Effect of Calcination Temperature on the Structure, Crystallinity, and Photocatalytic Activity of Core-Shell SiO2@TiO2 and Mesoporous Hollow TiO2 Composites

Abstract

TiO2 and core–shell SiO2@TiO2 nanoparticles were synthesized by sol-gel process at different calcination temperatures. Mesoporous hollow TiO2 composites were prepared by etching SiO2 from SiO2@TiO2 nanoparticles with alkali solution. X-ray diffraction (XRD), Scanning electron microscope (SEM),Transmission electron microscope (TEM), and N2 adsorption–desorption isotherms, and Roman and Diffuse reflectance spectroscopy (DRS) were employed to characterize the synthesized materials. The effects of different calcination temperatures on the morphology, crystallinity, phase composition, and photocatalytic activity of the prepared materials were investigated in detail. It was found that the calcination temperature altered the phase structure, crystallinity, morphology, specific surface area, and porous structure. Additionally, it was verified that SiO2 could inhibit the transfer of TiO2 from anatase phase to rutile phase under high temperature calcination (850 °C). The hollow TiO2 calcined at 850 °C showed the highest photocatalytic efficiency of 97.5% for phenol degradation under UV irradiation.