Facile synthesis of graphene oxide-wrapped CNFs as high-performance microwave absorber

Abstract Graphene oxide/carbon nanofibers hierarchical structures have been successfully synthesized through a modified Hummers method. Owing to the harsh chemical exfoliation and oxidation, graphene oxide (GO) appears on the outer walls of carbon nanofibers (CNFs) with the preservation of the 3D fibrous network. By adjusting the oxidation time, the obtained sample exhibited excellent electromagnetic (EM) attenuation performance with a maximum reflection loss of −49.82 dB at a thickness of 1.5 mm. Meanwhile, an effective bandwidth of 2.48 GHz was also investigated. The superior EM absorbing performance of GO/CNFs is ascribed to the hierarchical structure. While the inner carbon skeleton endows the material with desirable conductive network, GO exhibits a larger surface area with abundant functional groups and defects that give rise to multiple polarizations and relaxation processes. Moreover, the resistance-capacitance coupled circuits formed in the GO/CNFs network are beneficial for dissipating the incident waves. Prospectively, the synthetic strategy applied in this research can be extended to assemble GO on carbonaceous materials to fabricate novel microwave absorbers.