Preparation Of Molybdenum Disulfide And Its Composites And Study On Their Microwave Absorption Properties

Modern electronic products have brought great convenience to people's lives,and the electromagnetic wave pollution generated by them has also brought great harm.The development of lightweight and highly efficient electromagnetic wave absorbing materials has become a research hotspot.The high specific surface area and polymorphism of molybdenum disulfide?MoS₂?make it have excellent electronic properties.Porous hollow spherical zinc oxide?ZnO?is light in weight,good in semiconductor properties,easy to achieve large-scale synthesis,and its pore structure can be adjusted to improve impedance matching.Barium ferrite(BaFe₁₂O₁₉),as a traditional absorbing material,has a high magnetic permeability at high frequencies.At the same time,BaFe₁₂O₁₉9 is inexpensive and easy to prepare,and has good thermal stability and chemical stability.Reduced graphene oxide?RGO?is light in weight,has a high specific surface area and electrical conductivity,and has various defects that contribute to the attenuation of electromagnetic waves.In this study,MoS₂ was compounded with ZnO,BaFe₁₂O₁₉9 and RGO in different mass ratios.The structure,composition and morphology of the samples were characterized by X-ray diffractometry?XRD?,Fourier transform infrared spectroscopy?FT-IR?,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,and X-ray photoelectron spectroscopy?XPS?,respectively.The magnetic properties and electromagnetic parameters of materials were tested by vibrating sample magnetometer?VSM?and vector network analyzer?VNA?.The factors affecting the absorbing properties of the materials and the absorbing mechanism were discussed.Research indicates:?1?MoS₂ was prepared by hydrothermal method using sodium molybdate?Na₂MoO₄·2H₂O?and thioacetamide?C₂H₅NS?as raw materials.The sample is in the shape of a flower ball with uniform particle dispersion and the particle size is about200-250 nm.The optimum matching thickness of MoS₂ is 2 mm,and the minimum reflection loss value occurs at a frequency of 11.2 GHz with a value of-12.7 dB and an effective absorption bandwidth of 4.16 GHz.?2?Porous hollow spherical ZnO was prepared by solvothermal method using glucose(C₆H₁₂O₆?6H₂O),zinc acetate?Zn?CH₃COO?₂?2H₂O?and urea?CO?NH₂?₂?as raw materials.The sample has a porous hollow sphere with a grain size of about 3?m.The ZnO/MoS₂ binary composites were prepared by hydrothermal method using ZnO and Na₂MoO₄·2H₂O and C₂H₅NS as raw materials.MoS₂ is supported on the surface of ZnO,and the morphology of the sample is obviously spherical and uniform.With the increase of MoS₂ content,the complex permittivity of binary composites increases.When the mass ratio of MoS₂ to ZnO is 30%,ZnO/MoS₂ composites have the best absorbing properties.When the matching thickness is 2.5 mm and the frequency is11.84 GHz,the minimum reflection loss value is-35.8 dB,and the effective absorption bandwidth is 10.24 GHz?7.76-18 GHz?.The frequency corresponding to the reflection loss peak decreases as the thickness increases.?3?Using barium nitrate?Ba?NO₃?₂?and ferric nitrate?Fe?NO₃?₃?as raw materials,sodium hydroxide?NaOH?as precipitant,and cetyltrimethylammonium bromide?CTAB?as surface agent,BaFe₁₂O₁₉9 was prepared by a coprecipitation method.BaFe₁₂O₁₉/MoS₂ binary composites were prepared by hydrothermal method using BaFe₁₂O₁₉9 and Na₂MoO₄·2H₂O and C₂H₅NS as raw materials.The spherical MoS₂ is supported on hexagonal BaFe₁₂O₁₉9 particles with a grain size between 200-250 nm.BaFe₁₂O₁₉9 is slightly agglomerated due to its magnetic properties.The saturation magnetization of the sample is enhanced as the content of BaFe₁₂O₁₉increases.When the mass ratio of BaFe₁₂O₁₉9 to MoS₂ is 15%,the material has the best absorbing properties.When the matching thickness is 3.9 mm and the frequency is7.44 GHz,the minimum RL value is-44.6 dB and the effective absorption bandwidth is 3.4 GHz.?4?Graphene oxide?GO?was prepared by modified Hummers method using natural graphite powder as raw material.BaFe₁₂O₁₉/MoS₂/RGO ternary composite was prepared by adding a certain amount of hydrazine hydrate on the basis of BaFe₁₂O₁₉/MoS₂ binary composite.Graphene has a lamellar structure and is coated on the surface of BaFe₁₂O₁₉/MoS₂ binary composite.When the mass ratio of RGO to BaFe₁₂O₁₉/MoS₂ binary composite is 6%,the sample has the best absorbing properties.When the matching thickness is 3.0 mm and the frequency is 15.04 GHz,the minimum reflection loss value is-47.9 dB and the effective absorption bandwidth is9.28 GHz.