WO_3/Ag_3VO_4复合光催化剂的制备及其可见光催化性能

采用超声辅助沉淀法—浸渍法制备了WO3/Ag3VO4复合光催化剂,对其进行了表征,考察了其在可见光条件下对罗丹明B的催化降解性能,并对催化机理进行了探讨。表征结果显示:WO3紧密包覆在Ag3VO4颗粒的表面,并未改变Ag3VO4的晶体结构;与Ag3VO4和WO3相比,WO3/Ag3VO4的吸收带边发生了红移。实验结果表明:w(WO3)为3.5%时,WO3/Ag3VO4对罗丹明B的可见光催化降解效果最好;在光催化剂加入量0.8 g/L、初始罗丹明B质量浓度10 mg/L的条件下,于室温下光照180 min时的罗丹明B去除率达95.76%,TOC去除率达96.5%;WO3与Ag3VO4在能带间的耦合作用下形成异质结结构,很好地抑制了光生电子-空穴对的复合。

Preparation of WO3/Ag3VO4 composite photocatalyst and its photocatalytic activity under visible light irradiation

WO3/Ag3VO4 composite photocatalyst was prepared by ultrasound assisted precipitation- impregnation process,and its structure was characterized. Its photocatalytic activity was evaluated by photocatalytic degradation of rhodamine B under visible light irradiation,and the photocatalytic mechanism was discussed. The characterization results show that:The surface of Ag3VO4 is closely coated by WO3,but WO3 has no effect on crystal structure of Ag3VO4;Compared with Ag3VO4 and WO3,the optical absorption edge of WO3/Ag3VO4 shifts towards the longer wavelength side. The experimental results show that:The photocatalytic degradation effect of rhodamine B is the best whenw(WO3) is 3.5%;When the photocatalyst dosage is 0.8 g/L and the initial mass concentration of rhodamine B is 10 mg/L,the removal rates of rhodamine B and TOC are95.76% and 96.5% respectively,after 180 min of visible light irradiation at room temperature;Heterojunction structure can be formed with WO3 and Ag3VO4 due to the coupling effect between bands,which can effectively restrain the recombination of photo-induced electron-hole pair.