Fine size-regulation of nanocrystalline anatase-TiO2via sol-gel synthesis and subsequent phase transformation by calcinationElectronic supplementary information (ESI) available. See DOI: 10.1039/c3nj41170b

Nanocrystalline TiO 2 particles were prepared via the sol-gel process. The particle size and nanostructure of the TiO 2 sol were controlled through the ageing process accompanied by hydrolysis-polycondensation. The resultant TiO 2 particles were analysed by BET, HR-TEM, PSA, TGA, turbidity, XRD, and zeta potential analyses. The TiO 2 size increased with increasing ageing time and reaction temperature. A phase transformation from anatase to rutile occurred with heat treatment at 500 °C. The phase transformation is strongly influenced by the primary particle sizes of TiO 2 , which were characterised via XRD and Raman spectroscopic analyses. The particle sizes and physicochemical properties can be controlled through the ageing conditions such as time and reaction temperature. The phase transformation is influenced by the particle sizes.