Study On Preparation And Photocatalytic Properties Of Composite Microspheres

Semiconductor titania?TiO₂?and Graphitic carbon nitride?g-C₃N₄?photocatalytic materials have great potential in the field of environmental pollution,but the larger band gap?E_g=3.2 eV?of anatase TiO₂ is serious limiting its use of visible light,which seriously hindered the scope of its practical application.Therefore,widening the absorption range of TiO₂ in the visible light is an important way to improve the photocatalytic activity.g-C₃N₄ is a non-metallic organic polymer semiconductor,because of its good thermal stability,chemical stability and appropriate band gap,it is suitable for chemical modification,so in the use of solar energy has great potential for development.However,it also has some drawbacks,such as high photogenerated electron and hole recombination rate and low specific surface area,resulting in lower photocatalytic activity.Therefore,To improve the photocatalytic activity of the catalyst key to maximize the inhibition of photo-generated electrons and hole recombination rate,and increase its specific surface area,resulting in high activity of the photocatalyst.In this paper,semiconductor TiO₂ and g-C₃N₄ were used as the research object,and several microspheres composites were prepared by the relationship between the properties of the two materials.The photocatalytic activity is greatly enhanced by the preparation of microspheres morphology of TiO₂ or g-C₃N₄ increasing its specific surface area,and then modified formation of heterogeneous or double charge transfer of TiO₂ or g-C₃N₄.The specific contents of the paper are as follows:?1?we successfully prepared TiO₂@Ag/g-C₃N₄ ternary composite photocatalyst.The as-prepared sample was characterized by FT-IR,XRD,SEM,DRS and PL characterization methods for the sample of the structure,crystal phase,morphology and optical properties were analyzed.The photocatalytic activity of MB was tested under visible light?xenon lamp?,The results showed that the degradation rate of97.3%when 20 mg the catalyst of the initial concentration was 20 mg/L MB after 120min irradiation,and the possible reaction mechanism was analyzed.?2?The g-C₃N₄ microspheres were prepared by template method,?-FeO?OH?was loading on the surface of the microspheres,and the g-C₃N₄/?-FeO?OH?composites were obtained.The structure and appearance were characterized by FT-IR,XRD,SEM,DRS and PL.The photocatalytic activity of photocatalytic degradation of methylene blue?MB?,methyl orange?MO?and rhodamine B?RhB?solution under simulated sunlight was investigated.We added 15 mg catalyst to carry out the photocatalytic experiment,then found that the degradation rates of MB,MO and RhB three dyes with the initial concentration of 30 mg/Lwere about 99%,100%and 99%after irradiated 120 min.?3?The monodisperse SiO₂ microspheres were prepared by hydrothermal method.The TiO₂ layer was coated with SiO₂ microspheres by sol-gel method.The Ag nanoparticles were deposited on the surface of the composite microspheres by interfacial deposition.Finally,SiO₂ layer was coated on SiO₂@TiO₂-Ag microspheres by surfactant method to obtain SiO₂@TiO₂-Ag@SiO₂ microspheres.It was found that the prepared Si O₂@TiO₂-Ag@SiO₂ microspheres had both photocatalytic degradation and flocculation,and the degradation rate of MB solution was 97%in visible light and could be caused by electrical neutralization with anionic dye MO Flocculation sedimentation,in a short time decolorization rate of 99.7%.The bifunctional nanospheres provide a new idea for the treatment of dye wastewater and broaden the scope of application of photocatalyst.