Co _xS _y/C@MoS₂ nanofibers: synthesis, characterization and microwave absorption investigation

Microwave absorbing materials have been widely studied and applied nowadays, but their loss mechanism, especially the correlation between attenuation characteristics and impedance matching, is still not clear. In this system comparative study, a novel metal − organic framework with the Co ions (Co-MOF), CoS₂@MoS₂ and Co_xS_y/C@MoS₂ nanofibers were prepared by hydrothermal reaction and heat treatment. All the samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and vector network analyzer (VSA). The results indicated that the minimum value of reflection loss (RL) for CoS₂@MoS₂-2 was − 31.12 dB and the corresponding bandwidth with effective attenuation (RL ≤ − 10 dB) was up to 2.36 GHz (from 7.0 to 10.6 GHz) at 2.7 mm. Compared with CoS₂@MoS₂ composites, the microwave absorbing performance (MAP) of Co_xS_y/C@MoS₂ nanofibers was enhanced obviously: the bandwidth with effective attenuation of Co_xS_y/C@MoS₂ was up to 3.67 GHz (7.24 GHz − 10.91 GHz) with coating thickness 3.7 mm, and the minimum RL value was − 41.32 dB. The enhanced MAP originated from the synergistic effect between polarization loss and conductive loss, which results from Co_xS_y, MoS₂ and introducing C, respectively.