Influence of solution concentration on the hydrothermal preparation of titania crystallites

Abstract

Nano/micro-sized titania powders were prepared by a hydrothermal method using an aqueous solution of TiCl4 as precursor. The influence of the concentration of the aqueous TiCl4 solution on the formation, phase, morphology, and grain size of the products was investigated at various reaction temperatures and times. Increasing the concentration of TiCl4 favored the formation of rutile type TiO2. When [TiCl4] < 0.5 mol dm−3, the products were a mixture of rutile type and anatase type powders, the percentage of rutile type powders in all crystalline products varied with reaction time. When [TiCl4] = 0.5 mol dm−3, the product was a pure rutile type powder. The powder size was related to the concentration based on the nucleation and growth theory of supersaturated solutions. A growth unit model was proposed to explain the phase formation.