Synthesis of lightweight N-doped graphene foams with open reticular structure for high-efficiency electromagnetic wave absorption

Liu, Panbo; Zhang, Yiqing; Yan, Jing; Huang, Ying; Xia, Long; Guang, Zhaoxu

doi:10.1016/j.cej.2019.02.193

Cited by 666 publications

(235 citation statements)

References 62 publications

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“…This result, forming porous structure of crystalline Fe/MnO@C-amorphous carbon composition, is coordinated with that of TEM and XRD. The large specific surface area and porous structure benefit the improvement of impedance matching behavior and microwave attenuation [38][39][40][41][42][43][44]. The surface areas and pores is conducive to impedance of fillers and boosts microwave penetrating into materials, which is a competent way to broaden absorption bandwidth.…”

Section: Structure and Phase Characterizationmentioning

confidence: 99%

Microwave Absorption of Crystalline Fe/MnO@C Nanocapsules Embedded in Amorphous Carbon

2020

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HIGHLIGHTS• The crystalline Fe/MnO@C core-shell nanocapsules embedded in porous amorphous carbon matrix (FMCA) was prepared by a novel confinement strategy of modified arc-discharge method.• The heterogeneous crystalline-amorphous nanocrystals disperse evenly and exhibit improvement of static magnetization and excellent electromagnetic absorption properties. • The adding MnO 2 confines degree of graphitization and contributes to form amorphous carbon. Dielectric loss and microwave absorption are achieved adjustable. ABSTRACT Crystalline Fe/MnO@C core-shell nanocapsules inlaid in porous amorphous carbon matrix (FMCA) was synthesized successfully with a novel confinement strategy. The heterogeneous Fe/ MnO nanocrystals are with approximate single-domain size which gives rise to natural resonance in 2-18 GHz. The addition of MnO 2 confines degree of graphitization catalyzed by iron and contributes to the formation of amorphous carbon. The heterogeneous materials composed of crystalline-amorphous structures disperse evenly and its density is significantly reduced on account of porous properties. Meanwhile, adjustable dielectric loss is achieved by interrupting Fe core aggregation and stacking graphene conductive network. The dielectric loss synergistically with magnetic loss endows the FMCA enhanced absorption. The optimal reflection loss (RL) is up to − 45 dB, and the effective bandwidth (RL < − 10 dB) is 5.0 GHz with 2.0 mm thickness. The proposed confinement strategy not only lays the foundation for designing high-performance microwave absorber, but also offers a general duty synthesis method for heterogeneous crystalline-amorphous composites with tunable composition in other fields.

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Section: Structure and Phase Characterizationmentioning

confidence: 99%

Microwave Absorption of Crystalline Fe/MnO@C Nanocapsules Embedded in Amorphous Carbon

2020

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“…Firstly, Cu foil was cleaned with acetone and isopropyl alcohol [60][61][62] Then, Cu film was annealed at temperatures of 900 to 1000°C to raise grain size under an atmosphere of Ar/H 2 . Firstly, Cu foil was cleaned with acetone and isopropyl alcohol [60][61][62] Then, Cu film was annealed at temperatures of 900 to 1000°C to raise grain size under an atmosphere of Ar/H 2 .…”

Section: The Few-layer Graphene Synthesismentioning

confidence: 99%

“…Electrochemical measurements of these electrodes were performed in a three-electrode system with a CHI 660E potentiostat. [60][61][62] The graphitic carbon peaks of N-doped G/ITO showed negative shift in according to graphene on Cu foil, indicating nitrogen penetration into lattice structure of graphitic carbon. On the other hand, Ag/AgCl electrode was employed as reference electrode.…”

Section: Electrochemical Measurements Of Modified Graphene/ito Elecmentioning

confidence: 99%

“…The few-layer graphene was coated on Cu foil with the CVD method. Firstly, Cu foil was cleaned with acetone and isopropyl alcohol [60][61][62] Then, Cu film was annealed at temperatures of 900 to 1000°C to raise grain size under an atmosphere of Ar/H 2 . After Cu foil was annealed, hydrogen gas was fed into the reactor medium.…”

