ZnO/AgNbO_3光催化剂的表征及活性研究

Characterization and Photocatalytic Activity of ZnO/AgNbO_3

采用浸渍法合成ZnO/AgNbO3异质结光催化环境净化材料.利用X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电镜(SEM)、紫外漫反射(DRS)等分析方法对催化剂进行了表征.XRD分析结果表明,Zn的掺杂并未改变本体AgNbO3的晶型结构;随着Zn掺杂量和热处理温度的提高,异质结光催化剂体系中ZnO晶相结构逐渐出现;同时,XPS结果也说明Zn以ZnO的形式存在.DRS分析说明ZnO的引入有助于提高可见光区的吸收强度.无论在可见光还是紫外光照射下,光催化降解亚甲基蓝染料(MB)实验证明ZnO掺杂有利于提高AgNbO3的活性.当Zn掺杂量为3wt%,热处理温度为300℃时,紫外光照射3h下MB降解率达到93.5%.并对ZnO引入后光催化活性提高的机理进行了分析.

ZnO/AgNbO3 hetero-junction photocatalysts were prepared by impregnation method.The samples were characterized by X-ray diffraction（XRD）,X-ray photoelectron spectroscope（XPS）,scan electron microscope（SEM）and UV-Vis diffusion reflectance spectra（DRS）.The results indicated that Zn dopant did not change the crystal structures of AgNbO3.With increasing Zn content and calcination temperature,the ZnO phase formed in the ZnO/AgNO3.XPS analysis indicated that Zn2＋ existed as ZnO.The DRS spectra showed that Zn dopant enhanced the ability of visible light absorption of the ZnO/AgNbO3 samples.The photocatalysts doping with ZnO exhibited the enhanced photocatalytic activities for degradation of methylene blue（MB）under visible light and UV light irra-diation.The highest efficiency was obtained when the sample calcined at 300℃ with 3 wt% Zn content under UV lightirradiation.The mechanism of improving photocatalytic activity was also discussed.