Sequence of Events for the Formation of Titanate Nanotubes, Nanofibers, Nanowires, and Nanobelts

The formation of H₂Ti₃O₇ nanotubes, nanofibers, nanowires, and nanobelts via alkali hydrothermal synthesis was studied in detail by TEM and HRTEM. The effects of preparation parameters, such as reaction temperature, duration, and cooling process, on the morphologies of the products are clarified. A universal formation mechanism is proposed based on the growth, split, wrapping, and thickening of Na₂Ti₃O₇ nanointermediates, which links all kinds of morphologies observed for H₂Ti₃O₇ nanoentities.