Hydrothermal preparation and characterization of brookite-type TiO2 nanocrystallites

Titanium dioxide in brookite form was prepared by two different methods under hydrothermal condition. One method used titanium sulfate as precursor, while the other used titanium tetrachloride as precursor. The growth mechanism of titanium dioxide includes two reaction steps. The first reaction is the hydrolysis of titanium salt, in which polynuclear species of hydrous titania are formed. The second reaction represents the crystallizing reaction under hydrothermal condition, in which various polynuclear hydrous titania are combined together through dehydration reaction to form titanium dioxide crystals.