Photocatalytic Crystalline and Amorphous TiO(2) Nanotubes Prepared by Electrospinning and Atomic Layer Deposition

In this work core/shell composite polymer/TiO(2) nanofibers and from those TiO(2) nanotubes were prepared. First, poly(vinyl alcohol) (PVA) and poly(vinylpyrrolidone) (PVP) fibers were synthetized by electrospinning. They were covered with a 100 nm thick amorphous TiO(2) layer by atomic layer deposition at 50 °C. Later the polymer core was removed by two different methods: dissolution and annealing. In the case of dissolution in water, the as-prepared TiO(2) nanotubes remained amorphous, while when annealing was used to remove the polymers, the TiO(2) crystallized in anatase form. Due to this, the properties of amorphous and crystalline TiO(2) nanotubes with exactly the same structure and morphology could be compared. The samples were investigated by SEM-EDX, ATR-IR, UV-Vis, XRD and TG/DTA-MS. Finally, the photocatalytic properties of the TiO(2) nanotubes were studied by decomposing methyl-orange dye under UV light. According to the results, crystalline anatase TiO(2) nanotubes reached the photocatalytic performance of P25, while amorphous TiO(2) nanotubes had observable photocatalytic activity.