Construction And Performance Of Bismuth Vanadate-based One-dimensional Nanomaterials With Upconversion Luminescence-photocatalytic Bifunctionality

Problem on water pollution has become the focus of modern society and industry. Photocatalytic technique as a green and efficient method, has received considerable attention to decompose toxic chemicals or organic contaminants. A series of bismuth-containing compounds are important photocatalytic materials, for example, bismuth vanadate nanomaterials exhibit photocatalytic activity under ultraviolet light and visible-light irradiation. They deserve in-depth discussion due to these properties. People have successfully employed different methods to fabricate bismuth vanadate nanomaterials of a variety of morphologies. Nevertheless, research on bismuth vanadate-based one-dimensional nano structured materials is still lacking. Electrospinning has been proved to be one of the best methods to fabricate low-dimensional nanomaterials owing to the advantages of simple operation and high efficiency. Therefore, fabrication of bismuth vanadate-based nanomaterials via electrospinning remains an important and creative subject of study.In this thesis, bismuth vanadate doped with rare earth ions( BiVO₄:Er³⁺,BiVO₄:Yb³⁺,Er³⁺)nanofibers, nanobelts were prepared via electrospinning process. The samples were characterized by XRD, SEM, EDS, up-conversion fluorescence spectroscopy, UV-Vis diffusion reflectance spectroscopy?UV–Vis DRS?. Photocatalytic activity of the samples was studied. The results show that BiVO₄:Er³⁺, BiVO₄:Yb³⁺,Er³⁺ nanofibers and nanobelts are monoclinic phase, the mean diameter of nanofibers is approximately 200 nm, the mean width of nanobelts is ca. 2 ?m. The up-conversion fluorescence spectra of samples demonstrate that BiVO₄:RE³⁺ nanomaterials are excellent up-conversion luminescence. The photocatalytic activities of the samples were studied through the degradation of RhB aqueous solution and the photocatalytic activity of the BiVO₄:RE³⁺ nanomaterials is obviously better than that of BiVO₄. BiVO₄:Yb³⁺,Er³⁺ nanofibers were used as the photocatalysts, the degradation rate of RhB solution was reached 99.9 % under the stimulated solar light irradiation for 70 min, but in the same conditions, the degradation rate of RhB solution is only 67.5 % when BiVO₄ nanomaterials is used as the photocatalysts. In the end, possible photocatalytic mechanism is also proposed, and some meaningful results are obtained. These findings lay solid foundations for the future study of performances of bismuth nanomaterials.