Preparation Of MSe₂@MoSe₂ (M=Fe,Co,Ni) And Study Of Its Electromagnetic And Microwave Absorption Propertie

As the 5G era continues to develop rapidly and high-frequency communication devices are widely used,the development of high-performance microwave absorbing materials has become a popular topic in recent years due to the expansion of electromagnetic interference problems and their potential applications in the military industry.Through extensive literature research and experimental studies,it was found that single-component absorbing materials have certain limitations and limited innovation,so we chose to study multi-component composite absorbing materials.Both magnetic and dielectric materials have certain advantages as a single material,so these two materials are compounded to complement each other,i.e.,magnetic ferrite（Fe₃O₄,CoFe₂O₄ and NiFe₂O₄）is compounded with transition metal sulfide（MoSe₂）,and finally MSe₂@MoSe₂（M=Fe,Co,Ni）with flower-like core@shell structure were prepared multicomponent nanocomposites.The details of the paper are as follows.（1）In order to effectively utilize the unique properties of layered transition metal dichalcogenide and the attractive morphology of hierarchical flower for the attenuation of electromagnetic wave,herein,high-efficiency flower-like core@shell structure FeSe₂@MoSe₂ nanocomposites were firstly synthesized through a simple in situ hydrothermal reaction on the surfaces ofFe₃O₄ nanoparticles with the adequate amounts of Mo and Se sources.The obtained results indicated that the designed flower-like core@shell structure FeSe₂@MoSe₂ nanocomposites with the filler loadings of 30 wt%and 40 wt%presented the optimal reflection loss（RLmin）value of-59.87 dB at 11 GHz with a matching thickness of 3.10 mm and-60.53 dB at 13.52 GHz with a matching thickness of 2.47 mm.And their corresponding effective frequency bandwidth（f_b）values were up to 10.0 GHz with a thickness of 3.66 mm and 6.00 GHz with a thickness of 2.12 mm,respectively.It was worth pointing out that the as-prepared flower-like FeSe₂@MoSe₂ nanocomposite with filler loading of 30 wt%could simultaneously present very extraordinary electromagnetic wave absorption capabilities and broad absorption bandwidth with the very thin matching thicknesses,which was desirable for high-efficient microwave absorbers.Therefore,a simple and effective strategy was proposed to produce flower-like core@shell structure MoSe₂-based nanocomposites,which could be applied as the very desirable candidates for high-performance microwave absorption materials.（2）In this work,we proposed a scheme to exquisitely design and selectively synthesize the core@shell structured MSe₂/FeSe₂@MoSe₂（M=Co,Ni）flower-like multicomponent nanocomposites（MCNCs）through a simple two-step hydrothermal reaction on the surfaces of MFe₂O₄ nanospheres with the certain amounts of Mo and Se sources.With increasing the amounts of Mo and Se sources,the obtained core@shell structured MSe₂/FeSe₂@MoSe₂（M=Co,Ni）MCNCs with the enhanced content of MoSe₂ and improved flower-like geometry morphology could be produced in large-scale.The obtained results revealed that the as-prepared samples displayed the improved comprehensive microwave absorption properties（CMAPs）with the increased amounts of Mo and Se sources.The as-prepared CoSe₂/FeSe₂@MoSe₂ and NiSe₂/FeSe₂@MoSe₂ MCNCs with the well-defined flower-like morphology could simultaneously presented the outstanding CMAPs in terms of strong absorption capability,wide absorption bandwidth and thin matching thicknesses,which mainly originated from the conduction loss and flower-like geometry morphology.Therefore,the findings not only developed the very desirable candidates for high-performance microwave absorption materials,but also paved a new way for optimizing the CMAPs through tailoring morphology engineering.