MOF decomposed for the preparation of Co3O4/N-doped carbon with excellent microwave absorption

A composite of Co3O4/N-doped carbon (Co3O4/N–C) has been successfully fabricated from a MOF precursor by a facile hydrothermal route (150 ​°C) and subsequent annealing process at 700 ​°C under high vacuum conditions. The composite was confirmed to be Co3O4 by powder X-ray diffraction (XRD) techniques, while the morphology and components were observed via SEM and EDS. The participation of carbon was proved and the presence of minor N was also convinced by XPS spectra. The Raman spectrum was analyzed to further study the graphitization degree of carbon. The excellent microwave absorption properties of Co3O4/N-doped carbon material has been obtained, with the maximum reflection loss as high as −42.6 ​dB ​at only 1.5 ​mm thick and the maximum absorption bandwidth (<−10 ​dB) of 4.08 ​GHz (from 11.03 ​GHz to 15.11 ​GHz) at 2.0 ​mm thick. The excellent microwave absorption of Co3O4/N-doped carbon material depends on not only the dielectric loss and impedance matching, but also the geometrical effects.