Synthesis of nanotube from a layered H2Ti4O9 · H2O in a hydrothermal treatment using various titania sources

In this paper, the synthesis of tubular titania was carried out through a soft chemical hydrothermal reaction of TiO2 powders in NaOH or KOH aqueous solution systems. It was found that nanotubular products prepared in our studies were identified as H2Ti4O9·H2O by X-ray diffraction analysis with their morphology and crystallinity being dependent on synthetic conditions, i.e. reaction time and temperature of the hydrothermal process. The photocatalytic activity of nanotubular H2Ti4O9·H2O was evaluated in a decomposition test of HCHO at 298 K in an aqueous system using radiation with a mercury lamp. The morphology and yield of these nanotubular products were found to be dependent on the hydrothermal synthetic conditions.