Preparation And Characterization Of TiO₂-SiO₂Shell-core Pholocatalyst

With global population growth and economy development, photocatalyticoxidation has attracted wide attention on the environmental protection. Therefore,the development of photocatalysts has become one of the most popular researchsubjects in the world. TiO2-SiO2shell-core photocatalyst not only can improve thephotocatalytic activity of TiO2, but also can improve the dispersion and recycle ofthe catalyst. So it has attracted much attention due to its promising applications onthe purification of air, bactericidal action of water, and environmental photocatalyticdegradation of organic pollutant compounds and so on.In this thesis, silica microspheres synthesized by the stober method were usedas the cores. Then, TiO2-SiO2shell-core photocatalysts were prepared by twoapproaches, the charge absorption and reverse phase absorption, followed by theannealing under different temperatures. The phase constitution, microstructure,surface morphology and photocatalytic performance of the samples werecharacterized by scanning electron microscope (SEM), transmission electronmicroscopy (TEM), X-ray diffraction patterns (XRD) and Fourier transformedinfrared spectroscopy (FT-IR).Results indicate that the silica microspheres have advantages of smoothsurface、uniform size and larger dispersibility. The morphology of the TiO2-SiO2shell-core photocatalysts prepared by the method of charge absorption are affectedby amount of tetrabutyl titanate (TBOT) and pH value. When the molar ratio oftitanium and silicon is1:1, pH is2, the morphology of the samples is the best. Themorphology of the TiO2-SiO2shell-core photocatalysts prepared by the method ofphase absorption are also affected by the amount of TBOT. When it is0.004g mL-1,the coating thickness is about35nm, the morphology and the dispersibility of the samples is the best. By analyzing the XRD patterns of the samples, it is found thatthe phase transition temperature of the TiO2is increased because of the existence ofTiO/Si interface. The photocatalytic performance of the TiO2-SiO2shell-corephotocatalyst was investigated by the degradation rate of the methyl orange. Whenthe molar ratio of titanium and silicon is1:1, pH is2, the photocatalytic performanceof the samples prepared by the method of charge absorption is the best. The samplesprepared by the phase adsorption showed a poor photocatalytic performance.