Preparation,Modification And Photocatalytic Properties Of TiO₂-SBA-15

Semiconductor photocatalytic technology has been widely used in wastewater treatment systems because of its advantages such as fast reaction speed and no secondary pollution.Among them,TiO₂ has become a research hotspot due to its good stability,non-toxicity,high catalytic activity and strong anti-oxidation ability.Nevertheless,the applications of pure TiO₂ are limited,the small particles are difficult to recover by filtration or centrifugation after the reaction;the particles will agglomerate resulting in a decreased photocatalytic activity;the rapid recombination rate of the photogenerated electron-hole pairs limited its response of the UV-light.With the rapid development of industrialization and agriculture,water pollution has gradually attracted people’s attention.In particular,some organic pollutants such as phenols,which are difficult to be degraded.Therefore,how to efficiently and economically degrade organic pollutants in water is in the imminent.In this paper,TiO₂-SBA-15 nanocomposites was prepared by one step hydrothermal method,by using the TiOSO₄·H₂SO₄·xH₂O and Na₂SiO₃·9H₂O as titania and silica source respectively,P123 as a template.In order to increase the utilization of UV light,La and Ag nanoparticles were used to modify TiO₂-SBA-15.The photocatalytic performance and stability of the composite oxides were studied by photodegradation of phenol as a probe.The paper is divided into five chapters,as follows:In the first chapter,we summarized the catalytic mechanism and research progress of TiO₂ photocatalyst,reviewed the preparation and modification methods of TiO₂,introduced the research progress of SBA-15 supported TiO₂ photocatalyst.based on the disadvantages of titanium dioxide,We proposed research significance and research content.In the second chapter,we describes the reagents and instruments used in the experiment,preparation method,modification method,photocatalytic performance test and material characterization method of the TiO₂-SBA-15.The third chapter mainly introduces the preparation method of TiO₂-SBA-15compositeoxide.Highlyorderedmesoporous TiO₂-SBA-15nanocompositesweresynthesizedbya sol-gel-hydrothermal treatment using low-cost inorganic feedstock such as titanium oxysulfate and sodium metasilicate as precursors,followed sequentially by calcination at 600°C.All the catalysts were characterized by X-ray diffraction（XRD）,Small Angle X-ray Scattering（SAXS）,N₂adsorption–desorption,high resolution transmission electron microscopy（HRTEM）and fourier transform infrared spectroscopy（FT-IR）.The photocatalytic performance of the obtained TiO₂-SBA-15 nanocomposites was evaluated for the degradation of phenol under UV irradiation.Among the anatase TiO₂-SBA-15 nanocomposites,TS1（Ti/Si molar ratio 1:1）maintained an ordered mesoporous structure with a specific surface area of 357 m²/g,in which TiO₂ nanocrystals with distorted lattice and reduced interplanar space（d（101）=0.328 nm）.Due to the Si cations could diffused into the crystal lattice of TiO₂.As a result,TS1 exhibited a much higher photocatalytic activity for phenol degradation in comparison with the other catalysts,highlighting its potential application in photodegradation of phenolic wastewater.The fourth chapter is mainly based on the synthesis of TS1,La and Ag elements were used to modify TS1.The effect of different doping amount on the photocatalytic performance was compared.The FTIR,XRD,BET,and SEM were used to explore the structure changes of TiO₂/SBA-15 before and after modification.The photocatalytic performance of the modified TiO₂/SBA-15 was determined by degrading the phenol aqueous solutions with different initial concentrations.The results showed that when the doping amount was 0.1%,the phenol concentration was 50 mg/L,and the amount of catalyst was 1g/L,the degradation effect was the best.Moreover,the photocatalytic effect of the rare earth metal doped composite is better than that of noble metal silver.The fifth chapter summarizes the research,and looks forward to the development of photocatalytic materials and technology.