Hollow Co0.85Se@MoSe2 with Core–Sheath Structures Derived from Co Microchains for High Efficiency Electromagnetic Wave Absorption

Hollow and hierarchical structures are the desirable features for high-performance electromagnetic wave absorbing (EWA) materials. In this study, Co microchains were used as a matrix and a layer of MoSe2 nanosheets and nanospheres was loaded onto their surface through a one-step hydrothermal reaction. During this process, Co cations migrated from the inside to the outside of the nanowire and combined with Se anions to form hollow Co0.85Se microchains and the MoSe2 on the surface contributed to a hierarchical structure. The prepared Co0.85Se@MoSe2 composites showed dielectric and magnetic losses simultaneously, achieving a minimum reflection loss (RLmin) of −42.6 dB and an effective absorbing bandwidth (EAB) of 10 GHz (6.8–10.6 and 11.8–18 GHz) at the thickness of 2.3 mm. Co0.85Se@MoSe2 microchains were successfully synthesized for the first time using a cost-effective and simple solvothermal reaction. This work sheds light on the large-scale synthesis of Co-based microchains as well as a promising EWA material with a specific structure and multiple loss modes.