Anchoring Fe3O4 into nitrogen-doped porous carbon through pyrrolic nitrogen engineering for high-performance electromagnetic wave absorption

The escalating proliferation of electronic devices has intensified electromagnetic pollution, driving urgent demand for efficient electromagnetic wave absorbing materials. Carbon-based absorbers are promising due to their lightweight and tunable dielectric properties, yet often suffer from poor impedance matching and a lack of magnetic loss. Herein, we develop a Fe 3 O 4 /nitrogen-doped porous carbon composite (Fe 3 O 4 /NPC) through a facile adsorption-calcination approach. By regulating the carbonization temperature, the content and configuration of nitrogen dopants in NPC are effectively controlled, which in turn governs the adsorption of Fe 3+ and the subsequent formation of Fe 3 O 4 nanoparticles during thermal reduction. It is found that pyrrolic nitrogen not only enhances dipole polarization relaxation but also promotes uniform loading of Fe 3 O 4 nanoparticles. The optimized Fe 3 O 4 /NPC exhibits excellent impedance matching and attenuation capacity, achieving a remarkable reflection loss of −53 dB and an effective absorption bandwidth of 5.1 GHz at thin thickness of 1.82 mm. This performance surpasses the majority of previously reported magnetic carbon composites for EWA. Systematic electromagnetic analysis reveals that the superior performance originates from the synergistic effects of dielectric and magnetic losses, including interfacial polarization, defect-induced dipole relaxation, conductive loss, and magnetic loss. This work highlights the critical role of nitrogen configuration in mediating magnetic nanoparticle dispersion and presents a feasible strategy for designing lightweight and efficient EWA materials.