Studies On Structural Regulation Of Core-shell And Hollow TiO₂ For Photocatalytic Phenol Degradation

TiO₂ based semiconductor catalysts have attracted more and more attention due to their unique high photocatalytic activity,high chemical stability,complete mineralization of organic compounds and no secondary pollution.By regulating the microstructure of TiO2 nanomaterials,their photocatalytic reactivity can be further improved.In this paper,monodisperse SiO₂ nanospheres were synthesized by St?ber method,and was used the core to synthesize core-shell structure SiO₂@TiO₂ by sol-gel method,then SiO2@TiO2@Ag composite catalysts was synthesized by Ag modified under ultraviolet radiation.RF microspheres were synthesized by expanding St?ber method,and hollow TiO₂was synthesized by sol-gel and two-step calcination with RF microspheres as cores.Adjusting the preparation parameters,the shell thickness of hollow TiO₂ was regulated,and H-TiO₂nanomaterials with excellent properties.And then H-TiO2@Ag composite catalysts was synthesized by Ag modified under ultraviolet radiation.X-ray diffraction?XRD?,N₂ adsorption isotherms?BET?,Fourier transform infrared spectroscopy?FT-IR?,scanning electron microscope?SEM?,transmission electron microscopy?TEM?,thermogravimetric?TG-DTA?,element analysis?EDS and XPS?were used to characterize the catalysts.Phenol were used as target degradants to investigate the photocatalytic activity of composite catalysts,and the degradation mechanism and photocatalytic mechanism of phenol were investigated.The results showed that:?1?Mono-dispersed core-shell SiO₂@TiO₂ nanomaterials were prepared by sol-gel method and the process parameters were adjusted having a large specific surface area?35.79m²/g?,which was used for photocatalytic phenol degradation,the phenol degradation rate reached 98%after 180min of ultraviolet radiation.The photocatalytic degradation efficiency of phenol was improved by 33.3%after Ag modified.?2?Expand St?ber method to synthesize RF microspheres,RF microspheres?450nm?with particle uniformity and good dispersion were prepared by adjusting the amount of ammonia.The influence of the amount of ammonia on the microstructure and particle size of RF microspheres was discussed;?3?hollow TiO2 prepared by sol-gel and two-step calcination method,complete anatase TiO₂ crystal,specific surface area up to 30.20 m²/g.The amount of ammonia was adjusted to regulate the thickness of hollow TiO₂ shell from 20 nm to 160 nm.When the amount of ammonia was 0.30 ml,the thickness of hollow TiO2 shell to 80 nm,and photocatalytic effect was the best,and the phenol was degraded to 98%at 150minof ultraviolet radiation.Moreover,adjusting the amount of TBOT to regulate the preparation process of hollow TiO2,it is found that excessive amount of TBOT will make the core-shell material agglomerate,which is disadvantageous to the formation of monodisperse nanomaterials.?4?the prepared hollow structure TiO2 was supported by Ag,degraded to 98%of phenol for 90 min ultraviolet radiation,and the photocatalytic effect was improved by 40%,among which,the photocatalytic effect was the best when the load was 6%.