Tailored design of p-phenylenediamine functionalized graphene decorated with cobalt ferrite for microwave absorption

Structural design and componential optimization are two primary directions in the study of microwave absorbers. In this study, a novel cobalt ferrite (CoFe₂O₄) decorated with p-phenylenediamine (PPD) functionalized graphene (PG/CoFe₂O₄) binary hybrid with unique hierarchical porous structure was synthesized by a two-step route. The chemical composition, morphology and electromagnetic parameters of the as-prepared sample were investigated successively. The porous CoFe₂O₄ microspheres with an average diameter of about 160 nm were uniformly anchored on rGO nanosheets. Owing to the uniquely hierarchical porous structure, synergistic effects of dielectric loss (conductive loss, interface and dipole polarization) and magnetic loss (eddy current loss, natural and exchange resonance), the as-prepared sample exhibited excellent microwave absorption (MA) performance. The maximum reflection loss (RL_max) could attain up to -53.3 dB, and the effective absorption bandwidth (EAB) reached 6.6 GHz (11.4-18.0 GHz) at 2.40 mm, which completely covered the K _u band. These results showed that this functional material can be applied in the MA field.