Facile synthesis of Fe3O4 nanoparticles/reduced graphene oxide sandwich composites for highly efficient microwave absorption

Component regulation and microstructure design are two effective strategies to adjust electromagnetic parameters and improve the microwave absorption performance of materials. In this study, a facile synthesis strategy consisting of ultrasonic dispersion, blast drying, and roasting is proposed to build a sandwich-like graphene-based absorbent, in which Fe3O4 nanoparticles with adjustable content are sandwiched uniformly between reduced graphene oxide nanosheets. The sandwich structure can form multiple interfaces, prevent the aggregation of nanoparticles, facilitate interface polarization, and endow the material with multiple electromagnetic loss mechanisms, which is very beneficial for impedance matching and microwave attenuation. Notably, the effective absorption bandwidth achieves 5.7 GHz, and the minimum reflection loss value is -49.9 dB. In addition, the synthesis process is simple and suitable for large-scale production and possible industrial applications. Thus, this facile route to fabricate sandwich-like graphene-based absorbents provides new ideas and approaches for designing new graphene-based nanocomposites.