Preparation And Application Of Ferrite-sulphide And RGO Composite Nanomaterials

The development of high-efficiency microwave absorbing materials is the most important way to solve electromagnetic pollution.In recent years,the research of microwave absorbing materials mainly focuses on two directions:one is to combine the different materials to adjust electromagnetic parameters in order to enhance absorbing performance,and the other is to adjust the morphological structure of the materials and enhance the absorbing properties through the control of surface interface properties.This article explores the two research mechanisms in depth.Firstly,by adding to the reduced graphene oxide,the reduced graphene oxide is combined with the ferrite material to adjust the electromagnetic parameters of the material and enhance the microwave absorption characteristics of the material.Secondly,the ferrite/sulfide physical properties were studied by constructing the structure of ferrite/sulfide composite.In addition,the absorbing properties of sulfide composites were analyzed and the effects of core-shell structure on microwave absorption properties were investigated.The specific research contents are as follows:1.Preparation of rGO/SFO/CFO composite nanomaterials and investigation of their absorbing properties.Firstly,Sm3Fe5O12/CoFe2O4(SFO/CFO)composite nanomaterials were prepared by microwave hydrothermal method and combined with graphene oxide(GO)prepared by modified Hummers method to obtain ternary composite nanomaterials rGO/Sm3Fe5012/CoFe2O4(rGO/SFO/CFO).Raman and XPS tests indicate that graphene oxide(GO)is reduced to reduced graphene oxide(rGO)in the hydrothermal reaction.SEM results show that SFO/CFO nanoparticles are uniformly distributed on rGO nanosheets,and the introduction of rGO with excellent dielectric properties can overcome the shortcomings of poor dielectric properties of magnetic SFO/CFO nanoparticles.In addition,the permeability of the ternary composite is controlled by changing the mass ratio of SFO to CFO,in order to obtain an excellent impedance matching ratio between dielectric constant and permeability.Finally,the optimal reflection loss of the RGO/SFO/CFO composite nanomaterial with a SFO/CFO mass ratio of 1:3 is-73.71 dB,and the maximum bandwidth is up to 7.12 GHz.The excellent absorbing performance shows that it is a feasible idea to enhance the microwave absorption performance of the sample by changing the magnetic permeability of the material and the prepared rGO/SFO/CFO composite is an outstanding EMW absorbing material.2.The regulation of the morphology,structure and physical properties of barium ferrite by KOH.In this paper,a series of rare earth samarium ferrite materials were synthesized by hydrothermal method.The modification and structure of potassium hydroxide(KOH)were studied to study the effective regulation of KOH on the structure and physical properties of the synthesized barium ferrite.The physical properties of the synthesized samples showed that the addition of KOH and the change of the addition amount greatly affected the particle morphology,microstructure and material properties of the synthesized samples.This work further confirmed the influence of the amount of raw materials added and the manner of addition on the physical properties and microstructure of the material in ferrite synthesis.3.Preparation of CoS2/MoS2/rGO composite nanomaterials and their microwave absorption properties.CoS2/MoS2 nanoparticles with core-shell structure were successfully prepared by microwave hydrothermal method with the help of surfactants.The electrostatic interaction between CTAB cationic surfactant and the negative charge of GO is used to combine the core-shell structure of CoS2/MoS2 nanoparticles with GO.Finally,the microwave hydrothermal method is used to successfully prepare CoS2/MoS2/rGO composite.The results of SEM and Mapping show that the prepared CoS2/MoS2 composite nanomaterials have a core-shell structure which is favorable for microwave absorption,and rGO successfully coats the core-shell structure of CoS2/MoS2 nanoparticles.The microwave absorption performance shows that the optimal reflection loss of CoS2/MoS2/rGO is-58.0 dB and the maximum effective bandwidth is up to 6.24 GHz.The excellent absorbing performance shows that the multiple relaxation process caused by the core-shell structure is beneficial to the improvement of the absorbing properties of the material,which provides a good idea for constructing new absorbing materials.