3D Nest-Like Architecture of Core–Shell CoFe₂O₄@1T/2H-MoS₂ Composites with Tunable Microwave Absorption Performance

Abstract

As a promising microwave absorber filler, molybdenum disulfide (MoS 2 ), because of the unique structure, high electrical conductivity, and polarization effect, is receiving more and more interest. Developing MoS 2 -based composites with specific structure and morphology is a hot top in the field of microwave absorbers, because of its strong multiple scattering and reflecting for microwaves as well as its unique interfacial characteristics. Now, with a facile solvothermal method, a novel core−shell CoFe 2 O 4 @1T/2H-MoS 2 composite is synthesized, where the CoFe 2 O 4 nanospheres are entirely embedded in a special three-dimensional (3D) nest-like 1T/2H phase MoS 2 . Notably, in comparison with superparamagnetic CoFe 2 O 4 nanospheres, the coercivities of as-synthesized CoFe 2 O 4 @1T/2H-MoS 2 composites greatly increase. Here, 1T/2H-MoS 2 exhibits ferromagnetism superimposed onto large diamagnetism. It is noted that, by adjusting the content of 1T/2H-phase MoS 2 , the microwave absorption performance of as-synthesized composites can be effectively tuned. The combination of 1T/2H-MoS 2 with CoFe 2 O 4 helps to adjust the permittivity and optimize the impedance matching of the composites. Impressively, a minimum reflection loss (RL min ) of −68.5 dB for the as-synthesized composites with a thickness of 1.81 mm is gained at 13.2 GHz; meanwhile, a broad effective bandwidth of 4.56 GHz ranged from 13.2 to 17.76 GHz is achieved at 1.6 mm. Further, the overall effective bandwidth (RL < −10 dB) is obtained up to 14.5 GHz from 3.5 to 18.0 GHz, covering more than 90% of the measured frequency range. The high microwave absorption performance is ascribed to the special structure design with the core of magnetic CoFe 2 O 4 nanospheres and the shell of dielectric nest-like 1T/2H-MoS 2 as well as their appropriate impedance matching. From the perspective of basic research and practical microwave application, this study provides another feasible and effective pathway to design novel MoS 2 -based magnetic/dielectric microwave absorbers.

Lotus Leaf-Derived Gradient Hierarchical Porous C/MoS2 Morphology Genetic Composites with Wideband and Tunable Electromagnetic Absorption Performance

“…2 b and S1a. Three peaks at about 280, 360, and 408 cm −1 , originating from E 1g , E 2g 1 , and A 1g Raman vibrational modes of 2H–MoS 2 , respectively, are detected in the composites LCMS-600, LCMS-700, and LCMS-800 [ 26 ]. In addition, two distinct peaks located at 1360 and 1580 cm −1 are the D and G bands of the carbon phase, respectively [ 27 ].…”

MoS2-Decorated/Integrated Carbon Fiber: Phase Engineering Well-Regulated Microwave Absorber

“…The octahedral coordination of 1T (triangle)-MoS 2 structure has metallic property that the stacking sequence is AbC, AbC, and belongs to metastable structure, but it shows a high electrical conductivity [ 26 ]. Therefore, combined with above advantages, the mixed phase MoS 2 (1T@2H-MoS 2 ) would have the great application potential in the field of microwave absorption [ 27 ].…”

Defect Induced Polarization Loss in Multi‐Shelled Spinel Hollow Spheres for Electromagnetic Wave Absorption Application

“…Thus, it is understandable that the non‐magnetic substance would display diamagnetic behavior. [ 44 ] After heating treatment, specimens possess ferromagnetic curves due to ferromagnetic nature of spinel NiCo 2 O 4 that is formed after calcination. Though the magnetization shows a decrease tendency with elevating calcination temperature, the maximum magnetization of NCO‐500 is only 3.78 emu g −1 .…”