Facile Preparation of F and N Codoped Pinecone-Like Titania Hollow Microparticles with Visible Light Photocatalytic Activity

F and N codoped anatase titania (FN-TiO2) hollow microparticles with a diameter of 5-8 mu m were facilely fabricated through a simple one-step solvothermal method without template followed by calcination. The fabricated hollow microparticles exhibit a novel pinecone-like superstructure, which is composed of many individual conical microvilli radiated from the center to the rim of microparticles. Preliminary photocatalytic tests under visible light irradiation indicate an enhanced activity of FN-TiO2 hollow microparticles with novel pinecone-like superstructures toward degradation of methyl blue with respect to commercial P25 TiO2 nanoparticles and the other fabricated FN-TiO2 products in the current work. The effect of the HF amount and the solvothermal temperature on the morphology of product was also investigated. A possible formation mechanism was proposed on the basis of a series of time-dependent synthesis experiments.