Utilizing Polystyrene Microspheres as Confined Space to Help TiO2 Nanocrystals Formation with Assistance of Supercritical CO2

Titania nanocrystals were prepared by a particular way: first, supercritical CO2 (SC CO2) carried precursor tetrabutyl titanate (TBT) into the confined space of polystyrene (PS) microspheres; second, hydrolysis of TBT was controlled by the confined space of PS microspheres, which had a restraining effect on the hydrolysis rate of TBT; finally, TiO2 nanocrystals were obtained by calcining PS@TiO, composite microspheres. The products obtained after hydrolysis and calcination, that is, PS@TiO2 Composite microspheres and the finally obtained TiO2 nanocrystals, were characterized by transmission electron microscope and scanning electron microscope, respectively. Further high-resolution transmission electron microscopy and X-ray diffraction (XRD) indicated that the obtained TiO2 nanocrystals had fine crystalline structure. Additionally, the XRD pattern verified the presence of anatase and rutile in TiO2. The nucleation mechanism of TiO2 nanocrystals in the confined space of PS microspheres was also proposed.