Dominant Influence of the Surface on the Photoactivity of Shape-Controlled Anatase TiO2 Nanocrystals

摘要

Shape-controlled anatase TiO2 nanocrystals with large {001} facets are synthesized by a hydrothermal 30 method Using HF as a shape-controlling agent. The photoactivity of the TiO2, nanocrystals is evaluated from the photOclegradation rate of methylene blue in aqueous solution under UV irradiation. Here, we observe higher photoactivities for the TiO2 nanocrystals with a {001} ratio of close to 60%, which; is the shape in photoactivity. In addition, we observe that the photoactivity is further enhanced when the 01.1%ZoC tos. are treated in a dilute NaOH (HF) solution. and EPR analyses reveal that the etching in Solution can induce significant changes in the efects as well as in the surface morphology. We find that the enhanced photoactivity is closely related to the changes in surface defects, which favor the formation of surface O- species under ambient conditions.