聚乙二醇对非水解溶胶-凝胶法制备TiO_2薄膜结构及性能的影响(英文)

EFFECT OF POLYETHYLENE GLYCOL ON MICROSTRUCTURE AND PHOTOCATALYSIS OF TiO_2 THIN FILMS BY NON-HYDROLYTIC SOL-GEL PROCESSING

采用非水解溶胶-凝胶法制备了多孔TiO_2光催化薄膜。用紫外光照甲基橙的降解实验研究了聚乙二醇(polyethylene glycol,PEG)分子量和添加量对TiO_2薄膜光催化活性的影响。应用场发射扫描电镜分析了薄膜的显微结构与其光催化性能的关系。结果表明:当PEG的相对分子量为1 000,PEG与TiCl_4的摩尔比为0.1时,薄膜的比表面积大,薄膜颗粒细小,薄膜中存在均匀分布的大量微小孔隙,其光催化性能最佳。PEG的分子量和加入量过高或过低均会降低薄膜的光催化性能。当PEG的分子量过小或其加入量过少时,TiO_2薄膜显微结构的特点是晶粒粗、孔隙数量多和孔径大。PEG的分子量过大或加入量过多,薄膜的颗粒细小,但前者导致薄膜致密而后者又促使薄膜多孔。

Porous TiO2 photocatalytic thin films were prepared by the non-hydrolytic sol-gel route. The effect of the molecular mass and content of polyethylene glycol （PEG） on the photocatalysis of TiO2 films was investigated by the photocatalytic degradation of methyl orange under ultraviolet irradiation. The relationships between the microstructure of TiO2 films and their photocatalysis were investigated by field emission scanning electron microscopy. The results show that when the relative molecular mass of PEG is 1 000 and the molar ratio of PEG to TiCl4 is 0.10, the TiO2 film has fine grains and a great number of evenly-dispersed micropores, a large specific area, and consequently the best photocatalytic performance. When the molecular mass of PEG is higher or lower than 1 000, the photocatalysis of TiO2 films decreases. The TiO2 films have large crystal sizes and a great number of big pores when the molecular mass of PEG is too small or its content is too low. The films have fine crystal grains when the PEG molecular mass or PEG content is too high, yet the film is dense when the PEG molecular mass is too high, while the film is porous when prepared with an excessively high PEG content.