scholarly journals Facile Synthesis of Cobalt-Doped Porous Composites with Amorphous Carbon/Zn Shell for High-Performance Microwave Absorption

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 330 ◽  
Author(s):  
Qilei Wu ◽  
Huihui Jin ◽  
Bin Zhang ◽  
Siqi Huo ◽  
Shuang Yang ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Amorphous Carbon ◽  
Porous Carbon ◽  
High Performance ◽  
Impedance Matching ◽  
Broad Band ◽  
Matching Condition ◽  
Carbon Composite ◽  
Absorption Capacity ◽  
Zeolitic Imidazolate Framework

A facile method for the preparation of microwave absorbers with low density, high microwave absorptivity, and broad band is of paramount importance to the progress in practical application. Herein, commonly-used metal organic frameworks (MOFs) prepared just by mechanical stirring in methanol at room temperature were chosen as sacrificial templates to synthesize porous carbon composites with tunable dielectric and magnetic properties. With the replacement of Co atoms on the surface of zeolitic imidazolate framework-67 (ZIF-67) by Zn atoms, a Co-doped porous carbon composite with a low-dielectric amorphous carbon/Zn shell was constructed after annealing, leading to excellent impedance matching condition. Consequently, the as-obtained composite (Co/C@C-800) shows marvelous microwave absorption properties with an absorption capacity of −43.97 dB and a corresponding effective absorption bandwidth of 4.1 GHz, far exceeding that of the traditional porous carbon and composites directly derived from ZIF-67. The results provide a convenient way to modify MOFs for enhanced microwave absorption materials from the synergy of dielectric and magnetic losses.

Synthesis of Ultrathin MnO2 Nanosheets/Bagasse Derived Porous Carbon Composite for Supercapacitor with High Performance

2019 ◽  
Vol 48 (5) ◽  
pp. 3026-3035 ◽  
Author(s):  
Botong Zhou ◽  
Yanwei Sui ◽  
Jiqiu Qi ◽  
Yezeng He ◽  
Qingkun Meng ◽  
...  
Keyword(s):  
Porous Carbon ◽  
High Performance ◽  
Carbon Composite ◽  
Mno2 Nanosheets

Facile sonochemical assisted synthesis of a hybrid red–black phosphorus/sulfonated porous carbon composite for high-performance supercapacitors

2020 ◽  
Vol 56 (52) ◽  
pp. 7096-7099 ◽  
Author(s):  
Arthi Gopalakrishnan ◽  
Sushmee Badhulika
Keyword(s):  
Porous Carbon ◽  
High Performance ◽  
Low Cost ◽  
Carbon Composite ◽  
Black Phosphorus ◽  
Supercapacitor Application ◽  
Novel Synthesis

Low-cost novel synthesis of a hybrid red–black phosphorus/sulfonated porous carbon composite for supercapacitor application.

A Se-hollow porous carbon composite for high-performance rechargeable K–Se batteries

2019 ◽  
Vol 6 (8) ◽  
pp. 2118-2125 ◽  
Author(s):  
Xianglong Huang ◽  
Wei Wang ◽  
Jianhua Deng ◽  
Wei Gao ◽  
Dingyu Liu ◽  
...  
Keyword(s):  
Porous Carbon ◽  
High Performance ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Hollow Carbon

In this study, a novel hollow carbon matrix was designed and prepared using a facile NaCl crystal template for the effective encapsulation of Se.

High performance sodium storage of Fe-doped mesoporous anatase TiO2/amorphous carbon composite

2016 ◽  
Vol 666 ◽  
pp. 254-261 ◽  
Author(s):  
Yanqing Lai ◽  
Wenwen Liu ◽  
Jie Li ◽  
Kai Zhang ◽  
Furong Qin ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
High Performance ◽  
Carbon Composite ◽  
Anatase Tio2 ◽  
Sodium Storage

scholarly journals A Fe/Fe3O4/N-carbon composite with hierarchical porous structure and in situ formed N-doped graphene-like layers for high-performance lithium ion batteries

2015 ◽  
Vol 44 (10) ◽  
pp. 4594-4600 ◽  
Author(s):  
Yao Li ◽  
Qing Meng ◽  
Shen-min Zhu ◽  
Zeng-hui Sun ◽  
Hao Yang ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Porous Carbon ◽  
High Performance ◽  
Lithium Ion ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Hierarchical Porous Structure ◽  
Hierarchical Porous ◽  
Doped Graphene

