铝基板的界面扩散对薄膜型TiO_2光催化活性的影响

Influence of Interface Diffusion between Al Substrate and TiO_2 Film on Photocatalytic Activity

以钛酸四丁酯为前驱体,采用溶胶.凝胶法在铝基板表面制备了纳米晶TiO_2薄膜.运用XRD、SEM和XPS对制得的薄膜进行表征,并测试了薄膜光催化降解亚甲基蓝(MB)的活性.结果表明,TiO_2薄膜样品在450℃焙烧30 min后,晶粒排列比较致密,粒径为10-20 nm,并与铝基板紧密结合;薄膜与铝基板发生了明显的界面扩散,薄膜中的Al元素来自铝基板的界面扩散,且界面层很宽,扩散层厚度约为75 nm;界面扩散的发生直接导致了TiO_2薄膜的光催化活性下降.但随着薄膜厚度增加,铝基板对TiO_2薄膜降解亚甲基蓝催化活性的影响不断减小.

TiO2 nano-crystalline films on Al substrate were prepared from tetra-n-butyl titanate by sol-gel method. The synthesized TiO2 films were characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）and X-ray photoelectron spectroscopy（XPS）.The photodegradation activity of methylene blue（MB）solutions under UV irradiation was studied.The results indicated that the TiO2 particles could be built up from crystallites ranging from 10 nm to 20 nm and had a dense bonding.The interface diffusion between TiO2 and Al substrate takes place at calcination temperature of 450℃for 30 min and Al element diffuses into TiO2 film from Al substrate,forming a diffusion layer with a thickness of about 75 nm.The interface diffusion between TiO2 and Al substrate leaded to the inferior photocatalytic activity.The influence of Al substrate on photodegradation activity of MB solutions became less and less as the thickness of the thin film increased.