Fabrication of carbon-core/TiO_2-sheath nanofibers by carbonization of poly(vinyl alcohol)/TiO_2 composite nanofibers prepared via electrospinning and an interfacial sol-gel reaction

摘要

Carbon-core/TiO_2-sheath nanofibers have been fabricated from poly(vinyl alcohol) (PVA)/TiO_2 composite nanofibers that were prepared by electrospinning an aqueous solution of PVA and introducing the thread-like droplets directly into a titanium tetraisopropoxide (TTIP)/heptane solution. The PVA/TiO_2 composite nanofibers were transformed into carbon/TiO_2 nanofibers by iodine vapor treatment at 353 K, which induced dehydration of PVA, followed by carbonization in N_2 at 873 K. The carbon/TiO_2 nanofibers had diameters of a few hundred nanometers and sheathes of tens of nanometers. The nanofibers were composed of carbon cores with a low degree of graphitization and TiO_2 sheaths with an anatase crystal structure. The electrical conductivity of the carbon/TiO_2 composite nanofibers was enhanced by 4 orders of magnitude compared with TiO_2 hollow nanofibers.