球形、花形和线状钒酸铋的可控合成及光催化性能(英文)

Controllable Synthesis and Photocatalytic Activity of Spherical, Flowerlike and Threadlike Bismuth Vanadates

通过无模板、无助剂的可控水热法,制备出球形、花形和线状钒酸铋(BiVO4),研究了其光学和可见光催化性能.通过X射线衍射(XRD)和透射电镜(TEM)观测其结构和形貌特征.XRD谱线显示,所制备的样品为单斜晶体结构.TEM结果表明,通过控制水热过程的反应参数可以得到不同形貌的纳米粉体.基于不同条件下制备的样品的微结构分析,提出了这些不同形貌的形成机制.紫外-可见漫反射光谱(UV-VisDRS)表明BiVO4样品的带隙能约为2.19-2.33eV.利用可见光(λ>420nm)照射下的罗丹明B(RhB)降解实验评价了BiVO4样品的光催化性能.结果表明,BiVO4的光催化活性比商用TiO2催化剂P25和掺氮TiO2(N-TiO2)高得多.所制备的球形BiVO4光催化效率最高,经可见光照射180min,RhB溶液的降解率可达100%.系统地研究了结构和形貌对不同pH值下制备的BiVO4样品光催化活性的影响.

Spherical, flowerlike, and threadlike bismuth vanadates （BiVO4） were synthesized via a controllable hydrothermal method without using any surfactant or template. The optical and photocatalytic properties of the BiVO4 samples were investigated. The phase structures of the BiVO4 samples were observed by X-ray diffraction （XRD）, which indicated that the as-prepared samples possessed monoclinic cells. Transmission electron microscope （TEM） observations showed that BiVO, crystals with different morphologies were fabricated simply by manipulating the parameters of the hydrothermal reaction. On the basis of the structural analysis of samples obtained under different conditions, a possible mechanism for the formation of these distinct morphologies was proposed. UV-visible diffuse reflectance spectra （UV-Vis DRS） of the samples revealed that the band gaps of the BiVO4 photocatalysts were about 2.19-2.33 eV. The as-prepared BiVO, photocatalysts exhibited higher photocatalytic activities toward the degradation of rhodamine B （RhB） under visible light irradiation （A 〉420 nm） than commercial P25 TiO2 and traditional N-doped TiO2 （N-TiO2）. Spherical BiVO, showed the highest photocatalytic activity of the samples, decolorizing up to 100% of RhB upon visible light irradiation for 180 min. The reason for the different photocatalytic activities of the BiVO4 samples fabricated at different pH was systematically studied by considering their structure and morphology.