Ultralight, hierarchical metal–organic framework derivative/graphene hybrid aerogel for electromagnetic wave absorption

On the basis of high-efficiency electrostatic assembly, a type of ultralight, hydrophobic, hierarchically porous aerogels composed of metal–organic framework (MOF)-derived magnetic γ-Fe 2 O 3 @C/graphene are prepared via facile, scalable freeze-drying followed by annealing approach. The interaction between MOF and graphene oxide leads to the uniform dispersion of MOF-derived magnetic nanoparticles in the graphene-based cell walls, endowing the aerogels with high conductive and magnetic losses as well as polarization loss capacity derived from abundant heterogeneous interfaces. Both the core–shell microstructure of MOF derivative and the hierarchical pores of aerogels are instrumental in the multiple scattering of electromagnetic waves (EMWs), further promoting the EMW loss capability. Combined with the optimized impedance matching arising from the synergy between dielectric and magnetic components, an excellent EMW absorption performance of aerogel is achieved. At a filling ratio of merely 5 wt%, a minimum reflection loss of − 60.5 dB and a broad effective absorption bandwidth of 7.76 GHz covering the entire Ku-band are accomplished, significantly outperforming previously reported MOF- or graphene aerogel-based EMW absorbers. This work thus offers an efficient design strategy to prepare ultralight MOF-based aerogels for high-efficiency EMW absorbing materials in applications of electromagnetic compatibility and aerospace. Graphical Abstract