Preparation Of Ga₂O₃/ZnO/WO₃ Composite Nanofibers By Electrospinning And Their Photocatalytic Properties

Semiconductor photocatalysis technology is an environmentally friendly and efficient emerging technology.This method can use sunlight as a driving force to quickly decompose organic pollutants in water bodies.Because WO₃ and ZnO have a relatively narrow band gap,ZnO and WO₃ as photocatalysts can absorb sunlight and participate in photocatalytic degradation reactions.Ga₂O₃,as a wide-bandgap semiconductor material(Eg=4.9 e V),can only excite the photocatalytic activity of Ga₂O₃ under the irradiation of short-wavelength deep ultraviolet light,and the photogenerated electrons excited to the conduction band have extremely strong oxidation ability,the holes generated on the valence band have a strong reducing ability.In this experiment,Ga₂O₃ loaded ZnO/WO₃ composite nanofibers with double heterostructures were prepared by electrospinning.Ga₂O₃/ZnO/WO₃ composite nanofibers have strong photocatalytic activity and high responsivity under ultraviolet-visible light irradiation.The research content is as follows:1.Electrospinning was used to prepare WO₃ nanofibers,ZnO/WO₃ composite nanofibers and Ga₂O₃/ZnO/WO₃ composite nanofibers.Using 200mg/L Rh B solution as the degradation substrate,after 120 min of photocatalytic reaction,the degradation efficiencies of WO₃,ZnO/WO₃ and Ga₂O₃/ZnO/WO₃ on Rh B dyes were measured to be 57.5%,96.9%and 98.4%respectively,which shows that Ga₂O₃/ZnO/WO₃composite nanofibers have the strongest photocatalytic activity,followed by ZnO/WO₃composite nanofibers,and WO₃ nanofibers have the weakest photocatalytic activity.By preparing a double heterostructure compound semiconductor material,the migration of photogenerated carriers can be effectively promoted,so that more photogenerated electrons and holes can participate in the redox reaction.2.In order to further study the properties of Ga₂O₃/ZnO/WO₃ composite nanofibers,we prepared samples calcined at different temperatures of 500?,600?,and 700?.The results showed that the Ga₂O₃/ZnO/WO₃ calcined at 600?Composite nanofibers have the most complete crystal morphology and the highest photocatalytic activity.Using SEM,XRD,EDS,XPS and PL spectra as characterization methods,the element composition,crystal structure,surface morphology,chemical valence and luminescence properties of Ga₂O₃/ZnO/WO₃ were measured.3.By studying the mechanism of Ga₂O₃/ZnO/WO₃ composite nanofibers participating in the photocatalytic degradation of Rh B,according to the theory of energy band matching,the transition of photogenerated electrons in the valence bands of Ga₂O₃,ZnO and WO₃ is excited under ultraviolet-visible light irradiation.Under the action of the built-in electric field force,the photogenerated electron e^-after the transition can be effectively transferred through the heterojunction formed between the three semiconductors,and finally a large amount of e^-is accumulated in the conduction band of WO₃,and a large amount of h⁺is accumulated in the valence band of ZnO.Therefore,this method realizes the effective separation of electron-hole pairs and successfully suppresses the recombination of carriers.