Alkali metal ion assisted synthesis of faceted anatase TiO2

Abstract

This work reports on a simple hydrothermal method for tuning the shape and exposed face of TiO2 nanocrystal by using sodium titanate as a precursor in the presence of different alkali metal ion salts. The {101}-exposed anatase TiO2 was synthesized in lithium salt solution. The formation of anatase TiO2 with exposed high-index {301} facet, obtained in the presence of sodium ions, has never before been reported upon. When the reaction proceeded in potassium salt solution, the obtained anatase TiO2 with a high aspect ratio was elongated in the < 001 > direction. Anatase TiO2 with a high aspect ratio was obtained in hydrothermal process in the presence of low charge density high atomic number alkali metal ions, which were not easily absorbed by the {001} planes of anatase, so the growth along this direction was not restrained. The photodegradation of methylene blue, assisted by anatase TiO2 with various exposed faces reveals that the photoactivity of anatase {101} planes is larger than that of {301} planes.