Preparation And Photocatalytic Proformance Of One-dimensional Tungsten-based Oxide Nanocomposites

In recent years,photocatalysis has become one of the internationally recognized effective methods to deal with environmental problems.This method is one of the important ways to solve the energy crisis and environmental problems by using solar energy to degrade organic pollutants through semiconductors,and it is low cost and pollution-free.The key of photocatalysis technology is the selection and preparation of suitable catalyst,so the development of catalyst determines the application prospect of this technology in the future.In this paper,a variety of tungsten-based oxide photocatalysts with one-dimensional nano-morphology are prepared by electrostatic spinning,and their photocatalytic properties were discussed.The main contents and conclusions are as follows:1.First,an ultrafine tungsten trioxide nanofiber photocatalyst is prepared by electrospinning.Then,Pt/WO₃ nanofiber photocatalytic composite with high visible light photocatalytic activity is synthesized by oil bath method.When the content of Pt particles is 1%,the degradation efficiency of Pt/WO₃ nanofibers to RhB dye reaches93.7%.The mechanism of Pt modification to enhance its photocatalytic performance is analyzed by a first-principles method based on DFT.Therefore,it is known that the Schottky barrier generated by the loading of the Pt particles effectively improves the transmission efficiency of the photo-generated carriers,and exhibits better photocatalytic performance than the WO₃.Through cyclic testing and characterization,it is proved that the prepared Pt/WO₃ nanofibers are an ideal photocatalyst for degrading organic dyes.2.ZnWO₄/WO₃ heterostructure nanotubes are prepared by electrospinning.Characterized,the nanotubes have a diameter of 200 nm and a wall thickness of 40 nm.The photocatalytic performance of the sample is discussed by degradation of 4-NP solution under visible light irradiation,and the degradation efficiency reaches 91.2%.The photocatalytic efficiency is nearly four times higher than that of pure WO₃nanofibers.In addition,the active groups that play a major role in the photocatalytic reaction are h⁺and·OH.Combined with DFT calculations,the electron transfer path in the photocatalytic process is explored.The conclusions are as follows:due to the heterostructure interface and the porous structure in the heterostructure,the transport of photogenerated carriers is promoted,and the transfer of electrons from ZnWO₄ to WO₃.The efficiency of electron hole pair separation is increased effectively,which is the main factor of improved photocatalytic performance.3.CoWO₄/ZnWO₄ porous heterostructure nanotubes are prepared by electrospinning.After morphological characterization,the nanotubes have a diameter of 150 nm and a wall thickness of 20 nm.The elemental composition and chemical valence of the heterostructure are analyzed by XPS and other methods.The photocatalytic performance of the sample is discussed by degradation of 4-NP solution under visible light irradiation,and the degradation efficiency reaches 90.3%.The conclusions are as follows:the porous structure formed in the calcination process provides more active sites for the photocatalysis process,which increases the contact surface between the photocatalyst and the degradation product,which is beneficial to improve the degradation of pollutants.In addition,it is found that the heterostructure has larger photocurrent density and smaller electron transfer internal resistance,which is beneficial to carrier transmission,suppresses the recombination of electron hole pairs,and improves the photocatalytic performance of the heterostructure.4.A monoclinic/hexagonal WO₃ phasejunction structure is prepared by hydrothermal method.The crystal structure and composition of the sample are analyzed by XRD.The morphology of structure is analyzed by SEM and TEM.The degradation of RhB solution is tested under visible light irradiation.The photocatalytic performance of monoclinic/hexagonal WO₃ photocatalyst is analyzed.The results show that the prepared monoclinic/hexagonal WO₃ phasejunctions have improved degradation performance compared to monoclinic and hexagonal single WO₃.The conclusions are as follows:through photocatalytic and photoelectric performance analyzing,it is known that the phasejunction can generate more carriers,and the smaller internal resistance is more favorable for carrier transport,and finally the photocatalytic performance is improved.In addition,the experimental method needs further improvement,but this idea provides a feasible idea for the development of photocatalyst.