Abstract

A new approach for direct synthesis of well-shaped pure rutile titania nanocrystals by hydrothermal synthesis is reported. The synthesis of the 20 nm rutile particles from titanium isopropoxide and pH 0.5 nitric acid is achieved by vigorous stirring of the solution during the hydrothermal treatment. The significant effect of the stirring and long aging control experiments suggest that, at this composition, most of the condensation to TiO₂ occurs during the autoclaving step. The large colloid size distribution and the formation of the anatase structure in the absence of stirring are attributed to the inhomogeneity developed in the solution under the extreme conditions of the hydrothermal process. The significance of the new method is the elimination of the commonly used mineralizers that can induce impurities into the nanocrystals, in addition to the improved colloid shape in comparison with standard procedures.