The solution of polyvinyl acetate (14 wt%) was prepared using DMF (2, 2-dimethyl formamide) as
solvent. 2 g of commercial Pr(NO3)3.6H2O powder (purity 99.5%, Sigma–Aldrich chemicals) was dissolved
in 2-propanol and stirred well. A transparent greenish color was obtained after stirring for
30 min. The electrospining solution was prepared by mixing the PVAc (14 wt%) solution with Praseodymium
nitrate solution in ratio of 3:1 and put the reaction mixture under stirring for 12 h. The obtained
solution was put in a 10 ml syringe with a stainless steel needle. A copper pin connected to a
high voltage generator was inserted in the solution as a positive terminal whereas a ground iron drum
covered by polyethylene sheet served as counter electrode. The solution was kept in the capillary by
adjusting the inclination angle. A voltage of 15 kV was applied to this solution. The distance between
the syringe needle tip and collector was fixed at 15 cm. The as-synthesized mat of composite fiber was
initially dried at 80 C for 24 h under vacuum, and then calcined at 600 C for 2 h in air atmosphere
with a heating rate of 2 C/min.