ZnO/Fe3O4 Nanoparticles Encapsulated in N-Doped Porous Carbon for Extraordinary Microwave Absorption

To acquire a superior microwave absorber, ZnO/Fe 3 O 4 nanoparticles have been successfully embedded into an N-doped honeycomb-like porous carbon (NPC) framework via a two-step process. The structure, morphology, and electromagnetic wave absorption properties of ZnO/Fe 3 O 4 /NPC composites have been characterized. Benefitting from the unique hierarchical porous architecture, the balanced impedance between ZnO and Fe 3 O 4 , and the synergistic effects between ZnO/Fe 3 O 4 nanoparticles and the carbon matrix, ZnO/Fe 3 O 4 /NPC exhibited an outstanding electromagnetic wave absorption performance. The minimum reflection loss ( R L ) could reach − 51.1 dB at 12.9 GHz when the thickness is 3.7 mm, with a wide effective absorption bandwidth ( R L ≤ 10 dB) of 5.28 GHz at a thickness of 2.2 mm. It is apparent that ZnO/Fe 3 O 4 /NPC has great potential as a high-efficiency microwave absorber. Graphical Abstract