A facile method to prepare polyvinylidene fluoride composite nanofibers with high photocatalytic activity via nanolayer coextrusion

The agglomeration of powder photocatalysts for water remediation can reduce the catalytic efficiency, and the difficulty to be recycled will cause the secondary pollution. A facile method suitable for volume production of polyvinylidene fluoride (PVDF)-based nanofibers as well as mat with high photocatalytic activity is proposed via nanolayer coextrusion, which is a new top-down method. Hydrophilic TiO2 and acidified multi-walled carbon nanotubes (MWCNTs) are used for the preparation of highly active PVDF photocatalysts. The preparation process is eco-friendly, and no organic solvents are used. The morphology and structure of PVDF/(TiO2/MWCNTs) composite nanofibers are investigated on scanning electron microscope and transmission electron microscope. Xray diffraction patterns confirm that TiO2 is still anatase on nanofiber surface after melting processing. PVDF/ (TiO2/MWCNTs) composite nanofibers exhibit high photocatalytic efficiency for the degradation of methylene blue in water. In photoluminescence and ultraviolet spectra, the red shift phenomenon of the absorption peak of the nanofibers is observed. It is found that MWCNTs can improve the photocatalytic efficiency of TiO2 in PVDF composite nanofibers, in which MWCNTs can be aligned along the naofibers and play a role as the bridge among TiO2 particles and enhance the transfer of electrons. This facile and high efficient method can be widely used for the volume production of various kinds of similar functional nanofibers in the future.