Hollow porous CoNi/C composite nanomaterials derived from MOFs for efficient and lightweight electromagnetic wave absorber

The perfect control over the constituent and architecture of porous nanomaterials is still a significant challenge in developing high performance electromagnetic wave absorption materials. In this work, we have designed and prepared a novel lightweight electromagnetic wave absorption material with the combination of hollow structure and bimetallic constituents by the thermal decomposition of metal−organic framework (MOF) ZIF-67. We found that by introducing additional metal Nickle into the porous Co/C composites, the CoNi/C-800-PVDF nanocomposite could yield an excellent reflection loss of −61.02 dB at 13.68 GHz and simultaneously possess effective absorbing bandwidth of 5.2 GHz with lower filler loading as 10 wt%, which corresponding to a less absorber thickness of 2 mm. These results demonstrate that the synergistic effects between the bimetallic components and hollow structure of novel CoNi/C composite optimize impedance matching, and thus improve the absorption performance greatly. The properties of specific surface area, interface polarization, dipole polarization, ferromagnetic resonance, eddy current loss and multiple scattering are investigated to further explain the high performance of materials.