Visible-light photocatalysts BiVO4 with different crystal structures and morphologies were prepared via a mild additive-free hydrothermal method. The as-prepared samples were well-determined by X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis diffuse reflectance spectroscope (DRS) and low-temperature N2 adsorption. The results indicated that both hydrothermal temperature and pH value of reaction solution had significant influence on the formation of crystal structures. Hydrothermal temperature of 180℃ and acidic condition facilitated the formation of monoclinic BiVO4. The pH value of reaction solution also affected the morphologies of samples remarkably, which resulted in three different types: sheet-, cube- and rod-like shapes. All the samples were applied to the photodegradation of methylene blue (MB) under visible light and sheet-like BiVO4 obtained in pH=2 reaction solution exhibited the best photocatalytic activity (4 h, 92.0%). In addition, influence factors of this photocatalytic system were thoroughly investigated, which included photocatalyst dosage, initial concentration and the existence of electron acceptors. The optimal photocatalytic condition was as follow: the dosage of catalyst was 1.0 g/L, the initial concentration of methylene blue was 10 mg/L, and KBrO3 was used as electron acceptor.%采用水热法,无需添加剂,通过调控反应液pH值和反应温度制备了不同结构和形貌的BiVO4可见光催化剂.利用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射(DRS)和低温氮吸附等手段对样品进行表征,结果显示:水热温度与反应液pH值对晶体结构有很大影响,180℃水热温度和酸性条件有利于单斜相的生成.反应液pH值对形貌也有很大影响,不同条件下得到了片状、立方状、棒状等不同形貌的BiVO4.同时以亚甲基蓝为降解对象,考察了所制备BiVO4的可见光催化活性.其中,pH值为2,反应液中制备的片状单斜相BiVO4具有最高的光催化活性(4 h达92.0％).此外,还考察了光催化剂用量、亚甲基蓝浓度和电子受体的存在对光催化过程的影响,结果表明:当催化剂用量为1.0 g/L,亚甲基蓝浓度为1o mg/L,KBrO3为电子受体时光催化效果最佳.
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