Facile preparation, high microwave absorption and microwave absorbing mechanism of RGO-Fe₃O₄ composites

Reduced graphene oxide (RGO)-Fe₃O₄ composites with obviously enhanced microwave absorption properties were successfully fabricated by a rational one-pot simplified co-precipitation route, which avoided the usage of an inert gas and any additional chemical agents (such as surfactants and stabilizers). Given these advantages, the strategy described in this study can be developed as a simple and large-scale route to yield RGO-Fe₃O ₄ composites. The morphology, structure, thermal stability, magnetic and microwave electromagnetic properties of the as-prepared composites were characterized by XRD, XPS, TEM, FT-IR, Raman, TG and VSM. These composites exhibit excellent microwave absorption properties, which are attributed to effective complementarities between the dielectric loss and the magnetic loss. The microwave absorption mechanism of the RGO-Fe₃O₄ composites was studied in detail. For the RGO-Fe₃O₄-3 composite, the maximum R_L reaches -44.6 dB at 6.6 GHz with a thickness of 3.9 mm, and the bandwidth of R_L less than -10 dB can reach up to 4.3 GHz (from 12.2 to 16.5 GHz) with a thickness of 2.0 mm. Moreover, the microwave absorption properties can be tuned easily by varying the (RGO)/(Fe₃O₄) ratio and layer thickness of the samples. It is believed that such composites will find wide applications in the microwave absorbing area.