Abstract
The titanium oxide aerogel as photocatalyst was prepared by supercritical carbon dioxide drying to remove solvent alcohol, followed by crack-free wetting gel synthesis of sol-gel method. Titanium alkoxide, 2-propanol, water, and HCl compositions were optimized to find the best molar ratio for the synthesis of crack-free aerogel. We also introduced dimethylformamide (DMF) as a drying control reagent into the synthesis of wetting gels. Wetting-gel cracks were inhibited quantity of the suitable HCl, and DMF concentration. The aging with high temperature and long aging time do not improve aerogel properties. The mass of consumed CO2, and CO2 flow rate are important parameter to prevent crack and shrink on the aerogel. The drying of wetting gel finished by using CO2 volume 10000 g-CO2/g-wetting gel during the weight of dried gel approached that of TiO2 aerogel. Preparation parameters such as drying procedure influence on aerogel properties revealed by means of X-ray diffraction, acetaldehyde decomposition profile, and transmission electron microscope. The x-ray diffraction analysis of calcinated aerogel identified as anatase phase of titanium oxide.
