Heterostructure design of MOFs derived Co9S8/FeCoS2/C composite with efficient microwave absorption and waterproof functions

Abstract

• A hierarchical Co9S8/FeCoS2/C composite has been designed. • Benefiting from the enhanced polarization loss, optimized synergistic effect, and multiscale EMW dissipation paths, Co9S8/FeCoS2/C composite exhibits superior EMW absorption. • The bouquet-like architecture formed by many nanorods produces a large number of void spaces and interfaces. • The obtained Co9S8/FeCoS2/C composite shows a broad effective bandwidth of 5.1 GHz at a thickness of 2 mm. At present, the problem of electromagnetic wave (EMW) pollution is critical, and the design of high-performance absorbers is of great significance. Based on the synergy between dielectric and magnetic losses, and between multicomponents in heterostructures, the development of light-weight absorbers with a strong absorption capability and multiple scattering is a promising strategy to achieve high-performance absorbers. In this work, CoFe-MOF precursors with a bouquet-like structure were prepared via the hydrothermal method, and Co 7 Fe 3 /C and Co 9 S 8 / FeCoS 2 /C composites were obtained through a carbonization and sulfuration treatment during the high-temperature pyrolysis process, respectively. The experimental and theoretical results show that the Co 9 S 8 /FeCoS 2 /C composite has a better EMW absorption performance, and its optimal reflection loss (RL) value is -53.9 dB at a low filler loading of 20 wt.%, which is due to the S doping that enhances the interface polarization relaxation process and improves the impedance matching characteristics. Moreover, the Co 9 S 8 /FeCoS 2 /C composite can be as candidates of high-efficiency absorbers in extreme application environments.