Broadband and Lightweight Microwave Absorber Constructed by in Situ Growth of Hierarchical CoFe2O4/Reduced Graphene Oxide Porous Nanocomposites

Yang, Linjun; Chen, Zhuo; Zhang, Yang; Feng, Rui; Chen, Xiao; Xiong, Chuanxi; Dong, Lijie

doi:10.1021/acsami.8b02137

Cited by 224 publications

(95 citation statements)

References 47 publications

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“…Raman spectroscopy data ( Figure 1A) confirmed the structure of rGO reported in the literature for graphene composites reduced by different methods and decorated with magnetic nanoparticles. 29,[31][32][33][34] As expected, an intense D band was found at 1340 cm −1 and a characteristic G band was found at 1585 cm − 1. The D band is associated with structural defects, amorphous carbon, functional groups or edges that can break the symmetry, while the G band is related to the vibrational mode of sp 2 hybridized carbon atoms.…”

Section: Characterization Of Rgo-fe 3 O 4 Nanocompositesupporting

confidence: 81%

Efficacy and Molecular Effects of a Reduced Graphene Oxide/Fe3O4 Nanocomposite in Photothermal Therapy Against Cancer

Barrera¹,

Groot²,

Vargas³

et al. 2020

IJN

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Purpose: Expanded research on the biomedical applications of graphene has shown promising results, although interactions between cells and graphene are still unclear. The current study aims to dissect the cellular and molecular effects of graphene nanocomposite in photothermal therapy against cancer, and to evaluate its efficacy. Methods: In this study, a reduced graphene oxide and iron oxide (rGO-Fe 3 O 4) nanocomposite was obtained by chemical synthesis. The nanocomposite was fully characterized by Raman spectroscopy, TEM, VSM and thermal profiling. Cell-nanocomposite interaction was evaluated by confocal microscopy and viability assays on cancer cell line HeLa. The efficacy of the thermal therapy and changes in gene expression of Bcl-2 and Hsp70 was assessed. Results: The resulting rGO-Fe 3 O 4 nanocomposite exhibited superparamagnetic properties and the capacity to increase the surrounding temperature by 18-20°C with respect to the initial temperature. The studies of cell-nanocomposite interaction showed that rGO-Fe 3 O 4 attaches to cell membrane but there is a range of concentration at which the nanomaterial preserves cell viability. Photothermal therapy reduced cell viability to 32.6% and 23.7% with 50 and 100 µg/mL of nanomaterial, respectively. The effect of treatment on the molecular mechanism of cell death demonstrated an overexpression of anti-apoptotic proteins Hsp70 and Bcl-2 as an initial response to the therapy and depending on the aggressiveness of the treatment. Conclusion: The results of this study contribute to understanding the interactions between cell and graphene and support its application in photothermal therapy against cancer due to its promising results.

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Section: Characterization Of Rgo-fe 3 O 4 Nanocompositesupporting

confidence: 81%

Efficacy and Molecular Effects of a Reduced Graphene Oxide/Fe3O4 Nanocomposite in Photothermal Therapy Against Cancer

Barrera¹,

Groot²,

Vargas³

et al. 2020

IJN

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“…designed carbon‐encapsulated Fe nanoparticles embedded in organic polypyrrole polymer as a high‐performance microwave absorber, whose reflection loss exceeding −10 dB is obtained in the 9.6–14.1 GHz for a given thickness of 2.5 mm . A broadband and lightweight microwave absorber constructed by in situ growth of hierarchical CoFe 2 O 4 /rGO porous nanocomposites was synthesized by Dong and coworkers, exhibited superior microwave absorption performance with an ultra‐broad bandwidth reaching 5.8 GHz (8.3–14.1 GHz) with a thin thickness of 2.8 mm and a strong reflection loss of −57.7 dB …”

Section: Introductionmentioning

confidence: 99%

Novel, promising, and broadband microwave‐absorbing nanocomposite based on the graphite‐like carbon nitride/CuS

Peymanfar

Karimi²,

Fallahi³

2019

J of Applied Polymer Sci

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In this study, a broadband, intense, novel, and promising microwave-absorbing nanocomposite was prepared using graphite-like carbon nitride (g-C 3 N 4 )/CuS suspended in poly(methyl methacrylate) (PMMA) medium. The g-C 3 N 4 nanosheets were synthesized by heating the urea as well as the CuS nanoparticles, and g-C 3 N 4 /CuS nanocomposites were prepared using a solvothermal method and then were separately molded by a PMMA solution to investigate their microwave-absorbing characteristics. The Fourier transform infrared and X-ray powder diffraction were used to characterize the g-C 3 N 4 , CuS, and CuS/g-C 3 N 4 nanostructures, which confirmed that the pure structure of the nanomaterials has been synthesized. The optical properties of the nanostructures were also investigated by diffuse reflection spectroscopy analysis. Accordingly, the Kubelka-Munk theory suggested significant narrow band gap for g-C 3 N 4 /CuS nanocomposite (0.27 eV), facilitating electron jumping and conductive loss. The morphology of the structures was examined using field emission scanning electron microscopy micrographs, illustrating that the uniform hexagonal structures of the CuS nanoplates have been formed and the CuS two-dimensional structures were uniformly distributed on the g-C 3 N 4 nanosheets. Finally, the microwave-absorbing properties of the CuS, g-C 3 N 4 , and g-C 3 N 4 /CuS were investigated by PMMA as a host. The microwaveabsorbing properties were evaluated using a vector network analyzer. The results illustrated that the maximum reflection loss of the g-C 3 N 4 /PMMA nanocomposite was −71.05 dB at 14.90 GHz with a thickness of 2.00 mm, demonstrating a 1.70 GHz bandwidth >30 dB, as well as g-C 3 N 4 /CuS/PMMA nanocomposite absorbed 7.30 GHz bandwidth of more than 10 dB with a thickness of 1.80 mm along the x-and ku-band frequency. The obtained results introduced the PMMA as a capable microwave-absorbing substrate. Besides, the g-C 3 N 4 /CuS/PMMA nanocomposite demonstrated metamaterial property and abundant attenuation constant.

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“…According to the microwave absorption mechanism, when absorbers have magnetic loss, dielectric loss, and impedance match, more microwaves can enter the interior of the materials and be converted into other forms of energy and dissipated [8,9]. In past decades, many efforts were devoted to researching composites for enhancing microwave absorption, such as (Fe, Ni, Co)/C [10][11][12], (Fe, Ni, Co)/rGO [13][14][15], MFe 2 O 4 /rGO (M = Fe, Ni, Co) [16][17][18][19], MFe 2 O 4 / CNTs [20][21][22], and NiO/SiO 2 /Fe 3 O 4 /rGO [23,24]. However, these materials have the shortcoming of narrow absorption bands, which seriously hinders their practical applications.…”

mentioning

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.

151

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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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Broadband and Lightweight Microwave Absorber Constructed by in Situ Growth of Hierarchical CoFe₂O₄/Reduced Graphene Oxide Porous Nanocomposites

Cited by 224 publications

References 47 publications

<p>Efficacy and Molecular Effects of a Reduced Graphene Oxide/Fe<sub>3</sub>O<sub>4</sub> Nanocomposite in Photothermal Therapy Against Cancer</p>

<p>Efficacy and Molecular Effects of a Reduced Graphene Oxide/Fe<sub>3</sub>O<sub>4</sub> Nanocomposite in Photothermal Therapy Against Cancer</p>

Novel, promising, and broadband microwave‐absorbing nanocomposite based on the graphite‐like carbon nitride/CuS

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

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