Synthesis of Si-based KH560/RGO@Fe₃O₄ composite for improving electromagnetic properties in 2–18 GHz frequency range

Silicon coupling reagent is regarded as a common additive on surface treatment of polymer due to its high bonding strength and low cost. In this paper, a series of γ-(2, 3-epoxypropoxy) propyltrimethoxysilane (KH560)-based reduced graphene oxide (RGO)@Fe₃O₄ (KH560/RGO@Fe₃O₄) composites with different ratio of Fe₃O₄ nanoparticles (NPs) are synthesized by a facile hydrothermal method. It is confirmed that the silicon reagent KH560, as a hopeful candidate for increasing the RGO lattice defects, is favorable to improve the electromagnetic wave absorption. Meanwhile, the microwave attenuation mechanism of KH560/RGO@Fe₃O₄ composite suggests that the dielectric loss mainly causes by multiple Debye dipolar relaxation and its magnetic loss comes from the eddy-current effect of Fe₃O₄ NPs over the high frequency range. In consequence, the KH560/RGO@Fe₃O₄ composite endows the excellent absorption performance, the reflection loss (RL) value is optimized to − 25 dB at 14.1 GHz with a thickness of 3 mm and the maximum frequency bandwidth for RL < − 10 dB is 4.1 GHz with a thickness of 4 mm.