TiO2 nanofibers embedding single crystalline TiO2 nanowires

Abstract

Epitaxially grown titanium dioxide (TiO2) nanofibers embedding single crystalline TiO2 nanowires (NWs) were successfully fabricated by electropinning poly(vinyl pyrrolidone)/ethanol solutions mixed with hydrothermally synthesized TiO2 NWs and titanium isopropoxide precursors and subsequently calcinating the electrospun nanofibers. Utilizing scanning electron microscopy (SEM) and transmission electron microscopy (TEM), the morphologies of TiO2 NWs and nanofibers were investigated. High resolution TEM (HR-TEM) and selected area electron diffraction (SAED) allowed us to indentify the fact that, during the calcination process under the optimized condition, titanium isopropoxide precursors were epitaxially crystallized on the surface of single crystalline TiO2 NWs. Based on the X-ray diffraction (XRD) experiments, it was also realized that the crystalline structure of hydrothermally synthesized TiO2 NWs and epitaxially crystallized TiO2 nanofibers is anatase and that TiO2 composite nanofibers embedding TiO2 NWs exhibited a higher crystallinity than the pristine TiO2 nanofibers. Additionally, ultraviolet visible (UV-Vis) spectra of nanofibers indicated that optical properties of TiO2 nanofibers can be tuned by introducing the single crystalline TiO2 NWs.