Hydrothermal treatment duration effect on the transformation of titanate nanotubes into nanoribbons

Titanate nanotubes and nanoribbons have been synthesized hydrothermally using commercial anatase nanopowder (particle size approximate to 50-400 nm) and NaOH. The samples were characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (TEM-SAED), and X-ray diffraction (XRD). It has been found that the hydrothermal temperature and the treatment duration have a strong effect on the morphology control of the resulting products. At a fixed temperature of 180 degrees C, the morphology of the products changes with the hydrothermal duration (5-72 h). Hollow nanotubes with an outer diameter of about 10 nm were formed at treatment durations between 5 and 20 h. Bundles of nanoribbons with widths ranging from 50 to 500 nm and lengths up to several tens of micrometers were produced at a treatment duration of 72 h. Experimental results on samples treated at different temperatures (135-195 degrees C) for different durations revealed the transformation of the nanotubes into nanoribbons after specific treatment duration at any selected temperature, so we predict that optimizing the hydrothermal temperature and treatment duration may lead to a better control of the product morphology.