Preparation of titania-zirconia composite aerogel material by sol-gel combined with supercritical fluid drying

Ultra-fine titania-zirconia composite aerogel materials have been prepared by supercritical drying of alcogels formed in sol-gel process by using cheap and convenient Ti(SO4)(2) and ZrOCl2 as the Ti and Zr sources, respectively. The effect of zirconia content on the textual and structural properties of the resulting materials was investigated by means of nitrogen adsorption-desorption, X-ray diffraction (XRD), TGA, laser Raman and transmission electron microscopy (TEM). The experiments indicated that the titania-zirconia composite calcined at 673 K demonstrated high specific surface area (387 m(2)/g) and mesoporous texture in the case where the percentage of each component in the specimen is 50%. Moreover, the XRD and Raman analysis showed that the Zr-containing compound is TiZrO4 when the temperature is increased to 1073 K. However, the surface area still remained as high as 95 m(2)/g. Therefore, we would conclude that doping of zirconia into titania structure with the formation of TiZrO4 could increase the mesoporosity, and would lead to the composite materials with high textual and thermal stability. (C) 2004 Elsevier B.V. All rights reserved.