Octahedron Fe ₃ O ₄ particles supported on 3D MWCNT/graphene foam: In-situ method and application as a comprehensive microwave absorption material

In this work, we used in-situ method to directly prepare a novel structure consisting of well-distributed octahedron Fe ₃ O ₄ particles, porous graphene foam (GF) and fibrous multiwalled carbon nanotube (MWCNT): started with an intense stir to anchor Fe ³⁺ on the surfaces of graphene oxide and oxided MWCNT, followed by solvothermal reaction to synthesize 3D lightweight Fe ₃ O ₄ /MWCNT/GF hybrids with high performance microwave absorption (MA). The maximum Reflection Loss (RL) value of −35.30 dB and 9.01 GHz bandwidth with RL below −10 dB detected with the thickness of 3.0 mm are achieved by Fe ₃ O ₄ /MWCNT/GF with an ultralow bulk density of 5.0 mg cm ⁻³ , of which the Specific Microwave Absorption Performance is much higher than most available MA materials reported. Impedance matching, high loss characteristic, interfacial polarization and polarization relaxation significantly improve MA properties, which serves as a guide for fabricating comprehensive MA materials enjoying numerous advantages of high RL value, broad bandwidth, low density and thin thickness.