Contribution of Chemical Methods to the Study of Nanostructure of Ultrafine and Amorphous Materials

Controlling the hydrolysis conditions of the solution TiOSO4•xH2SO4•yH2O, the h-TiO2 and A-TiO2 single phases were prepared in amorphous/crystalline state. With scanty structural and electron microscopy data, the unique capability of differential dissolution method was used to perform quantitative phase analysis of the samples and identify phases where two from them (TiO)(HSO4)0.4(OH)and TiO(OH)2 were found to be amorphous. New results were obtained that the amorphous TiO(OH)2 is transformed to ~ 5-nm crystallites TiO2-x•0.95H2O which then turned into ~ 3-nm crystallites TiO2•0.25H2O when drying the gels at 90°C. New structural models for the crystallites were proposed explaining differences in their chemical and thermal characteristics.