Controllable synthesis of mesoporous F-TiO₂ spheres for effective photocatalysis

An effective bottom-up synthesis strategy has been developed to prepare monodisperse mesoporous F-TiO₂ spheres consisting of anatase nanocrystallites. The spherical morphology is derived from nonporous hydrous TiO₂ spheres obtained from the direct precipitation of titanium alkoxides under the direction of dodecylamine (DDA) in water-containing ethanol-acetonitrile mixed solution, and a mesoporous structure is generated and stabilized by a subsequent solvothermal reaction in NH₄F-contaning ethanol solution. After calcination, mesoporous F-TiO₂ spheres with a diameter around 250 nm are fully crystallized with a large surface area of 132 m² g^-1, and a pore size of 8.5 nm. Ascribed to their accessible mesoporous structure, well-packed anatase nanocrystallites, excellent light harvesting property, and surface fluorination, the resulting mesoporous F-TiO₂ spheres show enhanced light harvesting in the UV-Vis range as well as superior photocatalytic activity in dye degradation.