Structural transformation from NaHTi_3O_7 nanotube to Na_2Ti_6O_(13) nanorod

摘要

NaHTi_3O_7 nanotubes were synthesized by the hydrothermal method. Temperature effects of the nanotubes are examined by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), x-ray diffraction (XRD), thermal gravity analysis (TGA), and Raman spectroscopy. With increasing the annealing temperature NaHTi_3O_7 nanotubes undergo a slight degradation and more degradation of the tubular shape, respectively at 300 and 500 ℃, and finally become complete Na_2Ti_6O_(13) nanorods after annealing at 700 ℃ for 1 hour. The structure characters and lattice dynamics of both nanotubes and nanorods were investigated. The transformation mechanism between NaHTi_3O_7 nanotubes and Na_2Ti_6O_(13) nanorods is discussed to be attributed to release of the structural water in the interlayer space during self-oriented attachments, and to take more stable configuration with low energy.