Porous CoZn@NC skeletons supported NiCo2S4 nanorods for efficient electromagnetic wave absorption

Abstract

Bimetallic sulfides are promising in electromagnetic wave (EMW) absorption due to their moderate permittivity and high dielectric loss. However, the impedance mismatching and insufficient loss mechanism of bimetallic sulfides result in limited EMW absorption performance. Herein, bimetallic sulfide (NiCo2S4) nanorods were loaded onto nitrogen-doped carbon embedded with CoZn nanoparticles (CoZn@NC) derived from CoZn-based metal organic framework (CoZn-MOF) through simple hydrothermal and vulcanization processes. Importantly, during the vulcanization process, CoZn@NC undergoes structural reorganization and evolves into defect-rich porous nanosheets, which promotes dipole polarization and enhance EMW absorption ability. Additionally, the formed NiCo2S4 nanorods are tightly anchored on the porous CoZn@NC skeletons, forming a large number of heterostructures, and promoting interfacial polarization. In addition, the carbon nanotubes (CNTs) formed during the pyrolysis process of CoZn-MOF contribute to the conduction loss of the heterostructure and motivate dielectric loss. Therefore, CoZn@NC/NiCo2S4 heterostructures inherit excellent EMW absorption performance and obtain a reflection loss (RL) value of −32.53 dB at a matching thickness of 2.1 mm, while exhibiting an effective absorption bandwidth (EAB) of 4.1 GHz. Radar cross-sectional area (RCS) simulation shows that the potential of CoZn@NC/NiCo2S4 heterostructure in practical anti radar detection. This work puts up great potential for the development of advanced bimetallic sulfides-based EMW absorbers.