Abstract: The fabrication of well defined hierarchical structures of anatase TiO₂ with a high percentage of reactive facets is of great importance and challenging. Hierarchically flower-like TiO₂ superstructures (HFTS) self-assembled from anatase TiO₂ nanosheets with exposed {001} facets (up to 87%) were synthesized by a simple alcohothermal strategy in a HF-H₂O-C₂H₅OH mixed solution using titanate nanotubes as precursor. The samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N₂ adsorption-desorption isotherms. The photocatalytic activity was evaluated by the photocatalytic oxidation decomposition of acetone in air and methyl orange in aqueous solution under UV illumination. The photocatalytic activity of HFTS was much higher than that of commercial Degussa P25 and tabular-shaped anatase TiO₂ obtained using pure water as the synthesis medium. The enhancement in photocatalytic activity was related to several factors, including the hierarchically porous structure, exposed {001} facets, and increased light harvesting ability. The HFTS was also of interest for use in solar cells, photocatalytic H₂ production, optoelectronic devices, sensors, and catalysis.

Key words: titanium dioxide, {001} facet, hierarchical flower-like titanium dioxide superstructure, photocatalytic activity, acetone, methyl orange