The synthesis of wide bandwidth,thin thickness,and high performance microwave absorbing materials has become a hot topic of current research.Metal-organic frameworks with heterojunctions and porous structures are cons...The synthesis of wide bandwidth,thin thickness,and high performance microwave absorbing materials has become a hot topic of current research.Metal-organic frameworks with heterojunctions and porous structures are considered as suitable candidates to meet these characteristics.Herein,heterogeneous CoFe@N-doped porous carbon polyhedron composites were successfully synthesized via Fe^(2+)to replace Co in zeolite imidazole frame-67.The dielectric properties of composites were enhanced by the replacement of Fe^(2+),and the synergistic effect of dielectric loss and magnetic loss was realized.The petal-like lamellar structure increases the travel of electromagnetic(EM)waves,and the formation of porous structures improves impedance matching.Specifically,a reflection loss of−67.30 dB was obtained at a thickness of 2.88 mm,and an ultrabroad wide effective absorption bandwidth of 8.40 GHz was obtained,covering most of the X-band(8–12 GHz)and the whole Ku-band(12–18 GHz).The radar cross section(RCS)reduction value can reach 29.4 dB·m^(2),which means that the radar detector has a smaller probability of detecting targets.This work describes the unique advantages of metal ion replacement metal-organic frameworks derived materials in structural design,impedance matching,and performance adjustment,and provides a new reference for the field of electromagnetic wave absorption.展开更多
基金supported by the National Natural Science Foundation of China(No.52102036)the Sichuan Science and Technology Program(No.2021JDRC0099).
文摘The synthesis of wide bandwidth,thin thickness,and high performance microwave absorbing materials has become a hot topic of current research.Metal-organic frameworks with heterojunctions and porous structures are considered as suitable candidates to meet these characteristics.Herein,heterogeneous CoFe@N-doped porous carbon polyhedron composites were successfully synthesized via Fe^(2+)to replace Co in zeolite imidazole frame-67.The dielectric properties of composites were enhanced by the replacement of Fe^(2+),and the synergistic effect of dielectric loss and magnetic loss was realized.The petal-like lamellar structure increases the travel of electromagnetic(EM)waves,and the formation of porous structures improves impedance matching.Specifically,a reflection loss of−67.30 dB was obtained at a thickness of 2.88 mm,and an ultrabroad wide effective absorption bandwidth of 8.40 GHz was obtained,covering most of the X-band(8–12 GHz)and the whole Ku-band(12–18 GHz).The radar cross section(RCS)reduction value can reach 29.4 dB·m^(2),which means that the radar detector has a smaller probability of detecting targets.This work describes the unique advantages of metal ion replacement metal-organic frameworks derived materials in structural design,impedance matching,and performance adjustment,and provides a new reference for the field of electromagnetic wave absorption.
