The Effect of Temperature and Time on the Formation of TiO<sub>2</sub> (B) Nanowires via Hydrothermal Method

Abstract

TiO2(B) nanowires were prepared at 170 °C, 200 °C and 220 °C 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 °C. All samples were calcined in air at 400 °C 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 TiO2phase composition and its morphology. For 24 h hydrothermal synthesis, at low temperature of 170 °C, anatase TiO2nanoparticles were formed, while at higher temperature of 200 and 220 °C, TiO2(B) nanowires with averaged diameter of 49 nm and several micrometers in length were produced. Interestingly at 170 °C, by increasing reaction time to 72 h, anatase TiO2nanoparticles were completely transformed to TiO2(B) nanowires with averaged diameter of 74 nm and 2-4 micrometers in length.