Preparation Of Core-shell SiO 2 @TiO 2 Composite Nanospheres And Study On The Effect Of Annealing Time On Photocatalytic Performance

The core-shell nanocomposite is a new kind of composite functional material,which has attracted much attention due to its special structure and unique properties.The composite material is coated with a nanomaterial as a core,with another nanomaterial shell,by coating the shell material on a nuclear material by physical or chemical forces.The special feature of this material is that it can combine the advantages of two or more materials into one.Therefore,it is widely used in the field of functional materials.The results show that SiO₂ @ TiO₂ core-shell nanocomposites exhibit excellent performance in many fields,such as photocatalysis,antibacterial and cleaning,and have significant application value in other disciplines.In this paper,SiO₂ @ TiO₂ core-shell nanocomposites were successfully synthesized by gel-sol method,and annealed at 100 °C for different time.The microstructure and properties of the prepared silica nanoparticles were characterized by scanning electron microscopy,transmission electron microscopy,X-ray diffraction,Fourier transform infrared spectroscopy,UV-Vis spectrophotometer and multifunctional photoelectron spectroscopy.The size,morphology,crystal structure,absorption spectroscopy and chemical composition of TiO₂ nanoparticles were characterized.And the photocatalytic degradation of methylene blue solution was studied.In this study,silica nanoparticles were prepared by modified Stober method.The effects of the amount of ammonia and ethyl orthosilicate on the size of synthetic silica nanoparticles were studied.The surface of the prepared silica nanoparticles was rounded,the morphology was good and the water dispersibility was excellent.The silica nanoparticles microspheres were modified with silane coupling agent,and the titanium dioxide nanoparticles were successfully coated on the surface of the functionalized silica nanoparticles microspheres with titanium tetrabutyl titanate as the titanium source to form SiO₂@TiO₂ Composite nanoparticle microspheres.The microspheres of SiO₂@TiO₂ composite nanoparticles were annealed at 100 for different time.The synthetic SiO₂@TiO₂ composite nanoparticles prepared on the surface of the study have uniform particle size,good water solubility,good crystal structure,no obvious agglomeration,and titanium dioxide is anatase.The photocatalytic degradation of methylene blue solution was studied by analyzing the samples with different annealing times.The optimum annealing time was between 48-72 hours,and the photocatalytic effect of SiO₂@TiO₂ composite nanoparticles was the best.