Bimetallic-doped Zeolitic imidazole framework-derived Cobalt-Nitrogen-Carbon supported on reduced graphene oxide enabling efficient microwave absorption

Background A bimetal (Fe/Ni) doped cobalt-nitrogen-carbon matrix (Fe/Ni-CoNC) with hierarchical architecture originating from zeolitic imidazolate framework (ZIF-67) is purposely designed. Methods The metals within the Co-N-C matrix are well distributed. Besides, Fe/Ni-CoNC was supported on reduced graphene oxide (RGO). We demonstrate that the three-element combination can synergistically contribute to different advantages for microwave absorption. Therefore, the combination of Fe and Ni synergized the absorber to obtain a good impedance match for the best microwave absorption. Significant Findings The synthesized Fe/Ni-CoNC/RGO with optimized element components exhibited an excellent wave absorption of -51.6 dB at 7.2 GHz obtained with a thin thickness of 2.5 mm. When combining Fe/Ni-CoNC/RGO with a thermoset resin, namely polydicyclopentadiene (PDCPD), the final product reached a maximum absorption of -24.5 dB with a thickness of 1.5 mm. This compounding confirmed that interfacial polarization, defect polarization, and natural resonance are synchronously enhanced for improved absorption performance.