Chemical reduction dependent dielectric properties and dielectric loss mechanism of reduced graphene oxide

Kuang, Boya; Song, Wei‐Li; Ning, Mingqiang; Li, Jingbo; Zhao, Zhiyong; Guo, Deyu; Cao, Mao‐Sheng; Jin, Haibo

doi:10.1016/j.carbon.2017.10.092

Cited by 308 publications

(108 citation statements)

References 55 publications

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“…In addition, the porous rGO not only enhances dielectric loss but also provides resistance loss. The rGO sheets are overlapped to form a capacitorlike conductive network, which causes the motion of hopping electrons, forming oscillatory current and generating increased resistance loss [63][64][65]. Moreover, most of the microwaves enter into the absorber due to the good impedance match, and the unique hierarchically porous structure (the macropores, mesopores, and micropores) of Fe-Co/NC/rGO composite then limits more microwaves to the interior of materials.…”

Section: Electromagnetic Parameters and Microwave Absorption Performancementioning

confidence: 99%

Rational Construction of Hierarchically Porous Fe–Co/N-Doped Carbon/rGO Composites for Broadband Microwave Absorption

Wang

et al. 2019

Nano-Micro Lett.

154

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HIGHLIGHTS• Hierarchically porous Fe-Co/N-doped carbon/rGO (Fe-Co/NC/rGO) composites were successfully prepared. Macropores, mesopores, and micropores coexisted in the composites.• Hierarchically porous Fe-Co/NC/rGO showed effective bandwidth of 9.29 GHz.ABSTRACT Developing lightweight and broadband microwave absorbers for dealing with serious electromagnetic radiation pollution is a great challenge. Here, a novel Fe-Co/N-doped carbon/reduced graphene oxide (Fe-Co/NC/rGO) composite with hierarchically porous structure was designed and synthetized by in situ growth of Fe-doped Cobased metal organic frameworks (Co-MOF) on the sheets of porous cocoon-like rGO followed by calcination. The Fe-Co/NC composites are homogeneously distributed on the sheets of porous rGO. The Fe-Co/NC/rGO composite with multiple components (Fe/Co/NC/rGO) causes magnetic loss, dielectric loss, resistance loss, interfacial polarization, and good impedance matching. The hierarchically porous structure of the Fe-Co/NC/rGO enhances the multiple reflections and scattering of microwaves. Compared with the Co/NC and Fe-Co/NC, the hierarchically porous Fe-Co/NC/rGO composite exhibits much better microwave absorption performances due to the rational composition and porous structural design. Its minimum reflection loss (RL min ) reaches − 43.26 dB at 11.28 GHz with a thickness of 2.5 mm, and the effective absorption frequency (RL ≤ − 10 dB) is up to 9.12 with the same thickness of 2.5 mm. Moreover, the widest effective bandwidth of 9.29 GHz occurs at a thickness of 2.63 mm. This work provides a lightweight and broadband microwave absorbing material while offering a new idea to design excellent microwave absorbers with multicomponent and hierarchically porous structures.

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Section: Electromagnetic Parameters and Microwave Absorption Performancementioning

confidence: 99%

Rational Construction of Hierarchically Porous Fe–Co/N-Doped Carbon/rGO Composites for Broadband Microwave Absorption

Wang

et al. 2019

Nano-Micro Lett.

154

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“…The extensive utilization of electronic devices and wireless equipment in civil and military fields has resulted in serious electromagnetic radiation pollution, which has harmful effects on human body and electronic apparatus [1][2][3]. Therefore, the effective electromagnetic wave (EMW) absorption materials are urgently designed and explored [4].…”

Section: Introductionmentioning

confidence: 99%

In-situ growth of Fe/Fe3O4/C hierarchical architectures with wide-band electromagnetic wave absorption

Meng

Zhang

et al. 2018

Ceramics International

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Carbon materials have aroused extensive interests for their remarkable electrical properties as electromagnetic wave (EMW) absorption. However, the synthesis of the wide-band electromagnetic wave absorbent is an insuperable challenge for attaining effective refection loss and electromagnetic matching. Herein, a facile method for large-scale synthesis of monodispersed Fe/Fe 3 O 4 /C composite microspheres is proposed. The carbon microspheres (1-2 μm in diameter) imbedded with nanosized Fe/Fe 3 O 4 2 particles (10-20 nm) are uniformly produced by polymerization and carbothermic reduction processes. The products exhibit the minimum refection loss-45.5 dB at 9.4 GHz and a broad bandwidth of 4.1 GHz below-10 dB from 7.8 GHz to 11.9 GHz with a thickness of 3.0 mm. The absorption mechanism indicates a unique deviated Debye dipolar relaxation effect in the absorbing bandwidth.

