摘要
Developing lightweight and broadband microwave absorbers for dealing with serious electromagnetic radiation pollution is a great challenge.Here,a novel Fe-Co/N-doped carbon/reduced graphene oxide(Fe-Co/NC/rGO)composite with hierarchically porous structure was designed and synthetized by in situ growth of Fe-doped Cobased metal organic frameworks(Co-MOF)on the sheets of porous cocoon-like rGO followed by calcination.The Fe-Co/NC composites are homogeneously distributed on the sheets of porous rGO.The Fe-Co/NC/rGO composite with multiple components(Fe/Co/NC/rGO)causes magnetic loss,dielectric loss,resistance loss,interfacial polarization,and good impedance matching.The hierarchically porous structure of the Fe-Co/NC/rGO enhances the multiple reflections and scattering of microwaves.Compared with the Co/NC and Fe-Co/NC,the hierarchically porous Fe-Co/NC/rGO composite exhibits much better microwave absorption performances due to the rational composition and porous structural design.Its minimum reflection loss(RLmin)reaches?43.26 dB at 11.28 GHz with a thickness of 2.5 mm,and the effective absorption frequency(RL≤?10 dB)is up to 9.12 GHz(8.88-18 GHz)with the same thickness of 2.5 mm.Moreover,the widest effective bandwidth of 9.29 GHz occurs at a thickness of 2.63 mm.This work provides a lightweight and broadband microwave absorbing material while offering a new idea to design excellent microwave absorbers with multicomponent and hierarchically porous structures.
Developing lightweight and broadband microwave absorbers for dealing with serious electromagnetic radiation pollution is a great challenge. Here, a novel Fe–Co/N-doped carbon/reduced graphene oxide(Fe–Co/NC/rGO) composite with hierarchically porous structure was designed and synthetized by in situ growth of Fe-doped Cobased metal organic frameworks(Co-MOF) on the sheets of porous cocoon-like rGO followed by calcination. The Fe–Co/NC composites are homogeneously distributed on the sheets of porous rGO. The Fe–Co/NC/rGO composite with multiple components(Fe/Co/NC/rGO) causes magnetic loss, dielectric loss, resistance loss, interfacial polarization, and good impedance matching. The hierarchically porous structure of the Fe–Co/NC/rGO enhances the multiple reflections and scattering of microwaves. Compared with the Co/NC and Fe–Co/NC, the hierarchically porous Fe–Co/NC/rGO composite exhibits much better microwave absorption performances due to the rational composition and porous structural design. Its minimum reflection loss( RLmin) reaches-43.26 dB at 11.28 GHz with a thickness of 2.5 mm, and the e ective absorption frequency(RL ≤-10 dB) is up to 9.12 GHz(8.88–18 GHz) with the same thickness of 2.5 mm. Moreover, the widest e ective bandwidth of 9.29 GHz occurs at a thickness of 2.63 mm. This work provides a lightweight and broadband microwave absorbing material while o ering a new idea to design excellent microwave absorbers with multicomponent and hierarchically porous structures.
基金
the National Natural Science Foundation of China(No.21376029)and the Analysis&Testing Center,Beijing Institute of Technology for sponsoring this research
supported by Beijing Key Laboratory for Chemical Power Source and Green Catalysis,Beijing Institute of Technology.
