Synthesis and characterization of surface-protected nanocrystalline titania particles

Monodisperse nonaggregated nanoparticles of titania are obtained through hydrolysis at 60 degrees C of titanium butoxide in the presence of acetylacetone and para-toluenesulfonic acid. After the particles are dried, the resulting xerosols can be dispersed without aggregation in water-alcoholic or alcoholic solutions at concentrations higher than 1 M. The characterizations of the nanoparticles were carried out in solution by using quasi-elastic light scattering (QELS); FTIR; C-13, O-17, and H-1 NMR and in solid state by X-ray diffraction, transmission electron microscopy (TEM), FTIR, thermogravimetry-dynamic thermal analysis (TCT-DTA), C-13 cross-polarization-magic angle spinning (CP-NIAS) NMR. The mean size of the anatase oxide core can be adjusted in the 1-5 nm range by a careful tuning of the synthetic conditions. The protection of these particles toward aggregation is ensured through the complexation of the surface by acetylacetonato ligands and through an adsorbed hybrid organic-inorganic layer made with acetylacetone, para-toluenesulfonic acid, and water.