A Fe/Fe3O4/N-carbon composite consisting of a porous carbon matrix containing a highly conductive N-doped graphene-like network and Fe/Fe3O4 nanoparticles was prepared.

scholarly journals Enhanced Microwave Absorption of Quartic Layered Epoxy-Mwcnt Composite for Radar Applications

2017 ◽  
Vol 26 (4) ◽  
pp. 096369351702600 ◽  
Author(s):  
M. K. Naidu ◽  
K. Ramji ◽  
B. V. S. R. N. Santhosi ◽  
TC Shami ◽  
Himangshu B Baskey ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Free Space ◽  
Impedance Matching ◽  
Wave Theory ◽  
Matching Condition ◽  
Permittivity And Permeability ◽  
Carbon Nano Tubes ◽  
Radar Absorbing Structure ◽  
Space Measurement

In this paper we presented the electromagnetic analysis of multilayered Radar Absorbing Structure (RAS) composed of Multi-Wall Carbon Nano Tubes (MWCNTs) with different weight percentages. The complex permittivity and permeability of MWCNT/epoxy composites with different wt% are analysed and the microwave absorbing characteristics are evaluated. The permittivity and permeability of MWCNT composites increased with increase in MWCNT concentration. Absorption properties like reflection loss of multilayered RAS are estimated analytically using electromagnetic wave theory for different layers and with different layer order based on impedance matching condition. The quartic layer MWCNT/epoxy composite achieves a better microwave absorption when compared to other multilayer RAS. The microwave absorption was attributed to dielectric loss of the material. The simulated quartic layer RAS is fabricated and validation of reflection loss is done experimentally using free space measurement technique. From free space measurement the minimum reflection loss in entire X-band is observed to be approximately −12 dB (95% of absorption), −15 dB (97% of absorption), with 3 GHz band width, −20 dB (99% of absorption) with 2 GHz bandwidth and maximum peak of - 44 dB at 11.5 GHz. Hence the composite material has great potential of application as highly efficient microwave absorber.

scholarly journals Two-Step Solvothermal Synthesis of (Zn0.5Co0.5Fe2O4/Mn0.5Ni0.5Fe2O4)@C-MWCNTs Hybrid with Enhanced Low Frequency Microwave Absorbing Performance

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1601 ◽  
Author(s):  
Pengfei Yin ◽  
Limin Zhang ◽  
Hongjing Wu ◽  
Xing Feng ◽  
Jian Wang ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Solvothermal Synthesis ◽  
Electromagnetic Waves ◽  
High Performance ◽  
Magnetic Loss ◽  
Synthesis Method ◽  
Low Frequency ◽  
Matching Condition ◽  
Shell Morphology ◽  
Nuclear Shell

In this study, the quaternary hybrid of (Zn0.5Co0.5Fe2O4/Mn0.5Ni0.5Fe2O4)@C-MWCNTs with high-performance in low frequency electromagnetic absorption was synthesized via a facile two-step solvothermal synthesis method. The physicochemical properties as well as electromagnetic parameters and microwave absorption performance were characterized by XRD, SEM, TEM, RS, TGA, and VNA, respectively. The results indicate a nuclear-shell morphology of this hybrid for amorphous carbon coated on the surface of Zn0.5Co0.5Fe2O4 and Mn0.5Ni0.5Fe2O4 mixed polycrystalline ferrites. In addition, the MWCNTs synchronously enwind in the nuclear-shell NPs to form a special cross-linking structure. The outstanding low frequency microwave absorption property is attributed to the synergistic effect of dielectric and magnetic loss, better impedance matching condition, and excellent attenuation characteristics of the as-prepared paramagnetic quaternary hybrid. Maximum RL of −35.14 dB at 0.56 GHz with an effective absorption bandwidth in the range of 0.27–1.01 GHz can be obtained with thickness of 5 mm. This hybrid exhibits superior low frequency microwave absorption properties compared with other ferrite-carbon nanocomposites. This investigation provides a new route to prepare suitable candidates for the absorption of electromagnetic waves in a low frequency band on account of its good performance and simple preparation process.

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