Porous\nCo–C Core–Shell Nanocomposites Derived from Co-MOF-74\nwith Enhanced Electromagnetic Wave Absorption Performance

Abstract

The\ncombination of carbon materials and ferrite materials has recently\nattracted increased interest in microwave absorption applications.\nHerein, a novel composite with cobalt cores encapsulated in a porous\ncarbon shell was synthesized via a facile sintering process with a\ncobaltic metal–organic framework (Co-MOF-74) as the precursor.\nBecause of the magnetic loss caused by the Co cores and dielectric\nloss caused by the carbon shell with a unique porous structure, together\nwith the interfacial polarization between two components, the ferromagnetic\ncomposite exhibited enhanced electromagnetic wave absorption performance\ncompared to traditional ferrite materials. With the thermal decomposition\ntemperature of 800 °C, the optimal reflection loss value achieved\n−62.12 dB at 11.85 GHz with thin thickness (2.4 mm), and the\nbandwidth ranged from 4.1 to 18 GHz with more than 90% of the microwave\nthat could be absorbed. The achieved performance illustrates that\nthe as-prepared porous Co–C core–shell composite shows\nconsiderable potential as an effective microwave absorber.