Fabrication of Inorganic Oxide Nanofibers Using Gas Jet Fiber Spinning Process and Their Applications in Photocatalytic Oxidatio

A new, simple, and efficient Gas Jet Fiber (GJF) spinning process was used for fabrication of polymer precursor fibers from polymer precursor sol solutions with diameters ranging from a few hundreds of nanometers to a few micrometers, which on subsequent calcination in air resulted in the production of semiconducting metal oxides (SMO) nanofibers.;One of the primary objectives of this research work was to fabricate SMO nanofibers for use in photocatalytic oxidation of toxic volatile organic compounds (VOCs) that cause indoor air pollution and to degrade organic pollutants in water treatment applications. Another objective was to create specific arrangements of inorganic oxide or ceramic components in the same nanofibers so as to obtain morphologies that exhibit interesting physico-chemical properties useful in photocatalytic applications.;The basic strategy adopted in this work included a synergy of wet precursor sol-gel chemistry and GJF spinning followed by thermal treatment for the synthesis of ceramic nanofibers. First, we investigated and optimized the process for fabrication of titanium dioxide (TiO2), vanadium pentoxide (V 2O5), and tin-doped indium oxide (ITO) nanofibers. TiO 2 nanofibers exhibited a significantly higher (i.e., almost one order of magnitude) UV-light driven ethanol photocatalytic oxidation rate compared to a commercial grade P25 TiO2 nanoparticles. Second, the production of SMO nanofibers with core-shell (CS) and side-by-side (SBS) configurations was studied for a pair of inorganic oxides. TiO2, ITO, and V 2O5 were used for fabrication of bi-component CS and SBS nanofibers. Third, the fabrication strategy for hierarchical V2O 5-TiO2 nanostructure from a homogeneous sol solution of a mixture of SMO precursors and polymer in volatile solvents was developed. Nanofibers were successfully obtained with diameters below 200 nm exhibiting a hierarchical 'nanorods-on-nanofiber' morphological form as a result of calcination of the as-spun polymer precursor fibers at 500-600 °C. The V2O 5-TiO2 nanofiber heterostructure calcined at 500 °C showed upto two orders of magnitude higher ethanol photocatalytic oxidation rate under visible light than that of a reference V2O5 powder and a V2O5 nanofiber calcined at 500 °C. This observation can be attributed to the visible light absorbance characteristic of V 2O5 counterpart and their unique hierarchical heterostructures. In addition, the role of mesoporous surface area, carbon content, and crystallinity were found to be responsible for higher photocatalytic performance of the materials included in this work.