Hydrothermal preparation of nanosized brookite powders

Titania powders in pure brookite form were synthesized by hydrothermal trea tment of titanium(IV) salt solutions. Two kinds of starting materials, tita nium sulfate and titanium tetrachloride, were used in the hydrothermal reac tions. The effects of preparation conditions on the polymorphous form and m orphology of the titanium dioxide powders were studied. These conditions in cluded precursor species, precursor pretreatment, pH, and reaction temperat ure. The conditions that lead to brookite formation versus other phases, su ch as anatase and rutile, are generalized. The morphologic differences of t he three polymorphous powders are shown.