1D/2D CoTe_(2)@MoS_(2)composites constructed by CoTe_(2)nanorods and MoS_(2)nanosheets for efficient electromagnetic wave absorption

Rational design of the components and microstructure is regarded as an efficacious strategy for the high-performance electromagnetic wave absorbing(EMWA)materials.Herein,the CoTe_(2)@MoS_(2)nanocomposites with CoTe_(2)nanorods and MoS_(2)nanosheets were synthesized via a hydrothermal method.The microstructure and composition of the samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).The CoTe_(2)@MoS_(2)composite was composed of stacked CoTe_(2)as the core and intertwined MoS_(2)nanosheets as the shell.The electromagnetic parameters of the CoTe_(2)@MoS_(2)composites were investigated by vector network analyzer(VNA).The EMWA property of the composite showed a trend of first increasing and then decreasing with the increasing content of MoS_(2).When the mass ratio of MoS_(2)and CoTe_(2)was 1:1,the CoTe_(2)@MoS_(2)composite exhibited the minimum reflection loss value of-68.10 dB at 4.71 GHz,and the effective absorption bandwidth value might reach 4.64 GHz(13.08-17.72 GHz)at a matching thickness of 1.60 mm with filler loading of 50 wt.%.The extraordinary EMWA property was attributed to the optimized impedance matching,multiple scattering and reflections,dipole polarization,conductive loss,and interfacial polarization.Therefore,the present approach to the design of microstructure and interface engineering offers a crucial way to construct high-performance EMW absorbers.

MoS_(2) wrapped MOF-derived N-doped carbon nanocomposite with wideband electromagnetic wave absorption

Designing electromagnetic wave absorption(EMWA)materials with wide bandwidth,strong absorption,and light weight is still a great challenge for practical applications.Herein,the novel nitrogen doped carbon(NDC)/MoS_(2) composite with rationally designed composition and structure was developed.The NDC particles were introduced into MoS_(2) nanosheets through the calcination of ZIF-8 precursor and consequent hydrothermal process.A series of characterizations were carried out to investigate the physical properties of the as-prepared nanocomposites.The NDC particles exhibited the shape of rhombic dodecahedron with the size of about 500 nm,which were decorated on flower-shaped MoS_(2) with the size of about 3μm.With the increasing NDC content,the absorbing properties of NDC/MoS_(2) composites increased firstly and then decreased.The features of NDC/MoS_(2) composite including interconnected porous structure,nitrogen dopant,and appropriate electrical conductivity gave rise to the polarization,multiple reflection,multiple scattering,and impedance matching,resulting in the outstanding EMWA performance.With a filler loading ratio of 30 wt.%,the optimized EMWA property can be achieved when the mass ratio of NDC to MoS_(2) was adjusted to be 1:1.At a coating thickness of 3.0 mm,the effective EMWA bandwidth(<−10 dB)reached 6.08 GHz(8.56–14.64 GHz).These satisfactory achievements provide a way for the reasonable design of high-performance EMWA and new ideas for future research on wideband EMWA.