All chemical reagents used in the present work were
analytical grade and used as received without further purification. BiFeO3 nanofibers were fabricated by an electrospinning method described as follows. 2 g of Bi(NO3)3 5 H2O
and 1.5 g of Fe(NO3)3 H2O were dissolved in 5 mL of
2-methoxyethanol under mechanical stirring. Then 2.5 mL of
glacial acetic acid and 0.025 mL of ethanolamine were added
to adjust the viscosity and pH value of the solution under
constant stirring. Polyvinyl pyrrolidone (PVP) with molecular
weight 130,0000 was added to 11.25 mL of dimethyl forma-
mide (DMF)/acetone (2:1 v/v) mixed solvent. The above two
solutions were mixed and stirred continuously to form a
homogenous 0.08 g/ml PVP solution. The obtained precursor
solution was then loaded into a plastic syringe for the
electrospinning. The needle tip of the syringe was connected
to a high voltage that can generate a direct current (DC)
voltage of 13 kV. An aluminum foil was employed as the
collector attached to the cathode, and the distance between the
needle tip and the collector was 10 cm. The solution jet was
solidified by evaporation of solvent and a nonwoven fibrous
mat was formed on the collector. The as-collected composite
nanofibers were dried in an oven at 60 1C for 24 h, followed
by heating at 350 1C for 30 min in air and thermal annealing
at 550 1C for 2 h in argon atmosphere.