Fabrication of hollow titania fibers by electro-spinning for photocatalytic degradation of organic dyes

Nanostructured titania (TiO2) fibers such as nonporous, macroporous, hollow, and hollow macroporous fibers were successfully prepared by electrospinning using titanium diisopropoxide bis (acetylacetonate) (TDIP) as starting material. Hollow TiO2 fibers were fabricated using two syringe pumps and dual concentric nozzle to prepare hollow microstructure inside the fibrous materials. Oil was supplied to core of nozzle and polymeric mixture containing the titania precursor was injected into outer layer of nozzle. Then, oil from electro-spun fibers was removed by washing with organic solvent to obtain hollow microstructure. Macroporous hollow titania fibers could be also fabricated from spinning solution composed of the titania precursor and PS nanospheres as sacrificial templates. Thickness of fiber walls of macroporous hollow titania fibers became thinner from 425.5 to 353.5 nm, when flow rate of titania precursor solution was adjusted from 15 to 10 μL/min. SEM, XRD, and FT-IR analysis were employed to characterize morphologies, crystallinity, and compositions of the fibers, respectively. Photocatalytic removal of methylene blue under UV light illumination was performed using four different kinds of the titania fibers to compare their photocatalytic activity. Rate constant of the degradation reaction could be estimated from experimental data during photocatalytic degradation, assuming first-order kinetics. The rate constant of hollow titania fiber (0.0772 min−1) was estimated as the highest value among various kinds of the nanostructured fibers, showing the best photocatalytic ability for decomposition of organic dyes.