Synthesis and Characterization of Thermally Stable Nanotubular TiO₂ and Its Photocatalytic Activity

Hydrogen titanate nanotubes obtained by hydrothermal synthesis are treated with sol containing titanium. The products are characterized with transmission electron microscopy, X-ray diffraction, thermal gravimetric analysis, and Raman spectroscopy. Their photocatalytic performance is evaluated by the photocatalytic degradation rates of methyl orange in aqueous solution under UV−vis light irradiation. The results reveal that the treated nanotubes are more thermally stable and exhibit better photocatalytic performance than primary nanotubes. The treated nanotubes can keep a tubular structure when calcined at 400 °C. However, their precursors collapse when they are calcined only at 300 °C. The more thermally stable new functional TiO 2 nanotubes can be prepared by using sol containing other elements instead of sol containing Ti in the future.