In-situ growth of metal organic framework on hollow graphene foam for high-efficiency microwave absorption

• A novel MA material was fabricated by in-situ growth of MOF onto hollow GrFs. • Co/C@GrFs achieve RLmin of −50.2 dB at 1.3 mm thickness and 7.1 wt% filler loading. • Co/C@GrFs exhibit an impressive microwave absorption efficiency of −38.6 dB/mm. • It is due to hierarchical pore structures and synergetic MOF-GrF interactions. The demand for lightweight, thin, and broadband microwave absorption materials has been growing rapidly with advancements in microelectronics and aerospace technology. Conventional microwave-absorbing materials often suffer from poor dispersion and limited electromagnetic attenuation capacity. Herein, we report a novel microwave absorption material that integrates ZIF-67-derived metal organic frameworks (MOFs) with hollow graphene foams (GrFs) synthesized via chemical vapor deposition. The hollow GrFs act as resonant cavities in enhancing multiple reflections and conductive loss, while the MOFs optimize impedance matching for highly efficient microwave absorption. The MOF@GrF-filled paraffin composites achieve a minimum reflection loss (RL min ) of −50.2 dB at a thickness of 1.3 mm and 7.1 wt.% filler loading, with an impressive microwave absorption efficiency of −38.6 dB/mm. This superior performance is attributed to the synergistic interactions between GrFs and MOFs, integrating conductive loss, cavity confinement, dipole polarization, interfacial polarization, magnetic loss, and improved impedance matching. This study paves a way for fabricating high-efficiency microwave absorption materials for application in fields of aerospace, medical equipment, and electronic industry.