Ternary Mo₂C/Co/C composites with enhanced electromagnetic waves absorption

Transition metal carbides with good chemical stability and moderate dielectric constants are becoming popular electromagnetic (EM) absorption materials. In this work, Mo₂C/Co/C composites, a ternary loss system (conductivity loss, polarization loss, and magnetic loss) for EM absorption, have been successfully fabricated by rationally regulating the growth of ZIF-67 on the surface of MoO₃ nanorods and subsequent pyrolysis process. The chemical compositions of Mo₂C/Co/C composites indeed play a dominant role in tailoring their EM functions. It is revealed that conductivity loss, polarization loss, and magnetic loss are together responsible for the attenuation of EM energy. Although the involvement of Mo₂C nanoparticles weakens magnetic loss capability to some extent, there will be a positive reinforcement in conductivity loss through the synergistic effects among different components. In addition, Mo₂C nanoparticles can further provide considerable dipole orientation polarization and interfacial polarization. Among these ternary composite, MCC-50 with 30.9% of carbon, 53.6% of Mo₂C, and 15.5% of Co, exhibits the best EM absorption performance, whose reflection loss intensity and qualified response bandwidth are superior to those of most carbide-based composites in previous studies. These results suggest that the rational integration of components with different loss mechanisms will be an effective pathway to enhance EM absorption.