Morphology Control And Properties Of W And C Doped Bismuth Vanadate

The rapid development of society and economy has led to the problems of resource shortage and environmental pollution.Semiconductor photocatalysis technology has been widely used in environmental treatment,which has the characteristics of high efficiency,non-pollution and low cost.Bi VO₄ has been considered as a promising semiconductor photocatalytic material due to its stable structure,environment-friendly and moderate band gap.However,Bi VO₄ material has some shortcomings such as the easy recombination of photogenerated electron-hole pair and poor adsorption capacity,which limits its application in the field of photocatalysis.In order to increase the utilization rate of Bi VO₄ in visible light band and improve the photocatalytic performance,the morphology of Bi VO₄ is regulated by W and C doping to improve the photoelectron conversion performance.By X-ray diffraction,X-ray photoelectron spectroscopy,scanning electron microscope,transmission electron microscopy,ultraviolet spectrophotometry,fluorescence spectrophotometry,photoelectrochemistry properties and photocatalytic performance are characterized and analyzed,the relationship between the structure,morphology,and photocatalytic properties of the samples was systematically studied.In this paper,nanostructured monoclinic Bi VO₄（m-Bi VO₄）was synthesized by a surfactant free solvothermal method with glycerol aqueous solution as solvent.The results show that the m-Bi VO₄ sample have the characteristics of preferred orientation growth on{110}and{010}crystal planes and the morphology is homogeneous and dense polyhedron structure.On this basis,the lattice distortion of m-Bi VO₄ can be caused by W⁶⁺substituting for V⁵⁺in m-Bi VO₄ with different proportion of W doping.After doping,the samples change from smooth and uniform polyhedron to rough sheet leaf shape and then to irregular three-dimensional shape.W doping also improves the photocatalytic efficiency in some extent.Especially,when the doping ratio is 4%,the photocatalytic performance of leaf-like m-Bi VO₄ is improved to the maximum extent.This may be because an appropriate amount of W doping will change the morphology of the sample,increase its specific surface area and promote the separation of photogenerated electron-hole pairs.m-BiVO₄ photocatalysts with exposed{110}and{010}crystal planes were prepared by solvothermal method,and then doped with different molar ratios of C.Appropriate doping can not only enhance the growth of m-Bi VO₄ to{110}and{010}crystal planes,but also greatly change its morphology.With the increase of the doping ratio,the morphology of the samples gradually changes from uniform and dense block to irregular three-dimensional shape,which may be due to the lattice distortion of m-Bi VO₄ caused by C doping.Compared with the intrinsic m-Bi VO₄,the photocatalytic performance of doped m-Bi VO₄ is improved.When the C doping ratio is 5%,the absorption range of the sample becomes larger and the band gap decreases,enhancing the photocatalytic performance.In the experiment of MB degradation,the first-order kinetic rate constant is 1.29 times of that of intrinsic m-Bi VO₄.Moreover,the lamellar structure,high crystallinity and wide absorption of visible light may also be the reasons for the improvement of photocatalytic performance.