Fabrication of polydopamine-coated ZIF-67 derived Co@CN/rGO composite with excellent electromagnetic wave absorption properties

Constructing a reasonable microstructure and component modulation is considered as an effective way to improve the absorption performance of the absorbents. Herein, a series of Co@CN/rGOs composites were obtained via simple pyrolysis of dopamine-coated ZIF-67 loaded graphene oxide (ZIF-67@PDA/GO) at a high temperature. The existence of rGO after thermal treatment effectively improved dielectric loss. The multiple heterogeneous interfaces between rGO and the carbon layers formed by the polydopamine pyrolysis facilitated the interfacial polarization and relaxation. As a result, with only 20 wt% filler content, the RLmin value of Co@CN/10%rGO reached -49.98 dB at 5.50 GHz (low frequency) with a thickness of 4.5 mm. The effective absorption bandwidth increased to 5.70 GHz (10.26-15.96 GHz) by adjusting the thickness to 2.3 mm. This work provides a facile method for the construction of multicomponent nonhomogeneous interfaces and offers a novel strategy for the design of efficient absorbents.