Hydrothermal synthesis of reduced graphene oxide-Co₃O ₄ composites and the excellent microwave electromagnetic properties

Reduced graphene oxide-Co₃O₄ composites (RGO-Co ₃O₄) were synthesized by a simple hydrothermal method and the electromagnetic and microwave absorbing properties of RGO-Co ₃O₄ were investigated for the first time. The diameter of Co₃O₄ nanoparticles is in the range of 5-15 nm. Electromagnetic parameters showed that the electromagnetic attenuation mechanism of RGO-Co₃O₄ is mainly dependent on dielectric loss. The resulting microwave adsorption properties showed that the maximum reflection loss of RGO-Co₃O₄ is up to -43.7 dB at 13.8 GHz and the absorption bandwidth with the reflection loss below -10 dB is 4.6 GHz with a thickness of 3.3 mm. The excellent microwave absorption properties of RGO-Co₃O₄ can be used as an attractive candidate for the new type of microwave absorptive materials.