TiO₂ aerogel prepared by ambient pressure drying

Monolithic TiO₂ aerogels have been prepared by sol-gel method and subsequent process such as solvent replacement with ambient pressure drying using titanate tetrabutoxide, formamide and acetic acid as raw material. The influences of organic ligand on the structure of aerogels were investigated. The microstructure and properties of samples were characterized by means of XRD, BET, SEM, EDS and DSC-TG. The results indicate that when the mole ratio of organic ligand to titanate tetrabutoxide is 0.9, the property of prepared TiO₂ aerogel is the best, with the apparent density of 0.25 g·cm^-3, the specific surface area of 716.5 m²·g^-1, and the average pore size of 19.1 nm. After calcined at 850℃ for 2 h in air, the sample has high photocatalytic activity, while it's specific surface area reduces to 122.4 m²·g^-1 and average pore size increases to 23.4 nm. After calcined at 1000℃, anatase is still the main crystalling phase, and shows low photocatalytic activity. The apparent density of TiO₂ aerogel (not using organic ligand) is 0.57 g·cm^-3, and it's specific surface area is 482.2 m²·g^-1. TiO₂ aerogels prepared using organic ligand present less dense and higher specific surface area.