MOF-derived N-doped carbon nanocages trap CoP nanoparticles anchored on rGO to modulate dielectric polarization behavior for microwave absorption

In order to gain a deeper insight into the effect of dielectric polarization behavior caused by defects and heterogeneous interfaces on microwave absorption capability, the structure of in situ grown cobalt phosphide in MOF-derived N-doped amorphous carbon nanocages (CoP/NC) anchored on reduced graphene oxide (rGO) sheets was used to control the number of defects and heterogeneous interfaces. The different dielectric polarization behaviors are expressed by the amplitude and range of the polarization relaxation peaks. More defects and heterogeneous interfaces not only cause more intense polarization loss, but also modulate the electromagnetic parameters to improve the impedance matching performance. The CoP/NC@rGO achieves strong absorption of -67.5 dB and absorption bandwidth of 7 GHz with only 4 wt%. First principles calculation shows the formation of interfacial dipole at the CoP-NC heterogeneous interface. This work provides a strategy for regulating microwave absorption properties by defect and heterogeneous interface-controlled polarization behavior.