Synthesis And Electromagnetic Wave Absorption Performance Of MoSe₂-based Composites

The development of electromagnetic wave absorption（EMA）materials with multi-band absorption characteristics provides an effective strategy to prevent and control electromagnetic radiation pollution.Traditional ferrite absorption materials have disadvantages such as high density,easy oxidation and single loss mechanism,which seriously hinder their development in the field of EMA materials.Therefore,the preparation of multi-band EMA materials with low density,wide absorption band and multiple loss has attracted widespread attention from researchers.As a typical two-dimensional（2D）structural material,Mo Se₂ has many advantages such as large specific surface area,numerous defects,and abundant 2D molecular networks,which has become a research hotspot of EMA materials.Mo Se₂-based composites prepared by Mo Se₂ and other materials can overcome the disadvantages of weak conductivity and poor impedance matching of single Mo Se₂,and promote the practical application of Mo Se₂ in the field of EMA materials.In this paper,Mo Se₂ and Mo Se₂-based composites were synthesized by solvothermal method,and the EMA properties and mechanism were discussed.The main research contents are as follows:（1）Mo Se₂,Mo Se₂@reduced graphene oxide（Mo Se₂@r GO）and Mo Se₂@r GO@Mo O₂ with dielectric loss property of EMA materials were successfully prepared by solvothermal synthesis strategy.EMA performance of Mo Se₂-based composites can be effectively regulated by adjusting the structure and the ratio of each component.Due to the characteristics of numerous defects,abundant conductive networks and good impedance matching,Mo Se₂-based composites show good attenuation ability to incident electromagnetic energy.（2）EMA properties of Mo Se₂ and its composites are systematically studied.Compared with the single Mo Se₂ absorption material（-16.0 d B,2.0 GHz）,Mo Se₂-based composite has the advantages of strong reflection loss（-56.9 d B）and wide effective absorption band（4.1 GHz）.Due to the enhanced dielectric loss and impedance matching characteristics,the optimized Mo Se₂-based composite exhibits multi-band absorption characteristics（S,X,and Ku bands）.（3）EMA mechanism of Mo Se₂ and Mo Se₂-based composites had analyzed in detail.The accumulation of Mo Se₂ nanosheets can be effectively prevented by combining Mo Se₂ with r GO.Increasing the specific surface area of the material realized the advantage of lightweight of the EMA materials.The introduction of dielectric materials（r GO,Mo O₂）can effectively adjust the dielectric constant of the material while successfully constructing the three-dimensional conductance network,thus enhancing the dielectric loss and adjusting the impedance matching characteristics of the material.In this paper,by adjusting the morphology of Mo Se₂-based composite and the ratio of each component,EMA performance of the composite was effectively adjusted,thus achieving the high efficiency of multi-band wave absorbing.The successful preparation of highly efficient Mo Se₂-based absorption materials provides a new method and idea for the preparation of EMA materials with multi-band absorbing characteristics.