WO3/Ag3VO4复合光催化剂的制备及其可见光催化性能

Preparation of WO_3/Ag_3VO_4 composite photocatalyst and its photocatalytic activity under visible light irradiation

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。

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 when w （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 are 95.76% 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.