Facile synthesis of reduced graphene oxide-wrapped CNFs with controllable chemical reduction degree for enhanced microwave absorption performance

The rGO-wrapped nanocomposites can be regarded as promising candidates for the development of advanced microwave absorbing materials. In this work, hierarchical rGO-wrapped CNFs were prepared via a two-step strategy, including a classical modified Hummers method and a green reduction reaction. Accompany with the chemical treatments, graphene oxide appears on the outer walls of carbon nanofibers . By modulating the addition amount of ascorbic acid , the outer graphene oxide can be controllably reduced. Moreover, the CNFs/rGO with proper reduction degree exhibits desirable microwave absorption performance, whose minimum RL and effective bandwidth are −38.1 dB (3.85 GHz, d = 5.0 mm) and 4.1 GHz (5.08–9.18 GHz, d = 3.5 mm). The superior microwave attenuation performance is attributed to the synergistic effects between the CNFs and rGO . While the nanofibers provide the obtained sample with an extremely long conductive network, rGO introduces a moderate amount of lattice defects and functional groups, resulting in desirable conductivity loss and multiple polarizations. The existence of rGO also endows CNFs/rGO with suitable dielectric values so that the absorber achieves well impedance matching. Considering the excellent microwave absorption performance, this research provides a new facile route to fabricate rGO-wrapped carbonaceous materials with proper oxygen-containing groups for MAMs.