Fabrication of TiO2 hollow fibers with surface nanostructure

Polyvinyl alcohol–TiO2 (PVA–TiO2) core sheath nanofibers were fabricated by electrospinning an aqueous solution of PVA and introducing the thread-like droplets directly into a titanium tetraisopropoxide (TTIP)/hexane solution. Rod-like and sheet-like structures of lepidocrocite-type layered titanate formed on the surface of the TiO2 sheath of the nanofibers by alkaline treatment in 1 mol L−1 aqueous NaOH solution at 363 K. The nanofibers were converted to hollow TiO2 nanofibers with surface nanostructure and anatase crystallinity by acid treatment to remove sodium ions and heat treatment at 773 K. The surface nanostructures enhanced the crystallinity and external surface area of the nanofiber and contributed to the improvement of photocatalytic oxidation activity.