Fe-based material@N-doped carbon composites as environment-friendly microwave absorbers

Environment-friendly Fe-based material@N-doped carbon nanoparticles imbedded in polylactic acid (PLA) matrix are prepared and applied in microwave absorption field. In the synthesis process, polydopamine (PDA) in the precursor could rationally regulate the phases of the iron-based particles and carbon contents. It turns out that optimizing the chemical composition plays a vital role in modulating microwave absorption performance. For instance, the maximum reflection loss (R_Lmax) for Fe@N-doped carbon particles (S-120) reaches −61.6 dB (12.56 GHz, 2.1 mm), and the effective bandwidth is 4.48 GHz (from 13.52 GHz to 18 GHz) with a thickness of only 1.7 mm. The excellent microwave absorption performance could be attributed to perfect impedance matching brought by the synergies of multiple components. Moreover, the microwave absorbers display not only high microwave absorption performance but also environment-friendly characteristics that can avoid leaving stubborn waste after failure. The preparation process of the composite is pollution-free and the PLA in the composite can almost be naturally degraded within one month under simulated marine environment. This work may provide a new perspective on preparing high-efficient functional materials which are also harmless to the environment.