Synthesis of Self-Organized Polycrystalline F-doped TiO₂ Hollow Microspheres and Their Photocatalytic Activity under Visible Light

Abstract

A wet-chemistry method was used to dope F - ions into crystalline TiO 2 by hydrothermal treatment of TiF 4 in an HCl solution. Field-emission electron microscope and transmission electron microscope images showed that the products exhibited a flowerlike morphology with a hollow interior. X-ray photoelectron spectroscope data demonstrated the doping of F in the lattice of crystalline TiO 2 . The flowerlike F-doped TiO 2 hollow microspheres synthesized at 180 °C showed the highest photocatalytic activity for the degradation of methylene blue under visible light irradiation. Ostwald ripening is the main reason responsible for the formation of the hollow interior of the F-doped TiO 2 micropheres, and the HF species generated from the hydrothermal reaction is believed to accelerate the formation of the TiO 2 hollow spheres.