3D flower-like Co-based oxide composites with excellent wideband electromagnetic microwave absorption

Wang, Chenxi; Wang, Bingbing; Cao, Xin; Zhao, J. Z.; Chen, Lei; Shan, Liangang; Wang, Haonan; Wu, Guanglei

doi:10.1016/j.compositesb.2020.108529

Cited by 159 publications

(21 citation statements)

References 61 publications

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“…After a series of conversions, the energy gaps of four samples were 3.63, 3.58, 3.11, and 2.72 eV, respectively, showing a trend of narrowing. The ASGA directly presented the best electronic transition 39 among them, so it was much easier for electrons to transfer from the ground state to the excited state, and then the p−n heterojunction was also easily formed and crossed, which can enhance the gas sensitivity. In addition, the working temperature will also drop due to the narrow bandgap, where the barrier of electron transition became lower and the activation energy decreased, so there was no need to provide extra energy by heating.…”

Section: Resultsmentioning

confidence: 99%

Chemical Surface Adsorption and Trace Detection of Alcohol Gas in Graphene Oxide-Based Acid-Etched SnO₂ Aerogels

Yan

Liu

Shao

et al. 2021

ACS Appl. Mater. Interfaces

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An acidified SnO2/rGO aerogel (ASGA) is an attractive contributor in ethanol gas sensing under ultralow concentration because of the sufficient active sites and adsorption pores in SnO2 and the rGA, respectively. Furthermore, a p–n heterojunction is successfully constructed by the high electron mobility between ASP and rGA to establish a brand-new bandgap of 2.72 eV, where more electrons are released and the surface energy is decreased, to improve the gas sensitivity. The ASGA owns a specific surface area of 256.1 m2/g, far higher than SnO2 powder (68.7 m2/g), indicating an excellent adsorption performance, so it can acquire more ethanol gas for a redox reaction. For gas-sensing ability, the ASGA exhibits an excellent response of R a/R g = 137.4 to 20 ppm of ethanol at the optimum temperature of 210 °C and can reach a response of 1.2 even at the limit detection concentration of 0.25 ppm. After the concentration gradient change test, a nonlinear increase between concentration and sensitivity (S–C curve) is observed, and it indirectly proves the chemical adsorption between ethanol and ASGA, which exhibits charge transfer and improves electron mobility. In addition, a detailed energy band diagram and sensor response diagram jointly depict the gas-sensitive mechanism. Finally, a conversed calculation explains the feasibility of the nonlinear S–C curve from the atomic level, which further verifies the chemical adsorption during the sensing process.

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Section: Resultsmentioning

confidence: 99%

Chemical Surface Adsorption and Trace Detection of Alcohol Gas in Graphene Oxide-Based Acid-Etched SnO₂ Aerogels

Yan

Liu

Shao

et al. 2021

ACS Appl. Mater. Interfaces

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“…As can be seen from Figure 4 b, the survey spectrum of S2 contains C 1s, Co 2p and O 1s. Figure 2 exhibits high resolution Co 2p spectrum, where the peaks at 781.9 eV and 797.6 eV are attributed to Co 2+ 2p 3/2 and Co 2+ 2p 1/2 spectrums, respectively [ 50 , 51 ]. Two peaks at 785.5 eV and 803.6 eV are the satellite peaks that accompany the two peaks of Co 2+ .…”

Section: Resultsmentioning

confidence: 99%

In Situ Reduced Multi-Core Yolk–Shell Co@C Nanospheres for Broadband Microwave Absorption

et al. 2021

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The preparation of yolk–shell microwave absorption materials with low density and excellent microwave absorption property requires reasonable design and economical manufacture. In this study, an efficient strategy without any templates or reducing gases has been designed to fabricate multi-core yolk–shell Co@C nanospheres by high temperature carbonization. The results showed that Co3O4 was completely reduced by the carbon shell to metal cobalt at temperatures above 750 °C. This unique multi-core yolk–shell structure with shell of 600 nm and multiple cores of tens of nanometers can provide sufficient interface and space to reflect and scatter electromagnetic waves. At the same time, the metal cobalt layer and carbon layer provide magnetic loss ability and dielectric loss ability, respectively, making the composite show good wave absorption performance. The minimal RL value of samples carbonized at 750 °C reaches −40 dB and the efficient absorption band reaches 9 GHz with the thickness ranges from 2–9 mm. Therefore, this is a facile, effective and economical strategy to prepare yolk–shell structure, which provides a new idea for the preparation of microwave absorption materials.

