Investigations on structure-dependent microwave absorption performance of nano-Fe3O4 coated carbon-based absorbers

It is reported the magnetic coating structure has a significant influence on their microwave absorption performance (MAP) for nano-Fe3O4-coated CNT. However, it is still uncertain which type of coating structure is favorable for Fe3O4-coated reduced graphene oxides (rGO) to enhance the MAP. In this work, nano-Fe3O4 compact-coated rGO (FCG) and Fe3O4 loose-coated rGO (FLG) are prepared firstly and their MAP have been investigated. A strong coating structure dependent effect is found and the FCG is proved to own much better MAP than FLG. Afterwards, the nano-Fe3O4 compact-coated CNT and rGO mixture (FCCG) are fabricated. It is shown that the MAP could reach as low as −42.9 dB, and the high coverage density of Fe3O4 nanoparticles plays important role on achieving this excellent property. Furthermore, in order to investigate the synergistic effects between CNT and rGO, FCCG with different mass ratios of CNT to rGO have been synthesized and optimized to maximize the effective complementarities between the dielectric loss and the magnetic loss to obtain high MAP. Results show the FCCG with 50 wt% rGO content achieves the best MAP, which can be attributed to the promoted consequent dielectric relaxation process and the magnetic loss induced by the increased multiple interface.