Construction of Fe3O4/PANI composites with hollow 0D/1D structures for efficient microwave absorption

In this study, a novel microwave absorber ferric oxide/polyaniline (Fe3O4/PANI) composite was successfully fabricated with 0-dimensional (0D) hollow Fe3O4 nanospheres and 1-dimensional (1D) hollow polyaniline (PANI) nanotubes using hydrothermal treatment and chemical oxidative polymerization. The results demonstrate that the prepared Fe3O4/PANI composites exhibit remarkable microwave absorption (MA) properties. It possesses a minimum reflection loss (RLmin) of −55.03 dB and an effective absorption bandwidth (EAB) of 4.88 GHz with a thickness of 1.84 mm. When the thickness is increased to 1.88 mm, the composite achieves a maximum EAB (EABmax) of 5.16 GHz (12.84–18 GHz) and an RL of −40.47 dB. The hollow structures of Fe3O4 and PANI reduce the weight of the absorber and also enhance the synergistic loss effects, including interfacial polarization loss and multiple reflection and scattering loss, resulting in improved MA properties. The combination of hollow 0D/1D structures provides a novel approach in designing lightweight and efficient composite MA materials.