Preparation Of TiO₂/SiO₂Composite Material

TiO₂is an important semiconductive photocatalytic material. There is a promisingapplication to degrade organic material, photocatalytic activity and treat polluted water.However, when nanocrystalline TiO₂is prone to agglomerate, its excellent opticaltransmittance, high refractive index and chemical stability will decrease. So it is verynecessary to modify the surface of c particles.Nanosized pure SiO₂particles were prepared by hydrolysis of tetraethyl orthosilicate（TEOS） in TX-100/cyclohexane/isobutyl alcohol/water. Nano-composite particles withCore-shell structure had been synthesized by assembling of sodiym lauryl sulfate （SDS） andTiO₂nanoparticles onto nanosized SiO₂particles and finally removing the surfactant bycalcination. The effects of various factors, such as the molar ratio of H2O and Tx-100,content of SiO₂and calcination temperature, dispersing agent on the content of the anatasephase TiO₂were investigated and the process conditions were determined. In addition, it wassearched that nano-composite particles decomposed methyl orange and was supplied inpainting. The framework vibration bands of untreated and treated nano-titanium particleswere characterized by FTIR. Ingredient and structure of nano-composite particles can beanalyzed by SDTA and TGA. The dispersion of nano-SiO₂and nano-composite particles andthe size of nano-SiO₂were observed by TEM. The percentage of TiO₂-anatase was analysedby X-ray quantitative analysis method.The results show that the preparation of SiO₂/TiO₂nano-composite particles wasobtained by self-assembly technique in microemulsion. The diameter of TiO₂particles isabout5nm, which was determined from the result of TEM. As a result, the shell-corenanoparticles can obtain the more anatase phase TiO₂when the molar ratio [H2O]/[Tx-100],content of SiO₂and calcination temperature are2,10%and800oC, respectively. In certainsense, Nano-composite particles with Core-shell structure are very useful for strengthening photocatalytic activity of particles since the SiO₂can suppress the TiO₂growth andincorporation, which would improve the content of anatase phase TiO₂.