Hollow core–shell structure Co/C@MoSe2 composites for high-performance microwave absorption

• Hollow core–shell structure Co/C@MoSe 2 was constructed to study the effect on electromagnetic wave absorption performance. • Co/C@MoSe 2 achieves a high electromagnetic wave absorption, with an effective absorption bandwidth of 5.1 GHz and a minimum reflection loss of −42 dB(2.5 mm). • The impedance matching of the composite was successfully regulated with the increasing doping amount of MoSe 2 . • Composites realize the synergistic loss of electromagnetic waves caused by dielectric loss, magnetic loss and conductive loss. To address an increasingly serious electromagnetic radiation problem and the urgent need to develop lightweight, high-efficiency, and strong-attenuation electromagnetic wave absorbing (EMA) materials, a hollow core–shell Co/C@MoSe 2 composite structure was prepared. Flower-like MoSe 2 was wrapped around the surface of Co/C composites after a hydrothermal reaction. The introduction of MoSe 2 and the designed hollow core–shell structure was beneficial for optimizing the electromagnetic characteristics of the composites. Owing to the magnetism of Co/C composites after high-temperature treatment, the composite materials were capable of magnetic dissipation. The introduced multiple-attenuation mechanisms, such as dielectric loss, magnetic loss, and conductive loss, contributed greatly to the incident electromagnetic wave attenuation. Among them, Co/C@MoSe 2 -4 exhibited excellent electromagnetic wave absorption performance. When the matching thickness was 2.5 mm, the minimum reflection loss was −42 dB, and the effective absorption bandwidth was 5.1 GHz. This work provided a smart strategy for electromagnetic wave absorbers designing and commerical application.