Structure analysis of titanate nanorods by automated electron diffraction tomography

Abstract

A hitherto unknown phase of sodium titanate, NaTi3O6(OH)·2H2O, was identified as the intermediate species in the synthesis of TiO2 nanorods. This new phase, prepared as nanorods, was investigated by electron diffraction, X-ray powder diffraction, thermogravimetric analysis and high-resolution transmission electron microscopy. The structure was determined ab initio using electron diffraction data collected by the recently developed automated diffraction tomography technique. NaTi3O6(OH)·2H2O crystallizes in the monoclinic space group C2/m. Corrugated layers of corner- and edge-sharing distorted TiO6 octahedra are intercalated with Na+ and water of crystallization. The nanorods are typically affected by pervasive defects, such as mutual layer shifts, that produce diffraction streaks along c*. In addition, edge dislocations were observed in HRTEM images.