Electrospun Fe2O3 nanotubes and Fe3O4 nanofibers by citric acid sol‐gel method

Citric acid‐based sol‐gel method has been used to synthesize metal oxides widely. Iron‐based one‐dimensional nanostructured materials, including Fe₂O₃ nanotubes and Fe₃O₄ nanofibers, have been successfully prepared by directly annealing electrospun citric acid‐based precursor fibers under different atmospheres in this study. Thermo‐gravimetric and differential thermal analyses were carried out from room temperature to 800°C under air and argon atmosphere, respectively. The results reveal the formation mechanisms for Fe₂O₃ nanotube and Fe₃O₄ nanofiber. Fe₂O₃ tubular structures with average inner diameter about 500 nm and wall thickness about 20 nm were obtained. Fe₃O₄ nanoparticles were self‐assembled along the one dimensional orientation to form Fe₃O₄ nanofibers with average diameter around 500 nm. The reflection losses as a function of frequency for the samples with 23 and 33 wt% Fe₃O₄ nanofibers in paraffin were examined. The frequency dependence of reflection losses under various matching thicknesses (2, 3, 4, 6 and 8 mm) was simulated. The as‐fabricated Fe₃O₄ nanofibers can be believed to be promising candidates as highly effective microwave absorbers.