scholarly journals High-efficiency microwave absorption performance of cobalt ferrite microspheres/multi-walled carbon nanotube composites

Author(s):  
Hongmei Liu ◽  
Min Zhang ◽  
Kang Hu ◽  
Xiangkai Kong ◽  
Qiang Li ◽  
...  
2019 ◽  
Vol 43 (24) ◽  
pp. 9574-9582 ◽  
Author(s):  
Jiamin Zhou ◽  
Gang Xu ◽  
Zewu Zhang ◽  
Hongyong Wang

A Cu2MoS4/MWCNT electrocatalyst with enhanced HER performance was synthesized for the first time, in which Cu2MoS4 nanosheets are intimately interlinked by MWCNTs.


2021 ◽  
Author(s):  
Hongmei Liu ◽  
Min Zhang ◽  
Kang Hu ◽  
Xiangkai Kong ◽  
Qiang Li ◽  
...  

Abstract In this article, spinel ferrite CoFe2O4 and multi-walled carbon nanotubes (MWCNTs) composites are constructed by a facile one-step solvothermal method. The pure phase of CoFe2O4 particles is confirmed by X-ray diffraction patterns. Microstructure analysis demonstrates that monodisperse CoFe2O4 microspheres are wound by MWCNTs. By the introduction of CNTs, there is a significant enhancement in the imaginary part of permittivity (ε″) with the composites. The champion microwave absorption performance can be achieved in the composites by the balance of complex permittivity and permeability. When the mass fraction of CNTs is 3%, a minimum reflection loss (RLmin) of the composites is as high as -46.65 dB at 14.4 GHz at a thin thickness of 1.5 mm, and the corresponding effective absorption bandwidth below − 10 dB reaches 4.91 GHz ranging from 12.41 to 17.32 GHz which covers almost the whole Ku band (12.0–18.0 GHz). In other words, this as-synthesized composites show the most outstanding specific RLmin of -31.1 dB•mm− 1. Such superior microwave absorption behaviors of CoFe2O4/CNTs originate mainly from multiple dielectric relaxation processes, enhanced impedance matching and magnetic loss, as well as the considerable interface between mesoporous CoFe2O4 hollow microspheres and CNTs, and thereby promoting microwave reflection and scattering within the samples. Our results indicate that as-fabricated CoFe2O4/CNTs composites can be a promising microwave absorbent integrating with thin thickness, strong absorption ability, and broad bandwidth absorption.


Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 832
Author(s):  
Edna X. Figueroa-Rosales ◽  
Javier Martínez-Juárez ◽  
Esmeralda García-Díaz ◽  
Daniel Hernández-Cruz ◽  
Sergio A. Sabinas-Hernández ◽  
...  

Hydroxyapatite (HAp) and hydroxyapatite/multi-walled carbon nanotube (MWCNT) composites were obtained by the co-precipitation method, followed by ultrasound-assisted and microwave radiation and thermal treatment at 250 °C. X-ray diffraction (XRD) confirmed the presence of a hexagonal phase in all the samples, while Fourier-transform infrared (FTIR) spectroscopy elucidated the interaction between HAp and MWCNTs. The photoluminescent technique revealed that HAp and the composite with non-functionalized MWCNTs present a blue luminescence, while the composite with functionalized MWCNTs, under UV-vis radiation shows an intense white emission. These findings allowed presentation of a proposal for the use of HAp and HAp with functionalized MWCNTs as potential materials for optoelectronic and medical applications.


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