金红石型TiO2/ZnTiO3复合材料的制备及其光催化性能

Preparation and Photocatalytic Activity of Rutile-TiO2/ZnTiO3 Composite

采用溶胶-凝胶法制备了金红石型TiO2/ZnTiO3复合光催化剂,对其进行650℃保温1 h的热处理;通过X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、荧光光谱(PL)对样品进行表征,并以亚甲基蓝(MB)溶液为目标污染物,研究了样品的光催化性能。结果表明,TiO2为金红石结构,随着Zn/Ti量比增加,TiO2晶粒尺寸减小;当Zn/Ti的量比达到2%时,有新相ZnTiO3生成。TiO2/ZnTiO3(Zn/Ti=8%)展现出最高的光催化活性,这归因于表面羟基含量增加以及形成的TiO2/ZnTiO3半导体复合结构加快了光生电子与空穴的转移。反应进行90 min后,对MB的降解率达到68.3%,反应速率常数k为0.012 min-1,分别为纯TiO2的1.85倍和3倍。

The rutile-TiO2/ZnTiO3 composite photocatalysts were synthesized by a sol-gel method,and were heat treated at 650℃for 1 h.The obtained samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS)and photoluminescence spectra(PL).The photocatalytic performance of samples was studied taking the degradation of methylene blue(MB)as the target reactant.The results show that the crystal structure of TiO2 is rutile phase and the grain size of TiO2 decreases with the increasing Zn/Ti molar ratio.ZnTiO3 forms when the Zn/Ti molar ratio reaches 2%.TiO2/ZnTiO3(Zn/Ti=8%)exhibits the highest photocatalytic activity,which can be attributed to the increase of surface hydroxyl content and the formation of TiO2/ZnTiO3 semiconductor composite structure,accelerating the transfer of photogenerated electrons and holes.After 90 minutes of reaction,the degradation rate of MB by TiO2/ZnTiO3(Zn/Ti=8%)reaches 68.3%and the reaction rate constant k is 0.012 min-1,which are 1.85 times and 3 times higher than that of pure TiO2.