Preparation of TiO2 nanoparticles by supercritical carbon dioxide

Nano-sized titanium dioxide TiO2 powder was successfully prepared from its precursor titanium (IV) isopropoxide (TTIP) by a system comprising of supercritical fluids microemulsion and supercritical-drying method, in which TTIP reacted in reversed micelles formed by surfactant Zonyl FSJ employing a supercritical carbon dioxide system. The milky white product, collected from the bottom of the pressure cell turned into sol-gel after sitting in the air for 5 days. Amorphous TiO2 particles with particles size 2 - 7 nm can be obtained from the sol-gel by the supercritical-drying method. The amorphous TiO2 particles were converted to anatase phase by calcining at 500 degrees C. Characterization of the TiO2 powder consisted of TEM, XRD and EDS methods. (c) 2007 Elsevier B.V. All rights reserved.