Fabrication of nanostructured hollow TiO2 nanofibers with enhanced photocatalytic activity by coaxial electrospinning

Two types of hollow crystalline titanium dioxide (TiO2) nanofibers were successfully fabricated through a facile coaxial electrospinning technique, with titanium sol and titanium precursor respectively as the materials for the shell. The two types of hollow TiO2 nanofibers possessed a similar tubular feature on the nanometer scale, but different morphology on surface nanostructures and size on shell thickness. Hollow nanofibers prepared by using titanium sol demonstrated that a small amount of water in core could prevent efficiently the diffusion of the core and shell solutions. For the titanium precursor without spinnability, it could be coated on the poly(vinyl pyrrolidone) core nanofibers as shell templates during the coaxial electrospinning process and properly developed into nanostructured TiO2 wall of the hollow nanofibers. Both of hollow TiO2 nanofibers exhibited higher photocatalytic activity for degradation methylene blue in comparison with the solid TiO2 nanofibers prepared by normal electrospinning due to their unique hollow structure.