Green synthesis of TiO2 nanocrystals with improved photocatalytic activity by ionic-liquid assisted hydrothermal method.

Owing to potential industrial applications and fundamental significance, tailored synthesis of well-defined anatase TiO2 nanocrystals with exposed highly reactive {001} facets has stimulated great research interest. In this work, surface-fluorinated anatase TiO2 nanocrystals have been successfully prepared by using an ionic liquid (IL) assisted hydrothermal synthetic route. TiCl4 is used as precursor, and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim](+)[BF4](-)) as morphology-controlling agent. The anion of the IL plays a key role in controlling the crystallization process via a dissolution-recrystallization process. Compared with the benchmark material Degussa P25, the fluorinated anatase TiO2 nanocrystals exhibit superior photocatalytic activity.