High Dielectric Fe3O4 and Fe2O3 Nanoparticles Deposited on Graphite Nanosheets for Electromagnetic Wave Absorption

Fe3O4/graphite nanosheets (GNs) nanocomposites were obtained by the solvothermal method and calcined in an air environment to obtain Fe2O3/GNs nanocomposites. The phase and microstructure can clearly demonstrate the evolution process of Fe3O4/GNs to Fe2O3/GNs nanocomposites. The Fe3O4/GNs nanocomposites will be converted from Fe3O4 to Fe2O3 during calcination to form nanoparticles. When the calcination temperature is 250 °C, the glucose on the surface of the S-250 sample begins to carbonize, resulting in an excellent reflection loss value of −66.593 dB when the thickness is 2.8 mm and the effective absorption bandwidth is 3.28 GHz. The mutual contact between the nanoparticles and GNs makes the composites produce more interface/dipole polarization and better impedance matching. Calcination converts Fe3O4/GNs to Fe2O3/GNs, which is a high-performance design with a unique structure and has potential applications in the field of electromagnetic-wave absorption.