Cobalt phthalocyanine-derived Co-C@C porous composites for tunable electromagnetic absorption

The metal-carbon nanocomposites are widely applied to electromagnetic wave (EMW) absorption due to their good impedance matching characteristics and multiple attenuation mechanisms. Here, the cobalt@carbon (Co-C@C) composites with the porous tubular structure were prepared by calcining the polydopamine (PDA) coated porphyrin derivative cobalt phthalocyanine (CoPc). The heating temperature has a significant effect on the morphology, porosity, magnetization intensity, and EMW absorption performance. These results show that Co-C@C composites after heat treatment temperature at 800 C have the best EMW absorption performance because of their large specific surface area, abundant mesopores and macropores, and high magnetization. Meanwhile, the Co-N bond could generate at the surface of cobalt nanoparticles, resulting in an interfacial effect and enhancing polarization loss. The minimum reflection loss (RLmin) is-47.36 dB at 12.76 GHz and the effective absorption bandwidth (EAB) is 5 GHz. In addition, Co-C@C composites can be used as tunable EMW absorbers with superior performance.

Automated summary

The cobalt@carbon nanocomposites with a porous tubular structure exhibit excellent electromagnetic wave absorption performance due to their large specific surface area and abundant porosity. The Co-N bond on the surface of cobalt nanoparticles enhances the absorption performance.