Sterculia lychnophora seed-derived porous carbon@CoFe2O4 composites with efficient microwave absorption performance

Recently, biomass-derived porous carbon materials demonstrate great potential to develop high-efficient microwave absorbers. Herein, magnetic porous composites consisting of CoFe2O4 nanoparticles and biomass-derived carbon from sterculia lychnophora seeds are prepared via hydrothermal and pyrolysis methods. The dielectric and magnetic properties of composites are modulated by tuning the content of CoFe2O4 nanoparticles to optimize impedance matching characteristics and improve attenuation capabilities. Benefitting from multicomponent compositions and porous structures, the optimized composite exhibits superior microwave absorption performance with the minimum reflection loss value of −67.04 dB at 2.0 mm and an effective absorption bandwidth of 5.52 GHz (11.92–17.44 GHz) at the filler loading of 20 wt%. Besides, the composite achieves strong microwave absorption in multiband (3.92–18 GHz) by adjusting matching thickness. The outstanding microwave absorption properties of magnetic porous composites are attributed to the synergistic effect of interfacial polarization, dipolar polarization, conductive loss, magnetic loss, multiple reflection and scattering of incident microwaves. This work could provide references for the advanced development of biomass-derived porous microwave absorbers.