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“…Moreover, based on imaginary permittivity analysis of S2-30wt % sample (Figure 4b), the high conductivity results from the Si(2) silane coupling grafted on the surface of rGO. Next, the dielectric loss of S2 sample is also attributed to the complex interfacial polarization (Si(2)-rGO&PVDF-co-HFP, Si(2)-rGO&Fe 3 O 4 , and Fe 3 O 4 &PVDF-co-HFP) and the lattice defects in graphene structure (Figure 3e), which is beneficial for the EM energy dissipation [16,40]. Meanwhile, the abundant of wrinkles in Si(2)-rGO would provide a channel for improving the multiple-reflection of EMW ( Figure S1b,c, Supplementary Materials).…”

Section: Electromagnetic Propertiesmentioning

confidence: 99%

“…It was suggested that the degree of lattice defects in rGO could be tuned by the increase of VC addition, which could significantly enhance the EMA performance [15]. Meng's group also reported that the nitrogen-doped rGO sheet exhibited the excellent EMA performance in the G band (5.6-8.2 GHz) and X band (8.2-12.4 GHz) due to the existence of the lattice defects in nitrogen-doped rGO [16]. Except for optimizing EM parameters by tuning the degree of defects in rGO, rGO combined with other magnetic loss materials, such as, CoNi [13], CoFe 2 O 4 [17,18], FeCo [18], Fe 3 O 4 [19], and Fe@Fe 3 O 4 [20], is also a meaningful way to control the EMA performance.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Microwave Absorption and Electromagnetic Properties of Si-Modified rGO@Fe3O4/PVDF-co-HFP Composites

Duan

Wang

2020

Materials

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Graphene has been regarded as one of the most promising two-dimensional nanomaterials. Even so, graphene was still faced with several key issues such as impedance mismatching and narrow bandwidth, which have hindered the practical applications of graphene-based nanocomposites in the field of microwave absorption materials. Herein, a series of Si-modified rGO@Fe3O4 composites were investigated and fabricated by a simple method. On one hand, the degree of defects in graphene carbon could be tuned by different silane coupling reagents, which were beneficial to enhancing the dielectric loss. On the other hand, the spherical Fe3O4 nanoparticles provided the magnetic loss resonance, which contributed to controlling the impedance matching. Subsequently, the electromagnetic absorption (EMA) properties of Si-modified rGO@Fe3O4 composites with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) were investigated in this work. As a result, the Si(2)-rGO@Fe3O4/PVDF-co-HFP composite exhibited the excellent EMA performance in the range of 2–18 GHz. The maximum reflection loss (RLmax) reached −32.1 dB at 3.68 GHz at the thickness of 7 mm and the effective absorption frequency bandwidth for reflection loss (RL) below −10 dB was 4.8 GHz at the thickness of 2 mm. Furthermore, the enhanced absorption mechanism revealed that the high-efficiency absorption performance of Si(2)-rGO@Fe3O4/PVDF-co-HFP composite was attributed to the interference absorption (quarter-wave matching model) and the synergistic effects between Si(2)-rGO@Fe3O4 and PVDF-co-HFP. This work provides a potential strategy for the fabrication of the high-performance EMA materials.

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Chemical reduction dependent dielectric properties and dielectric loss mechanism of reduced graphene oxide

Cited by 308 publications

References 55 publications

Rational Construction of Hierarchically Porous Fe–Co/N-Doped Carbon/rGO Composites for Broadband Microwave Absorption

Rational Construction of Hierarchically Porous Fe–Co/N-Doped Carbon/rGO Composites for Broadband Microwave Absorption

In-situ growth of Fe/Fe3O4/C hierarchical architectures with wide-band electromagnetic wave absorption

Enhanced Microwave Absorption and Electromagnetic Properties of Si-Modified rGO@Fe3O4/PVDF-co-HFP Composites

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