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“…In principle, multicomponent electromagnetic wave (EMW) absorber can endow materials with adequate heterogeneous interface and improved impedance matching, facilitating EMW response and dissipation to cope with the unwanted electromagnetic pollution problem in current 5G life [ 1 , 2 ]. Maxwell-Wagner-Sillars effect (MWSE), is generated in the heterojunction structures because diverse charge distribution at the boundary between two regions with different dielectric properties [ 3 , 4 ].…”

Section: Introductionmentioning

confidence: 99%

Heterointerface Engineering of β-Chitin/Carbon Nano-Onions/Ni–P Composites with Boosted Maxwell-Wagner-Sillars Effect for Highly Efficient Electromagnetic Wave Response and Thermal Management

Pan

Cai

et al. 2022

Nano-Micro Lett.

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The rational construction of microstructure and composition with enhanced Maxwell-Wagner-Sillars effect (MWSE) is still a challenging direction for reinforcing electromagnetic wave (EMW) absorption performance, and the related EMW attenuation mechanism has rarely been elucidated. Herein, MWSE boosted β-chitin/carbon nano-onions/Ni–P composites is prepared according to the heterointerface engineering strategy via facile layer-by-layer electrostatic assembly and electroless plating techniques. The heterogeneous interface is reinforced from the aspect of porous skeleton, nanomaterials and multilayer construction. The composites exhibit competitive EMW response mechanism between the conductive loss and the polarization/magnetic loss, as describing like the story of “The Hare and the Tortoise”. As a result, the composites not only achieve a minimum reflection loss (RLmin) of − 50.83 dB and an effective bandwidth of 6.8 GHz, but also present remarkable EMW interference shielding effectiveness of 66.66 dB. In addition, diverse functions such as good thermal insulation, infrared shielding and photothermal performance were also achieved in the hybrid composites as a result of intrinsic morphology and chemicophysics properties. Therefore, we believe that the boosted MWSE open up a novel orientation toward developing multifunctional composites with high-efficient EMW response and thermal management.

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3D flower-like Co-based oxide composites with excellent wideband electromagnetic microwave absorption

Cited by 159 publications

References 61 publications

Chemical Surface Adsorption and Trace Detection of Alcohol Gas in Graphene Oxide-Based Acid-Etched SnO₂ Aerogels

Chemical Surface Adsorption and Trace Detection of Alcohol Gas in Graphene Oxide-Based Acid-Etched SnO₂ Aerogels

In Situ Reduced Multi-Core Yolk–Shell Co@C Nanospheres for Broadband Microwave Absorption

Heterointerface Engineering of β-Chitin/Carbon Nano-Onions/Ni–P Composites with Boosted Maxwell-Wagner-Sillars Effect for Highly Efficient Electromagnetic Wave Response and Thermal Management

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3D flower-like Co-based oxide composites with excellent wideband electromagnetic microwave absorption

Cited by 159 publications

References 61 publications

Chemical Surface Adsorption and Trace Detection of Alcohol Gas in Graphene Oxide-Based Acid-Etched SnO2 Aerogels

Chemical Surface Adsorption and Trace Detection of Alcohol Gas in Graphene Oxide-Based Acid-Etched SnO2 Aerogels

In Situ Reduced Multi-Core Yolk–Shell Co@C Nanospheres for Broadband Microwave Absorption

Heterointerface Engineering of β-Chitin/Carbon Nano-Onions/Ni–P Composites with Boosted Maxwell-Wagner-Sillars Effect for Highly Efficient Electromagnetic Wave Response and Thermal Management

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Chemical Surface Adsorption and Trace Detection of Alcohol Gas in Graphene Oxide-Based Acid-Etched SnO₂ Aerogels

Chemical Surface Adsorption and Trace Detection of Alcohol Gas in Graphene Oxide-Based Acid-Etched SnO₂ Aerogels