Section: The Few-layer Graphene Synthesismentioning

confidence: 99%

“…The diffraction peaks at approximately 21, 43, and 50°were due to the C (0 0 2), Cu (1 1 1), and Cu (2 0 0) facets with their spacing between planes (d) that were 4.13, 2.09, and 1.81 Å, respectively ( Figures 1A-1c). [60][61][62] The graphitic carbon peaks of N-doped G/ITO showed negative shift in according to graphene on Cu foil, indicating nitrogen penetration into lattice structure of graphitic carbon. 63 For all electrodes, diffraction peaks were obtained at similar 2⊖ values, but changes in the intensity of these peaks were detected, and these changes also support the introduction of nitrogen into the graphene layers.…”

Section: Electrochemical Measurements Of Modified Graphene/ito Elecmentioning

confidence: 99%

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Synthesis of in situ N‐, S‐, and B‐doped few‐layer graphene by chemical vapor deposition technique and their superior glucose electrooxidation activity

2019

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Summary At present, N‐, S‐, and B‐doped grapheme‐modified indium tin oxide (ITO) electrodes are produced and doping method effect on the glucose electrooxidation is investigated. Firstly, few‐layer graphene is produced by chemical vapor deposition (CVD) method. Then, N, S, and B doping is carried out after graphene produced by CVD to prepare N‐doped, B‐doped, and S‐doped few‐layer graphene. N, S, and B doping is carried out by two different ways as (a) doping after synthesis of few‐layer graphene and (b) in situ doping during few‐layer graphene production. These materials are characterized by X‐ray diffraction, scanning electron microscopy‐energy (SEM), Raman spectroscopy, and X‐ray photoelectron spectroscopy (XPS). One could note that graphene and nitrogen networks are clearly visible from SEM images. Raman spectra show that B, N, and S are doped on few‐layer graphene/ITO successfully. XPS results of graphene, N‐doped graphene, and in situ N‐doped graphene reveal that graphene and nitrogen atoms used in the preparation of the electrodes obtain mainly in their elemental state. Then, these N‐, S‐, B‐doped and in situ N‐, S‐, B‐doped few‐layer graphene materials are coated onto indium tin oxide (ITO) to obtain N‐, S‐, B‐doped and in situ N‐, S‐, B‐doped ITO electrodes for glucose (C6H12O6) electrooxidation. C6H12O6 electrooxidation measurements are investigated with cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy measurements. As a result, in situ N‐doped few‐layer graphene/ITO electrode displays the best C6H12O6 electrooxidation activity with 9.12 mA.cm−2 current density compared with other N‐, S‐, B‐doped graphene and in situ doped S and B grapheme‐modified ITO electrodes. Furthermore, this current density value for in situ N‐doped few‐layer graphene/ITO is highly above the values reported in the literature. In situ N‐doped few‐layer graphene/ITO electrode is a promising electrode for C6H12O6 electrooxidation because it exhibits the best electrocatalytic activity, stability, and resistance compared with other electrodes.

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Integrated Foam‐Type Electromagnetic Wave Absorption Materials

Chang

2024

Electromagnetic Wave Absorbing Materials

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Synthesis of lightweight N-doped graphene foams with open reticular structure for high-efficiency electromagnetic wave absorption

Cited by 666 publications

References 62 publications

Microwave Absorption of Crystalline Fe/MnO@C Nanocapsules Embedded in Amorphous Carbon

Microwave Absorption of Crystalline Fe/MnO@C Nanocapsules Embedded in Amorphous Carbon

Synthesis of in situ N‐, S‐, and B‐doped few‐layer graphene by chemical vapor deposition technique and their superior glucose electrooxidation activity

Integrated Foam‐Type Electromagnetic Wave Absorption Materials

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