Sonication–hydrothermal combination technique for the synthesis of titanate nanotubes from commercially available precursors

Titanate nanotubes with inner diameters of 2–6 nm, outer diameters of 5–10 nm and lengths up to 600 nm were fabricated by directly using commercial TiO2 powders as the precursors via sonication–hydrothermal combination approach. The formation processes during sonication treatment under different sonication powers and times and hydrothermal treatment were studied by scanning electron microscope (SEM) and transmission electron microscope (TEM) characterization. The chemical composition of the titanate nanotubes was determined in terms of X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) analysis. The influence of the particle size of the precursors on the formation processes was also examined. The tubular structure of the titanate nanotubes can be remained at the calcination temperature ≤450 °C, but was completely destroyed at high calcination temperature 600 °C.