Electromagnetic wave absorption properties of mesoporous Fe3O4/C nanocomposites

In this work, the mesoporous Fe3O4/C nanocomposites with a yolk-shell structure (Fe3O4@void@C) were prepared by a silica-assisted strategy, and their microstructure, magnetic properties, and microwave absorption were studied in detail. The BET surface area and the total pore volume of Fe3O4@void@C are 171.5 m2 g−1 and 0.19 cm3 g−1, respectively. The composites show a saturation magnetization of 35.4 emu/g and reduced hysteresis loss at room temperature. The Fe3O4@void@C nanocomposites exhibit the obvious complementarities between complex permittivity and permeability. A minimum reflection loss value of −18.1 dB was obtained for the absorber thickness reaching 2.0 mm, and even the Fe3O4@void@C nanocomposites possess a lower reflection loss of-10 dB under 2 GHz bandwidth. We believe that the investigations on the Fe3O4@void@C nanocomposite open up a route to develop a new type of composite, which is considered as a promising candidate for microwave absorber.