Synthesis and Characterization of Surface-Protected Nanocrystalline Titania Particles

Monodisperse nonaggregated nanoparticles of titania are obtained through hydrolysis at 60 °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; 13 C, 17 O, and 1 H NMR and in solid state by X-ray diffraction, transmission electron microscopy (TEM), FTIR, thermogravimetry−dynamic thermal analysis (TG−DTA), 13 C cross-polarization−magic angle spinning (CP−MAS) 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.