scholarly journals Boosting dual-interfacial polarization by decorating hydrophobic graphene with high-crystalline core-shell FeCo@Fe3O4 nanoparticle for improved microwave absorption

Carbon ◽  
2021 ◽  
Author(s):  
Yong Sun ◽  
Bo Zhou ◽  
Hongpeng Wang ◽  
Xia Deng ◽  
Juan Feng ◽  
...  
Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 166 ◽  
Author(s):  
Hui Liu ◽  
Guangzhen Cui ◽  
Ling Li ◽  
Zhi Zhang ◽  
Xuliang Lv ◽  
...  

Cobalt sulfide composites have exhibited great potential in terms of microwave absorption, owing to their low price, relatively high capacitance, and excellent electrocatalytic activity. Thus, a novel core-shell like structure comprising cobalt sulfide@polypyrrole (CoS@PPy) composite was synthesized by a facile solvothermal synthesis method and in situ polymerization. When coated by the heterostructure polypyrrole aerogel, CoS@PPy composite exhibited excellent microwave absorption properties with an optimal reflection loss (RL) of −41.8 dB at 6.96 GHz. Furthermore, the absorption bandwidth (RL < −10 dB) of 5.4 GHz could be reached at a coating thickness of 2.05 mm, probably attributing to the synergistic effect of good impedance matching, interfacial polarization, dipole polarization, and conductivity loss. Moreover, this work proposed a loss mechanism mode which probably occurred in the CoS@PPy composites. It was demonstrated that the CoS@PPy composite is a promising material in the field of electromagnetic wave absorption.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Chunyang Xu ◽  
Lei Wang ◽  
Xiao Li ◽  
Xiang Qian ◽  
Zhengchen Wu ◽  
...  

AbstractHierarchical magnetic-dielectric composites are promising functional materials with prospective applications in microwave absorption (MA) field. Herein, a three-dimension hierarchical “nanotubes on microrods,” core–shell magnetic metal–carbon composite is rationally constructed for the first time via a fast metal–organic frameworks-based ligand exchange strategy followed by a carbonization treatment with melamine. Abundant magnetic CoFe nanoparticles are embedded within one-dimensional graphitized carbon/carbon nanotubes supported on micro-scale Mo2N rod (Mo2N@CoFe@C/CNT), constructing a special multi-dimension hierarchical MA material. Ligand exchange reaction is found to determine the formation of hierarchical magnetic-dielectric composite, which is assembled by dielectric Mo2N as core and spatially dispersed CoFe nanoparticles within C/CNTs as shell. Mo2N@CoFe@C/CNT composites exhibit superior MA performance with maximum reflection loss of − 53.5 dB at 2 mm thickness and show a broad effective absorption bandwidth of 5.0 GHz. The Mo2N@CoFe@C/CNT composites hold the following advantages: (1) hierarchical core–shell structure offers plentiful of heterojunction interfaces and triggers interfacial polarization, (2) unique electronic migration/hop paths in the graphitized C/CNTs and Mo2N rod facilitate conductive loss, (3) highly dispersed magnetic CoFe nanoparticles within “tubes on rods” matrix build multi-scale magnetic coupling network and reinforce magnetic response capability, confirmed by the off-axis electron holography.


NANO ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. 1850125 ◽  
Author(s):  
Yun Li ◽  
Haifeng Cheng ◽  
Nannan Wang ◽  
Shen Zhou ◽  
Dongjin Xie ◽  
...  

To reduce the imbalance of impedance matching between the magnetic metal nanowires and free space, Fe/TiO2 core/shell nanowire arrays with different diameters were fabricated in the templates of anodic aluminum oxide membranes by electrodeposition. The influences of the microstructure on the microwave absorption properties of the Fe/TiO2/Al2O3 composites were studied by the transmission/reflection waveguide method. It was demonstrated experimentally that both the interfacial polarization and the diameter of the Fe/TiO2 core/shell nanowires have critical effects on the microwave absorption properties. We also investigated the angle dependence of the microwave absorption properties. Due to the interfacial polarization and associated relaxation, the Fe/TiO2/Al2O3 composites exhibited optimal microwave absorption properties when microwave propagation direction was accordant with the axis of the nanowires. Finally, we managed to obtain an optimal reflection loss of below [Formula: see text]10[Formula: see text]dB (90% absorption) over 10.2–14.8[Formula: see text]GHz, with a thickness of 3.0[Formula: see text]mm and the minimum value of [Formula: see text]39.4[Formula: see text]dB at 11.7[Formula: see text]GHz.


2021 ◽  
Vol 869 ◽  
pp. 159270
Author(s):  
Li He ◽  
Xun Li ◽  
Ruochen Dai ◽  
ZuTing Zhong ◽  
Yuchen Zhao ◽  
...  

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