Nanocomposite TiO2-SiO2 gel for UV absorption

Nano-sized particle TiO2-doped SiO2 gels have been synthesized for use as composites in which the UV absorption efficiency, the major factor for UV protection, can be enhanced. SiO2 gels having a mesoporous morphology have been synthesized via a sol-gel processing route using rice husk as the starting material and further treated using additions of TiO2 from two sources. The chemical purity of the SiO2 was measured by X-ray fluorescence analysis (XRF). Typical samples of pure TiO2, SiO2 and their composites were tested for surface characteristics using N-2-sorption (BET surface area). All the different compositions processed have been characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), and imaged using Scanning and Transmission Electron Microscopy (SEM, TEM). The UV absorption values which determine the degree of UV-protection, were measured and the results discussed. The concentration of TiO2 loading, the particle size, and the surface characteristics are shown to relate to the degree of UV absorption and the measured energy band gap of the composites. (C) 2011 Elsevier B.V. All rights reserved.