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.