Morphology tuning in nontemplated solvothermal synthesis of titania nanoparticles

Nanoparticles and nanocrystalline particles of pure anatase titania (TiO₂) were synthesized by solvothermal processing of TiCl₄ ethanol and isopropanol solutions at 120 to 200 °C. This one-step and nonsurfactant approach is versatile and the morphology tuning can be achieved by manipulating the growth kinetics. Dispersed nanocrystals of spherical, cubic, and acicular shapes and hollow spherical and core-shell structured micrometer-sized particles were obtained under different experimental conditions. The obtained hollow spherical- and core-shell–structured particles have an average diameter of 700 nm to 1.0 μm, with an average crystallite size of 5 to 16 nm. The dependence of nucleation/crystal growth and morphology development on solvothermal medium, reaction temperature, and reactant concentration was investigated. The reaction mechanism was then suggested and tentatively discussed from coordination and solution chemistry.