Enhanced electromagnetic wave attenuation performance of hierarchical Fe3O4/N-doped carbon nanosheets by heterointerface engineering

The dielectric-magnetic composites with a unique structure are regarded as promising materials for addressing the issue of electromagnetic wave pollution. Herein, a series of hierarchical Fe3O4/N-doped carbon nanosheets (Fe3O4/HNCS) composites with adjustable electromagnetic wave attenuation (EMWA) properties were successfully fabricated by adjusting the proportion of iron source and carbon using a simple combination of molten salt and solvothermal methods. Among all the composites, the Fe3O4/HNCS-0.25 exhibits the strongest reflection loss (RL) value of - 52.08 dB with an ultra-thin thickness of 1.4 mm, corresponding to an effective absorption bandwidth (EAB) of 4.16 GHz. Furthermore, the Fe3O4/HNCS-0.20 achieves a maximum EAB value of 4.4 GHz, obtained at a thickness of 1.4 mm. The superior EMWA performances originate from excellent impedance matching, synergy between dielectric and magnetic loss, and unique hierarchical structure. This study presents a straightforward and environmentally friendly method for fabricating high -performance dielectric-magnetic EMWA materials with an ultra-thin matching thickness.