C60/Co Nanoparticle/Carbon Nanoflake Composites for Dual-Loss Microwave Absorption

An ideal microwave absorption material involves multilevel precise regulation and construction at multiple scales, which remains a great challenge. For the first time, we develop a host–guest self-assembling strategy via the entrapment of fullerene C60 molecule guest in a zeolitic imidazolate framework-67 (ZIF-67) host to design the hierarchical structure for a high-performance microwave absorber covering the molecular scale, nanoscale, and microscale synergistic effects. Typically, the two-dimensional orientation growth of microscale ZIF-67 precursors in solution is achieved by introducing C60 molecules. After the accurate pyrolysis process, Co nanoparticles derived from C60@ZIF-67 are embedded into ultrathin carbon flake (CF) substrates, favoring uniformity, size diminishment, and surface stability. These as-synthesized uniformly dispersed C60/Co/CF composites possess advantages of dual dielectric and magnetic loss functions, exhibiting the great microwave absorption properties with a minimum reflection loss of −58.03 dB and the effective absorption bandwidth of 5.94 GHz. This proposed host–guest self-assembling strategy has great potential for the synthesis of other metal–organic framework materials in the field of microwave absorption.