中文摘要：

以Bi（NO3）3·5H2O和Na2WO3·2H2O为原料,以柠檬酸为络合剂,采用辅助水热法制备了Bi2WO6纳米片,运用X射线衍射、扫描电镜、场发射高分辨透射电镜、拉曼光谱、红外光谱和紫外-可见漫反射光谱等手段对样品进行了表征,并考察了该催化剂光催化去除甲基橙反应性能.结果表明,通过调节体系的pH值可制得结晶度良好的正交晶系钨铋矿型结构的Bi2WO6纳米片状晶体.柠檬酸的添加使得制备的Bi2WO6颗粒的拉曼光谱特征峰发生蓝移,紫外-可见光吸收边发生红移,其能带隙减小至2.55eV.光催化反应结果表明,催化剂制备时体系pH值是影响其可见光催化活性的主要因素,pH=7.0时制备的Bi2WO6纳米片光催化效率最高,可见光照射15min,浓度为10mg/L甲基橙溶液的降解率可达到100%,且循环使用5次后,其光催化活性并没有明显降低,表明Bi2WO6是一种稳定有效的可见光催化剂.

英文摘要：

Bi2WO6 nanosheets with highly efficient photocatalytic activity under visible light irradiation were prepared by a hydrothermal method using Bi（NO3）3·5H2O and Na2WO3·2H2O as starting materials and citric acid as the chelating agent.The properties of the as-prepared samples were investigated by X-ray diffraction,field emission high resolution transmission electron microscopy,Raman spectroscopy,and UV-Vis diffusion reflectance spectroscopy.The photocatalytic properties of the Bi2WO6 catalyst were also investigated.The results show that Bi2WO6 nanosheets with orthorhombic structure can be obtained by adjusting the pH value of the reaction system.Compared with the Bi2WO6 catalyst prepared without citric acid,the Raman bands of the nanosheets assisted with citric acid present blue shift and show a significant red shift in the absorption band and its band gap was narrowed to 2.55 eV.The pH value of the reaction system is the main factor affecting the visible light-driven photocatalytic activity.The Bi2WO6 sample prepared at pH = 7.0 shows a higher photocatalytic activity.Over this catalyst,the 100% degradation of methyl orange solution（10 mg/L） is obtained after visible light irradiation for 15 min.In addition,after 5 recycles,there is no significant decrease in its photocatalytic activity,indicating that Bi2WO6 is a stable photocatalyst for degradation of methyl orange under visible light irradiation.