p ZnO nanofibers prepared by plasma assisted calcination: Characterization and photocatalytic properties

The ZnO nanofibers (ZnO-NF) have been fabricated by the novel approach of plasma assisted calcination using the low-temperature atmospheric pressure plasma generated by diffuse coplanar surface barrier discharge (DCSBD). The electrospun polyvinyl pyrrolidone/zinc acetate fibers were exposed to DCSBD plasma before the thermal processing at different temperatures (400 degrees C,500 degrees C and 600 degrees C) and characterized in term of chemical composition and morphological structure by ATR-FTIR, XPS, SEM, XRD, and BET analysis. The photocatalytic activity of prepared ZnO-NF has been investigated under UV-radiation using methylene blue and the kinetics of photodegradation and reusability were studied. The results showed that initial removal of organic matrix at lowtemperature by application of plasma leads to better formation of Zn-O even at lower calcination temperature. The plasma pre-treated (PT) fibers exhibit lower diameter of final products and helps to preserve a well-defined fibrous structure during thermal processing. The ZnO-NF prepared by a combination of plasma treatment and thermal processing showed significantly higher photodegradation activity and the difference was higher with decreasing calcination temperature. The highest rate constants were reached for fibers calcined at 600 degrees C with and without plasma treatment - kPT = 0.0149 min-1, kNT = 0.0107 min-1, respectively. The slight improvement of re-usability in cyclic photodegradation was observed on samples calcined at 600 degrees C.