Enhanced low-frequency microwave attenuation in porous carbon modified with Fe/Ti: attenuation mechanisms based on interfacial microstructure and chemical state scales

Electromagnetic wave (EMW) pollution from the rapid expansion of electronic technologies necessitates lightweight, broadband, high-performance absorbers. However, most bamboo-derived carbons still suffer from a single dominant dielectric loss mechanism and limited attenuation in the low-frequency band, which severely restrict their practical application in EMW absorption. Herein, bamboo-derived magnetized porous carbon (MPCN&TiC) was synthesized with Fe ions as graphitization catalysts and further modified in strong magnetic field to incorporate two-dimensional Ti3C2Tx. Structural and compositional analyses revealed that Fe promoted graphitization and pore formation, while Ti3C2Tx introduced abundant defects, interfacial polarization centers, and Ti-Fe-C solid solutions. The identification of multiple chemical states of Fe and Ti demonstrated that the electronic heterogeneity at the atomic level serves as the driving force for enhanced dielectric polarization and efficient charge redistribution across the heterointerfaces. As a result, MPCN&TiC achieved a minimum reflection loss of − 54.0 dB at 4.6 GHz with a thickness of 5.0 mm, accompanied by an effective absorption bandwidth of 1.7 GHz in the low-frequency region. In contrast, MPCN showed strong absorption at higher frequencies (− 19.5 dB at 14.2 GHz, 1.3 mm thickness). The distinct absorption behaviors were attributed to the synergistic effects of defect engineering, heteroatomic coordination, and impedance matching optimization. This work demonstrates a rational strategy for tailoring the microstructure and electronic environment of biomass-derived carbons to achieve efficient and tunable EMW absorption, particularly in the low-frequency range.