TiO2-impregnated SiO2 aerogels by alcohol supercritical drying with zeolite

摘要

Preparation of monolithic TiO2-impregnated SiO2 aerogels (SiO2-TiO2 aerogels) with controlled microstructure was investigated. Tetraisopropylorthotitanate-acetylacetone mixture was impregnated to micro structure-de signed silica alcogels and was decomposed during alcohol supercritical drying (SCD). The microstructure of these SiO2-TiO2 aerogels reflected that of the corresponding SiO2 aerogels. Anatase was detected by X-ray diffraction. Some of titanium elements were included in silica matrix, and the others existed as particles with 100-150 nm on the surface of the matrix. Titanium content was 25-34 at.% in SCD without zeolite, whereas SCD with zeolite increased it to over 40 at.% and decreased the amount of the particles on the surface. The SCD with zeolite was considered to prevent titanium components from being removed from the matrix with silica alcogel components. (C) 1998 Published by Elsevier Science B.V. All rights reserved. [References: 8]