lt was found that the photocatalytic activity of TiO_2 nanometer thin films was enhanced after CH_3COOH treatment. Moreover, the films showed higher photocatalytic activity at 500 ℃ than at 100 ℃ after surface acid treatment.

Key words: TITANIUM DIOXIDE, NANOPHASE MATERIALS, SOL-GEL PROCESS, ACETIC ACID, PHOTOCATALYSIS, SEM, XRD, XPS