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Enhanced microwave absorption performance from abundant polarization sites of ZnO nanocrystals embedded in CNTs via confined space synthesis

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Abstract

Dielectric composites constructed using carbon and metal oxides have become a hot research topic; however, the strategy to strengthen the coupling of components still needs to be optimized to enhance dielectric loss. Herein, ultra-fine ZnO derived from ZIF-8 was uniformly distributed and tightly embedded in multi-wall carbon nanotubes (C–ZnO@CNTs) via a novel confined space synthesis. Due to the presence of a polypyrrole coating, ZnO nanocrystals could be formed in the space of the original polyhedron and inserted into the CNTs, promoting the generation of polarized CNTs and providing abundant polarization centers on the CNTs. The composites exhibited superior microwave absorption capacity with a reflection loss value of up to −48.2 dB at 6.0 GHz, and the effective bandwidth reached 14.9 GHz by adjusting their thickness. According to the geometric phase analysis, the strain driven by the tight-coupling between ZnO–CNTs was confirmed to exist in the interfaces, boosting their inherent electromagnetic properties. The improved dielectric loss was caused by the strong interfacial polarization among ZnO–ZnO or ZnO–CNTs and the conductive loss among intertwined CNTs network, as revealed by electron holography. Therefore, the overall electrical properties could be improved by the polarized C–ZnO@CNTs with high electron conductivity. The confined space strategy may have promising potential for the synthesis of new composites of polarized carbon materials tightly coupled with metal oxides nanocrystals.

Graphical abstract: Enhanced microwave absorption performance from abundant polarization sites of ZnO nanocrystals embedded in CNTs via confined space synthesis

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Publication details

The article was received on 13 Sep 2019, accepted on 01 Nov 2019 and first published on 04 Nov 2019


Article type: Paper
DOI: 10.1039/C9NR07895A
Nanoscale, 2019, Advance Article

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    Enhanced microwave absorption performance from abundant polarization sites of ZnO nanocrystals embedded in CNTs via confined space synthesis

    X. Li, L. Wang, W. You, X. Li, L. Yang, J. Zhang, M. Wang and R. Che, Nanoscale, 2019, Advance Article , DOI: 10.1039/C9NR07895A

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