Preparation of hexagonal prism anatase with high thermal stability from a HTiOF3 precursor

Abstract

Anatase hexagonal prism TiO₂ with high thermal stability was prepared through the decomposition of precursors (HTiOF₃). HTiOF₃ was firstly synthesized, using a solvothermal method, from n-octanol, tetrabutyl titanate and hydrofluoric acid. The obtained precipitates were then calcined at different temperatures (200–900 °C) for 2 h. The formation process of the hexagonal prism HTiOF₃ precursors included three steps: nuclei growth, dissolution–recrystallization and further growth. The morphologies of the precursors depended strongly on the reaction temperature and the amount of solvent. The precursors were transformed into TiO₂ after calcination and the effect of the calcination temperature on the morphology and phase composition of the hexagonal prism TiO₂ was investigated. The results indicated that the anatase hexagonal prism TiO₂ exhibited a rather high thermal stability, maintaining both the anatase structure and precursor shape up to 800 °C. The sample that was calcined at 550 °C exhibited a superior photocatalytic performance.