Nanostructured MnFe2O4 anchored on graphene oxide and reduced graphene oxide sheets for effective regulation of microwave absorption performance

Abstract

Herein, the composites of MnFe 2 O 4 -graphene oxide (MFO@GO) and MnFe 2 O 4 -reduced graphene oxide (MFO@rGO) were investigated for their structural and microwave absorption properties. The X-ray photoelectron spectroscopy confirmed the presence of C, O, Fe, and Mn elements, as well as the dominance of Fe 3+ over Fe 2+ and Mn 2+ over Mn 3+ oxidation states of Fe and Mn, respectively. The microwave absorption characteristics of composites were discussed in terms of filler loading, dielectric/magnetic loss mechanisms, effective absorption bandwidth (EAB), reflection loss (RL), skin depth, and impedance matching (Smith charts) criteria. The MFO@rGO composites exhibited the best microwave absorption properties (>90% absorption efficiency) over the entire frequency range examined (1–13.5 GHz) among the others. The MFO@rGO composite with 70 wt% filler loading achieved a minimum RL of −38.71 dB at 10.98 GHz and EAB (RL≤10 dB) of 3.40 GHz (9.48–12.88 GHz) for a thickness of 1.8 mm within the vicinity of impedance matching criteria. • A lightweight GO/rGO-MFO microwave absorber with broad EAB was fabricated • Incorporation of rGO in MFO improved impedance matching and widened the EAB. • Defect dipole polarization in rGO-MFO played a key role in microwave attenuation. • Minimum RL of −38.71 dB with EAB of 3.40 GHz was achieved for 1.8 mm thickness. • Results are superior to many reported composites based on GO and rGO.