Facile one-pot synthesis of surface-fluorinated TiO2 hollow spheres with enhanced photocatalytic activity

Surface-fluorinated TiO2 hollow spheres were synthesized in a one-pot synthesis from dissolved ammonium hexafluorotitanate and boric acid without any surfactants or templates. The effect of reaction time on the morphology and structure of the synthesized sub-micro spheres was investigated and characterized by field emission scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Also, the detailed growth formation mechanism of hollow spheres via self-transformation and outward Ostwald ripening processes is discussed. The photocatalytic activity of the prepared samples was analyzed under ultraviolet light, based on the photocatalytic decomposition of rhodamine B aqueous solution at room temperature. A significant improvement in photocatalytic efficiency of the synthesized TiO2 hollow powder was observed, which was due to the combined effects of its high surface area, high crystallinity, and surface fluorination.