Oriented nanostructured titanates array from low concentration alkaline solution via hydrothermal process

Na ₂Ti ₂O ₅·H ₂O nanowire/nanobelt array and other nanostructures were hydrothermally prepared on Ti substrate in low concentration NaOH solution (>5 mol/L). Then the Na ₂Ti ₂O ₅H ₂O nanostructures were converted to H ₂Ti ₂O ₅ · H ₂O through an ion-exchange process and finally to TiO ₂ anatase by calcination at 450 °C without changing their nanostructures. The morphology of the prepared Na ₂Ti ₂O ₅·H ₂O nanostructures could be controlled by varying the experimental parameters such as hydrothermal temperature and alkaline solution. The formation mechanism of the nanoarray was also discussed.