Synthesis by electrospinning and characterization of niobium pentoxide (Nb2O5) fibers

Abstract

Electrospinning is a method that uses high voltage and low electrical currents to produce fibers with reduced diameter, when a jet of a fluid material is accelerated and stretched in the presence of an external electric field. Niobium pentoxide has shown promising results for application to photocatalysis because it is easily recovered and recycled at the end of the process. In this paper, the composite fibers Nb/PVP (polyvinylpyrrolidone) were produced by the method of electrospinning. These fibers were heat treated at 600 e 700°C to obtain ceramic fibers of niobium pentoxide. Finally, the fibers were characterized by thermal analysis, X-Ray diffraction, scanning electron microscopy (SEM) and diffuse reflectance spectroscopy (DRS). The results showed that fibers were formed and presented hexagonal phase (TT-Nb2O5), and that the increase of the voltage caused a decrease in fiber diameter, with the smallest average diameter of 0,09 ?m obtained for fibers produced by applying a voltage of 16 kV and sintering at 700°C. The average crystallite size increased from 17,05 to 35.58 nm with increasing calcination temperature, resulting in decreased surface area of 43.5 to 31.3 m2/g. The band gap values measured ranged from 3.52 to 3.57 eV, indicating that the nanofibers are wide band gap semiconductors.

Key words: electrospinning, niobium pentoxide, nanofibers.