Synthesis and characterization of titanate nanotubes and nanowires in a revolving autoclave

One-dimensional titanate nanotubes and nanowires were synthesized by hydrothermally treating TiO₂ nanoparticles (P25) with an aqueous NaOH solution in a revolving autoclave. The effect of the reaction temperature and time on the morphology and crystal structure of titanate nanomaterials was systematically studied. When the hydrothermal treatment was carried out in a revolving autoclave, nanotubes with Na_xH_1-xTi _2-x/4?_x/4O₄×H₂O crystal structure were obtained and favor to self-assemble in shape of clusters and bundles, and nanotube bundles tended to transform into nanowires with the crystal structure transforming into Na_xH_2-xTi ₃O₇ within 48 h at a hydrothermal temperature higher than 130 °C. Based on the experimental results, a possible mechanism for the formation of titanate nanotube by wrapping of nanosheets and nanowires formed via the cooperation of oriented attachment and Ostwald ripening was proposed.