HNO3处理对TiO2纳米薄膜的光催化活性和表面微结构的影响

通过sol-gel工艺分别在钠钙玻璃和预涂SiO2涂层的钠钙玻璃基体上制备了TiO2光催化纳米薄膜．然后用1mol／L HNO3水溶液对煅烧后的薄膜进行酸处理。用X射线光电子能谱(XPS)、扫描电镜(SEM)和紫外可见光谱(UV—VIS)对酸处理前后TiO2纳米薄膜进行了表征。用甲基橙水溶液的光催化脱色来评价TiO2薄膜的光催化活性。结果表明：SiO2涂层能有效阻止钠离子从玻璃基体向TiO2薄膜的扩散，普通玻璃表面的TiO2纳米薄膜经HNO3处理后，薄膜的光催化活性明显增强。这是由于TiO2纳米薄膜中的钠离子浓度降低以及表面羟基含量增加的缘故。

Effects of HNO3 Treatment on Photocatalytic Activity and Surface Microstructures of Sol-gel Derived TiO2 Nanometer Thin Films

TiO2 nanometer thin films were prepared on soda-lime glass and pre-coated SiO2 soda lime glass via a sol-gel method, respectively. The as-calcined TiO2 nanometer thin films were then treated by dipping them in 1mol/L HNO3 aqueous solution. The TiO2 nanometer films before and after surface acid treatment were characterized by UV-VIS spectrophotometry, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), and photocatalytic activity of the thin films were evaluated by photocatalytic decoloration of methyl orange aqueous solution. The results show that SiO2 layer can effectively retard the diffusion of Na ions from glass substrates to TiO2 films. The photocatalytic activity of TiO2 thin films is significantly enhanced after treated with HNO3 solution. The enhancement of the activity is ascribed to the reduction of sodium ions and the increase of the surfacehydroxyl content in the TiO2 films.