LAUSR

Abstract We are reporting on well-designed single-layered and gradient concentration triple-layered microwave-absorbing composites based on functionalized reduced graphene oxide (FRGO). The RGO-[Co2L2Cl3]Cl, called FRGO, was fabricated through systematic experimental efforts by the covalent attachment of the 2,6-diamino-3-[(2-carboxylicacid) phenylazo]-pyridine (L)/Cobalt (Co) complex with graphene oxide (GO) functionalities. The formation of FRGO was proven by a series of characterization techniques, such as XPS, FTIR, XRD, Raman spectroscopy, FESEM, and TEM. The consideration of RGO-[Co2L2Cl3]Cl as a highly efficient microwave-absorbing material is a result of its magnetoelectric synergistic effect, impedance match, and multiple scattering. The maximum reflection loss (RL) of single-layered an RGO-[Co2L2Cl3]Cl/epoxy resin composite can reach −16.32 dB at 8.69 GHz, which corresponds to a composite with 30 wt % absorber loading and a thickness of 4.5 mm. For the triple-layered composite with increasing mass percentage (10–20–30 wt %) of RGO-[Co2L2Cl3]Cl in the direction of microwave propagation, the maximum reflection loss value of −34.9 dB can be achieved at 10.69 GHz, with a coating layer thickness of 4.5 mm. The result demonstrates that the RGO-[Co2L2Cl3]Cl/epoxy resin composites of both models can be ideal microwave-absorbing candidates for application in the X-band.