Influence of silica ratio on structural and optical properties of SiO_2/TiO_2 nanocomposites prepared by simple solid-phase reaction

摘要

TiO_2/SiO_2 (Ti-O-Si) nanocomposite were prepared by a simple solid-phase reaction under natural atmosphere at 500 °C after the incorporation of silica (SiO_2) nanoparticles, in TiO_2 with varying the percentage weight of silica in the mixture (20, 30 and 50%). X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the phase purity, particle size and morphology. UV-vis absorption spectroscopy and optical density measurements (DO) allowed us to investigate the optical properties of our samples and to determine some crucial parameters such as the band gap energy E_g and the optical density DO. By the same, the band gap energy E_g achieves higher values as well as the optical density decreases for all the used wavelengths. These observations results from the formation of the Ti-O-Si bond and the presence of amorphous silica around anatase, which would impede the growth of TiO_2 particles. The internal microstructure thus obtained will perform the stability of our composite allowing an enhancement of optical, electrical and catalytic features of TiO_2.