A novel hierarchical structure comprised of biomass-derived porous carbon and silicon carbide nanowires for highly efficient microwave absorption

Recently, porous carbon-based composites with nano- or micro-pores have been considered as attractive alternatives for microwave absorption. However, the dispersity and uniformity of nanomaterials in the porous carbon is not desirable, inducing poor interfacial compatibility and impedance mismatch. Herein, a novel biomass-derived hierarchically porous C/SiC composite (HPCC) with a two-level structure was successfully fabricated. The first level of microscale porous structure templated from dried apple, while the nanoscale bioinspired structure was constructed by in situ growth of SiC nanowires. The hierarchical structures were conducive to enhancing the microwave absorption performance of HPCC. The reflection loss of HPCC was −44.2 dB at a thickness of 1.5 mm, and the broad effective absorption bandwidth reached 4.2 GHz. The synergistic effects of the hierarchical structure on adjusting the impedance matching and the multiple loss mechanisms were investigated in detail. The results provide valuable guidance for fabricating hierarchical structures with high microwave absorption performance.