One-Pot Hydrothermal Synthesis of Co₃O₄/MWCNTs/Graphene Composites with Enhanced Microwave Absorption in Low Frequency Band

In this paper, the Co₃O₄/MWCNTs/Graphene ternary composite was synthesized by a facile one-pot hydrothermal method. The crystal structure, microstructure and elementary composition, electromagnetic parameters and microwave absorption property were systemically investigated by the XRD, SEM, TEM and VNA respectively. The results showed that the as-prepared ternary composite exhibits enhanced absorption property in the frequency range of 0.1–3.0 GHz, which is mainly attributed to the synergistic effects of the dielectric loss and magnetic loss. The enhanced dielectric loss mainly generates from the strong dipole and interfacial polarization of the adherent MWCNTs and embedded graphene fragments, and the enhanced magnetic loss derives from eddy current loss and nature resonance together. The maximum reflection loss of this composite can reach −42.56 dB at 0.39 GHz with a thickness of 5 mm, while the maximum effective absorption bandwidth covers from 0.77 GHz to 1.99 GHz with a relatively thinner thickness of 2 mm. This study provides a facile method to synthesize Co₃O₄/MWCNTs/Graphene composite with excellent properties that is a potential candidate for microwave absorption in low frequency band.