Preparation And Properties Of Flower-like TiO₂ Hydrogenated And GQDs Composites

Titanium dioxide semiconductor photocatalyst have an good degradation ability to organic wastewater and will become a strategy for treating organic wastewater in the future.However,the original titanium dioxide only can use the energy of the UV region and has a high photogenerated electron-hole recombination rate,those limit its practical application.Photocatalytic propertie of TiO2 is closely related to those factor such as crystal structure,morphology,surface hydroxyl groups,crystal defects and so on,To explored the relation ship bteween those and composites properties,we have designed and carried out a series of experiments and work to obtain high performance hydrogenated flower-like TiO₂ and their graphene quantum dots composite.The research results are summarized as follows:?1?We prepared TiO₂ with flower-like micro/nanostructured and uniform size and good dispersibility by hydrothermal treatment under the condition of PVP surfactant.Whereafter,It was calcined to gain hydrogenated product under hydrogen atmosphere.We studied the effect of temperature and time on the final product.With the increase of temperature and time,the color of TiO₂ was changed from white to gry,and its light absorption performance in the visible region increased gradually.Subsequently,the performance test was carried out,the photocatalytic performance of the TiO₂ hydrogenated under visible light irradiation was significantly improved as compared with the TiO₂ unhydrogenated.Fluorescence spectra and photocurrent measurements indicate that hydrogenation enhances the separation of photogenerated electrons and holes.?2?A well-formed composite of micro/nanostructured TiO₂ and GQDs was prepared by simple hydrothermal method.The effection of GQDs content on the product was investigated.Its photocatalytic performance was tested under simulated sunlight illumination,followed by stability testing of the best performing sample,XRD.TEM.In addition,Raman and XPS were used to analyze phase and composition,performance and mechanism were analyzed by UV-Vis spectra,fluorescence spectra and transient photocurrent test.?3?We combined the above two effective strategies to prepare a composite material of gray flower-like micro/nanostructure TiO₂ and GQDs and effectively improve the photocatalytic performance.Suitable preparation conditions screened out with different GQDs addition conditions.Subsequently,the performance of a series of photocatalysts were tested by simulated sunlight,the test result show that the composites have excellent photocatalytic properties.These two strategies complement each other and have the function of superimposing and promoting each other,which can simultaneously improve light absorption performance and promote separate of photogeneration electron-hole pairs.