Self-assembly magnetized 3D hierarchical graphite carbon-based heterogeneous yolk-shell nanoboxes with enhanced microwave absorption

Rational manipulation of three-dimensional (3D) hierarchical structures can considerably enhance the performance of microwave absorption (MA) through the strong interface polarization caused by the abundant heterogeneous interfaces between low-dimensional components and the reflection loss resulting from voids and spaces within heterostructures. In this work, the yolk-shell structure with a 3D hierarchical graphite carbon (GC)/magnetic particle cubic core and an amorphous carbon shell is rationally constructed. With the help of the MOF-derived FeCo/GC template and the morphological stability role of residual SiO2 during the hydrothermal process, the reassembly of lamellar GC-based cores is obtained. The wise combination of GC and amorphous carbon provides the possibility of an appropriate graphitization degree. Moreover, nano-scale 3D magnetic coupling networks and various forms of component losses also play an active role in efficient attenuation. Therefore, the as-prepared absorber exhibits impressive MA performance, with an optimal reflection loss of as low as -60.03 dB and an effective absorption bandwidth of 7.04 GHz. This work provides a certain guideline for preparing 3D hierarchical graphite carbon-based heterogeneous microwave absorbers with improved performance, which can be achieved by the synergistic effect of multiple interfaces and multiple components.