Hierarchical Magnetic Network Constructed by CoFe Nanoparticles Suspended Within “Tubes on Rods” Matrix Toward Enhanced Microwave Absorption  

作　　者：Chunyang Xu Lei Wang Xiao Li Xiang Qian Zhengchen Wu Wenbin You Ke Pei Gang Qin Qingwen Zeng Ziqi Yang Chen Jin Renchao Che 

机构地区：[1]Laboratory of Advanced Materials,Department of Materials Science and Collaborative Innovation Center of Chemistry for Energy Materials(iChem),Fudan University,Shanghai 200438,People’s Republic of China

出　　处：《Nano-Micro Letters》2021年第3期80-94,共15页纳微快报（英文版）

基　　金：This work was supported by the Ministry of Science and Technology of China(973 Project No.2018YFA0209102);the National Natural Science Foundation of China(11727807,51725101,51672050,61790581).

摘　　要：Hierarchical 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 frameworksbased 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.

关 键 词：Hierarchical core-shell MOF-based composites CoFe nanoparticles Magnetic network Microwave absorption 

分 类 号：TB383.1[一般工业技术—材料科学与工程]