Direct fabrication of La0.7Sr0.3FeO3 nanofibers with tunable hollow structures by electrospinning and their gas sensing properties

La0.7Sr0.3FeO3 nanofibers with tunable hollow structures are prepared by a facile single capillary electrospinning and annealing process. The hollow nanofibers are characterized by thermogravimetry and differential thermal analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and nitrogen physisorption isotherms. The tunable hollow structures are controlled by adjusting the weight ratio of (La(NO3)3·6H2O + Sr(NO3)2 + Fe(NO3)3·9H2O)/PVP. With the increasing of nitrate/PVP ratio, the diameter and the shell thickness of hollow nanofibers increase. Formaldehyde gas sensing properties are carried out in the concentration range of 0.1–100 ppm at the operating temperature of 240 °C. The gas sensing mechanism is also discussed.