15August2020

Nano-Micro Letters

MOF-Derived Ni1-xCox@Carbon with Tunable Nano-Microstructure as Lightweight and Highly Efficient Electromagnetic Wave Absorber

Lei Wang1, Mengqiu Huang1, Xuefeng Yu1, Wenbin You1, Jie Zhang1, Xianhu Liu2, Min Wang1, Renchao Che1, *

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Nano-Micro Lett. (2020) 12: 150

First Online: 15 July 2020 (Article)

DOI:10.1007/s40820-020-00488-0

*Corresponding author. E-mail: rcche@fudan.edu.cn (Renchao Che)

 

Abstract

 


Toc

Intrinsic electric-magnetic property and special nano-micro architecture of functional materials have a significant effect on its electromagnetic wave energy conversion, especially in the microwave absorption (MA) field. Herein, porous Ni1-xCox@Carbon (Ni@C) composites derived from metal-organic framework (MOF) were successfully synthesized via solvothermal reaction and subsequent annealing treatment. Benefiting from the coordination, carbonized bimetallic Ni-Co-MOF maintains its initial skeleton and transforms into magnetic-carbon composites with tunable nano-micro structure. During the thermal decomposition, generated magnetic particles/clusters act as a catalyst to promote the carbon sp2 arrangement, forming special core-shell architecture. As the Nickel content increases, Ni@C composites exhibit enhanced saturation magnetization, conductivity, and electromagnetic parameters, which is necessary to the high-performance MA ability. Therefore, pure Ni@C microspheres display strong MA behaviors than other Ni@C composites. Surprisingly, magnetic-dielectric Ni@C composites possess the strongest reflection loss value -59.5 dB and the effective absorption frequency cover as wide as 4.7 GHz. Meanwhile, the MA capacity also can be boosted by adjusting the absorber content from 25% to 40%. Magnetic–dielectric synergy effect of MOF-derived Ni@C microspheres was confirmed by the off-axis electron holography technology making a thorough inquiry in the MA mechanism.


 

Keywords

Metal-organic frameworks, Polarization, Magnetic coupling, Microwave absorption, Electromagnetic parameters

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