Biomass derived honeycomb porous carbon combined with metal oxide for broadband microwave absorption

Biomass-derived porous carbon materials are simple, low-cost, convenient, and sustainable materials with several advantageous features, such as multilevel porosity and structural repeatability. Herein, a new strategy involving the use of peanut shells and Fe 3 O 4 to prepare excellent absorbing materials is reported. During the carbonization process, the peanut shells transform into interconnected honeycomb-like porous carbon and Fe 3 O 4 nanoparticles are synthesized from FeCl 3 · 6H 2 O, FeCl 2 · 4H 2 O, and NH 3 · H 2 O through a hydrothermal method. The obtained microwave absorption materials (MAMs) P-C-800@Fe 3 O 4 (1:0.5) exhibits outstanding MA performance. The composite exhibits the minimum reflection loss ( RL , −59 dB) at a thickness of 3.9 mm, and the effective absorption bandwidth ( RL  < −10 dB) reaches 5.98 GHz at 2.3 mm. The synergistic enhancement between dielectric and magnetic losses enhances the MA capability of the honeycomb-like composite materials. Overall, this paper provides a prospective and convenient strategy for preparing biomass-derived honeycomb-like carbon for MA applications.