中文摘要：

以单斜相V2O5·xH2O纳米线为前驱物,在温和条件下合成出V2O5·xH2O-BiVO4复合光催化剂.为理解产物的物相含量、形貌和光催化性质随合成时间延长而变化的情况,利用X射线衍射仪、场发射扫描电子显微镜、紫外-可见漫反射光谱仪以及光催化性质测试实验对三个典型的V2O5·xH2O-BiVO4样品（分别在反应6、12和24 h获得）进行了研究.分析结果表明：V2O5·xH2O-BiVO4纳米复合材料由V2O5·xH2O纳米线和BiVO4纳米晶组成,并且随合成反应时间的延长,产物中V2O5·xH2O纳米线的含量逐渐减少而BiVO4纳米晶的含量逐渐增加.光催化性质测试结果表明：V2O5·xH2O-BiVO4复合光催化剂在可见光（λ〉400 nm）辐射下降解亚甲基蓝时表现出了提高的光催化效率,其中在反应12 h获得的V2O5·xH2O-BiVO4样品体现出最好的光催化活性,这可能是由于其适当的组分含量和特殊的微结构有利于半导体激发和染料激发两种光催化机理的协同作用.

英文摘要：

V2O5·xH2O-BiVO4 composite photocatalysts were synthesized using monoclinic V2O5·xH2O nanowires as a precursor under mild conditions. To determine the synthesis-time-dependent phase content, morphology, and photocatalytic performance of the products, three typical V2O5·xH2O-BiVO4 samples were obtained at 6, 12, and 24 h. These samples were investigated using X-ray diffraction, fieldemission scanning electron microscopy, UV-visible diffusion reflectance spectroscopy, and a photocatalytic property test. The results indicate that the V2O5·xH2O-BiVO4 nanocomposites are composed of V2O5·xH2O nanowires and BiVO4 nanocrystals. As the reaction time was extended, the amount of V2O5·xH2O nanowires decreased gradually and that of the BiVO4 nanocrystals increased in the composite. The results of photocatalytic performance indicated that the 2O5·xH2O-BiVO4 composite photocatalysts exhibited enhanced photocatalytic efficiency for the degradation of methylene blue （MB） under visible-light irradiation （λ〉400 nm）. The V2O5·xH2O-BiVO4 sample obtained at 12 h exhibited the best photocatalytic activity, which is probably because of the appropriate proportion of components and the special microstructures of the sample that were favorable for a synergistic effect between the two photocatalysis mechanisms involving the excitation of the semiconductor and the excitation of the dye, respectively.