Sustainable hierarchical carbon architectures from bamboo for enhanced electromagnetic wave dissipation

Biomass-derived carbon materials are promising candidates for lightweight electromagnetic wave absorbers, yet their practical performance is often limited by insufficient impedance matching and single loss pathways. In this work, a hierarchically porous magnetic bamboo-based carbon composite was rationally designed through sodium hypochlorite oxidation, in-situ synthesis of magnetic particles, and subsequent in-situ pyrolysis. The oxidative pretreatment effectively removed lignin and exposed abundant hydroxyl groups, facilitating uniform metal ion infiltration and the construction of a highly anisotropic porous conductive carbon skeleton. During pyrolysis, iron species were transformed into well-dispersed Fe₃O₄-based magnetic nanoparticles, generating abundant heterogeneous interfaces within the carbon matrix. The resulting composite exhibits synergistic dielectric and magnetic loss behaviors, including conduction loss, interfacial polarization, dipole relaxation, and multiple magnetic resonance processes. Owing to the rationally engineered heterointerfacial configuration and the enhanced impedance compatibility, the optimized material exhibits exceptional electromagnetic wave attenuation behavior, delivering a minimum reflection loss as low as -64.86 dB at a thickness of 1.5 mm together with an effective absorption bandwidth of 4.06 GHz. Radar cross-section simulations further verify its remarkable capability for suppressing far-field microwave scattering. Overall, this work presents a viable route for developing heterointerface-enriched, biomass-derived magnetic absorbers and offers valuable insights into the value-added exploitation of bamboo-based carbon materials for advanced electromagnetic attenuation applications.