Used dye adsorbent derived N-doped magnetic carbon foam with enhanced electromagnetic wave absorption performance

The increasing excess electromagnetic wave (EMW) radiations induce a serious pollution problem. The social requests urgently for EMW absorbing materials. Herein, as-prepared magnetic carbon foam (MCF) adsorbed RhB from the dye pollutant solutions. The used adsorbent was heat-treated at high temperature. Then, magnetic particle-decorated N-doped carbon foams (N-MCFs) were fabricated. N-doping content is determined by mass ratio of adsorbed RhB vs MCF. Excellent EMW absorption performance is achieved by optimizing impedance matching of N-MCFs. N-MCF-2 with a loading rate of 15% exhibits a lowest RLmin value of -60.46 dB with a T-m value as thin as only 1.70 mm. The corresponding effective bandwidth is 14.29 GHz and 13.79 GHz for -10 dB and -20 dB, covering the whole C band, X band and Ku band. For the absorbers with higher conductivities, the corresponding EMW absorption capacity can be further improved by reducing the loading rate. The distorted skeletons caused by N-doping induce the graphite lattice distortion and local density change of the carbon atomic state, significantly contributing to the magnetic moment. The enhanced dielectric loss by both defect polarization and dipole polarization effects, as well as the activated complex permeability by alpha-Fe/Fe3C/Fe2O3 composites decoration, are beneficial to EMW absorption. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The increasing excess electromagnetic wave (EMW) radiations induce a serious pollution problem, leading to an urgent need for EMW absorbing materials. This study successfully fabricated magnetic particle-decorated N-doped carbon foams (N-MCFs) with excellent EMW absorption performance. The N-doping content and loading rate were found to have significant effects on the absorption capacity of the materials, which cover the whole C band, X band, and Ku band.