Lightweight and high-efficiency microwave absorption of reduced graphene oxide loaded with irregular magnetic quantum dots

Abstract

Due to the excessively high electrical conductivity and single dielectric properties of the graphene material, when used as a wave absorbing material, the imbalance of impedance matching causes strong reflection effects, resulting in poor wave absorbing performance. In this research, we partially reduced graphene oxide (GO) and loaded magnetic quantum dots (MQDs) through a one-step pyrolysis method, and a novel composite material of three MQDs (Fe, Fe3O4, Fe3C) embedded partially reduced graphene oxide (P-rGO) was prepared and the influence of pyrolysis temperature on its electromagnetic performance was systematically studied. The research found that ethylene glycol selectively reduced the CO functional group of the GO component and enhanced its dielectric properties; the loading of MQDs for a single carbon material increased the magnetic loss mechanism and improved the impedance matching and attenuation capabilities. In addition, the flaky structure of GO and the ultra-small nanostructure of MQDs suppress the eddy current effect and promote the occurrence of exchange resonance between magnetic particles. The prepared four sets of samples exhibit excellent absorbing properties in the 2–18 GHz frequency band. Among them, the samples prepared by pyrolysis at 800 °C can obtain 5.59 GHz broadband electromagnetic wave absorption at an ultra-thin thickness of 1.7 mm. The special quantum size effect and enhanced electromagnetic wave attenuation capabilities are the main reasons for the high-efficiency microwave absorption of MQDs/P-rGO composite materials.