Electrospinning synthesis and characterization of zirconia nanofibers annealed at different temperatures

The main goal of this study was to produce, in a two-step process, ceramic nanofibers, which were obtained by electrospinning of composite fibrous mats and high-temperature thermal treatment at temperatures of 500 and 600 °C. The next step was to determine the effect of the nanofibers calcination temperature on the morphology and surface, structural and optical properties and photocatalytic activity of zirconia nanostructures. For this purpose, ZrO₂ 500 and ZrO₂ 600 were analyzed using scanning electron microscopy with an energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy and nitrogen adsorption isotherms specific surface tests. The structure of zirconium oxide nanofibers was investigated using X-ray diffraction, which confirmed highly crystalline nature of the materials and the presence of two crystalline phases - monoclinic and tetragonal. Analysis of optical properties, carried out on the basis of graphs of absorbance as a function of wavelength, revealed width of the optical band gap equal to 4.9 and 5.6 eV for nanostructures calcined at 500 and 600 °C, respectively. The nanofibers with a lower energy gap and a higher specific surface area degraded 38.47 % of methylene blue in an aqueous solution under ultraviolet radiation within 210 min.