Dissolution/recrystallization growth of titanate nanostructures by amorphous precursor

摘要

Understanding of growth mechanism is of technical importance for tailoring the size and morphology of titanate nanostructures. However, the growth mechanism of titanate nanostructures in alkali solution systems by using crystalline TiO2 remains debating currently. In the present work, the amorphous precursor of titanium hydroxide precipitates, a highly disordered raw material, was used as the precursor to prepare the titanate nanostructures under hydrothermal conditions. SEM and TEM results show that the morphology of the titanate nanostructures developed from nanoparticles to nanosheets and then the titanate nanowires with an interlayer spacing of 0.786 nm as the reaction time prolonged. XRD and Raman spectra results display that layered titanate nanostructure were formed. These phenomena are similar to that of the titanate nanostructures prepared by the TiO2 crystal in alkali solution systems. The findings provide direct evidence to strongly support that titanate nanostructures grow from dissolution/recrystallization process under hydrothermal process, allowing mediating the size and morphology of titanate nanostructures. Moreover, SEM and photocatalytic results implied that the washing process improved the photocatalytic activities, which had no effect on the overall morphology.