MOFs-derived Co/C nanoparticle embedded in N, S co-doped graphene for superior electromagnetic wave absorption capacity

Abstract

Due to their physicochemical properties, the three-dimensional Metal-organic frameworks (MOFs) derived composites show great potential as electromagnetic wave (EMW) absorbers. However, poor impedance matching limits their actual EMW absorption performance. Composite materials that combine magnetic and dielectric losses offer a potential solution to enhance impedance match and significantly improve microwave absorption. In this work, a novel N,S-GS/Co/C composite was fabricated via a solvothermal method and a subsequent pyrolysis process to introducing nitrogen and sulfur co-doped graphene (N,S-GS) into Co-MOF. By co-doping nitrogen and sulfur, abundant defects and disordered sites were introduced on graphene, which stimulate interfacial polarization and dipole polarization. The minimum reflection loss (RL) of the sample obtained by pyrolysis at 600 °C is −68.8 dB at 9.7 GHz. Simultaneously, the thickness is 2.51 mm, and the effective absorption bandwidth (EAB) can reach 3.04 GHz. Its excellent EMW absorption performance is mainly attributed to interfacial polarization, multiple reflections, dipole polarization, magnetic resonance and eddy current loss. Accordingly, the N,S-GS/Co/C composite is convinced to be a competent candidate among EMW absorbers with high absorption intensity.