Hydrothermal Treatment Duration Effect on the Transformation of Titanate Nanotubes into Nanoribbons

Abstract

Titanate nanotubes and nanoribbons have been synthesized hydrothermally using commercial anatase nanopowder (particle size ≈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 °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 °C) for different durations revealed the transformation of the nanotubes i...