MoS-Coated MOF-Derived Hollow Heterostructures for Electromagnetic Wave Absorption.

Structural design constitutes one of the crucial approaches for augmenting the wave-absorbing capacity of electromagnetic wave (EMW) absorbers, and the incorporation of cavity structures represents a typical methodology therein. In this work, the MoS-coated metal-organic framework (MOF)-derived Hollow-MoS@CNS@CoS composite materials (HCNSs) were prepared by combining tannic acid-protected etching, carbonization, and hydrothermal methods. Especially, HCNS700, which possessed both a hollow structure and a layered heterogeneous structure, demonstrated excellent EMW absorption properties. It attained an optimal reflection loss of -63.63 dB at 16.4 GHz and -58.97 dB at 10.4 GHz, along with an extremely low thickness. In addition, the radar cross section simulation demonstrated that HCNS700 possessed excellent electromagnetic stealth capabilities. Its excellent performance is put down to the multiple loss mechanisms brought by the special structure, including multiple scattering of EMW caused by the hollow structure, interface polarization caused by the heterogeneous interfaces of MoS, CoS, and the carbon matrix, dipole polarization caused by element doping and defects, and optimization of impedance matching by MoS. This research offers a novel concept for the design of EMW-absorbing materials with hollow heterogeneous layered structures.