The Effect of Temperature and Time on the Formation of TiO_2 (B) Nanowires via Hydrothermal Method

摘要

TiO_2 (B) nanowires were prepared at 170℃, 200 C and 220℃ for 24 h via hydrothermal synthesis to evaluate the effect of temperature on phase composition and morphologies. The effect of reaction time: 24 and 72 h on the formation was also studied at 170 ℃. All samples were calcined in air at 400 ℃ for 2 h. Phase identification was performed using X-ray diffraction (XRD) and morphologies was examined by a scanning electron microscope (SEM). It was found that hydrothermal temperature and time played an important role in defining TiO_2 phase composition and its morphology. For 24 h hydrothermal synthesis, at low temperature of 170 ℃, anatase TiO_2 nanoparticles were formed, while at higher temperature of 200 and 220 ℃, TiO_2 (B) nanowires with averaged diameter of 49 nm and several micrometers in length were produced. Interestingly at 170℃, by increasing reaction time to 72 h, anatase TiO_2 nanoparticles were completely transformed to TiO_2 (B) nanowires with averaged diameter of 74 nm and 2-4 micrometers in length.