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 °C. Characterization of the TiO2 powder consisted of TEM, XRD and EDS methods.