Hydrothermal synthesis of reduced graphene oxide-Co3O4 composites and the excellent microwave electromagnetic properties

Reduced graphene oxide-Co3O4 composites (RGO-Co3O4) were synthesized by a simple hydrothermal method and the electromagnetic and microwave absorbing properties of RGO-Co3O4 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.