Microwave plasma-induced graphene-sheet fibers from waste coffee grounds

Wang, Zhipeng; Ogata, Hironori; Morimoto, Shingo; Fujishige, Masatsugu; Takeuchi, Kenji; Muramatsu, Hiroyuki; Hayashi, T.; Ortiz‐Medina, Josué; Yusop, Mohd Zamri Mohd; Tanemura, Masaki; Terrones, Mauricio; Hashimoto, Yuichi; Endo, Morinobu

doi:10.1039/c5ta03833b

Cited by 22 publications

(19 citation statements)

References 30 publications

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“…Thus, it is important to conduct research on CGs, in order to fully utilize and unlock their potential as the alternative materials for broad applications. CGs have been modified for various usages such as soil remediation, adsorbent materials, and electrochemical energy devices . In most of the cases, CGs need to be carbonized before their further utilization.…”

Section: Raman Information Of Gws Cg Area Pgs and Slg Based On Figmentioning

confidence: 99%

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Graphite Whiskers Derived from Waste Coffee Grounds Treated at High Temperature

et al. 2019

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Graphite whiskers (GWs) are obtained from coffee grounds (CGs) treated at 2500 °C for 1 h in the presence of Ar gas at 1 atm. The majority of the GWs formed inside the CGs shell are rod‐like with a conical tip with diameter and length in the range between 1 to 3 µm and 4 to 10 µm, respectively. At first, the carbon layer might be grown in a turbostratic manner, and then progressively graphitized at higher temperature. The strong G′ peak intensity might be induced by the disclination of graphitized carbon layers.

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Section: Raman Information Of Gws Cg Area Pgs and Slg Based On Figmentioning

confidence: 99%

“…. This is due to the fact that more defects can be expected in our GWs, based on the obvious D and D′ peaks (structural defects or open edges) …”

Section: Raman Information Of Gws Cg Area Pgs and Slg Based On Figmentioning

confidence: 99%

Graphite Whiskers Derived from Waste Coffee Grounds Treated at High Temperature

et al. 2019

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“…4(b) . These results indicate that the NCNs prepared from 2-pyrrolidone may be composed of MLG with turbostratic stacking 37 – 39 . This turbostratic disorder was also apparent from the results of the X-ray diffraction (XRD), which found an interlayer spacing of 0.346 nm (bulk graphite: 0.335 nm) in the (002) diffraction peak (Fig.…”

Section: Resultsmentioning

confidence: 77%

The solution plasma process for heteroatom-carbon nanosheets: the role of precursors

Hyun

Saito

2017

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The solution plasma process (SPP), known as non-equilibrium cold plasma at atmospheric pressure and room temperature, was used to investigate the synthesis of nitrogen-carbon nasnosheets (NCNs). To verify the effect of elementary composition and structure of N-methyl-2-pyrrolidone (NMP), various precursors were used in the SPP to synthesize NCNs via the bottom-up synthesis method for the first time. The NCNs were analyzed by transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Among the various precursors, SPP of 2-pyrrolidone was demonstrated to facilitate the formation of highly ordered NCNs. On the other hand, the SPP with cyclopentanone, cyclohexanone and pyrrole did not lead to the formation of carbon nanosheets. The results of this study would uncover new parameter fields for the growth of heteroatom-carbon nanosheets using this synthesis system. In addition, the study is expected to contribute toward research in improving the large-area growth and quality of two-dimensional nanostructures, such as heteroatom-carbon nanosheets or graphene, for various applications in other synthesis methods.Among various carbon nanomaterials, two-dimensional (2D) carbon allotropes such as carbon nanosheets (CNs), which are composed of few-to multi-layer graphene sheets 1, 2 , have emerged as a promising material for the development of lithium-ion batteries 3 , supercapacitors 4 , organic solar cells 5 , sensitive gas-detection materials 6 , field emission materials 7 , carbon dioxide adsorbents 8 , and fuel cells 9 .The introduction of heteroatoms (e.g., nitrogen or boron) into CNs, which do not exhibit a band gap by themselves, has been important for tailoring their electronic properties and chemical reactivity by opening the band gap and modulating conducting types 10-14 . In particular, nitrogen has attracted much attention as the most common dopant element because it is similar in size to carbon and contains five valence bonds with carbon atoms [15][16][17] . Therefore, it can potentially be used for various applications [18][19][20] .Recently, the solution plasma process (SPP), known as non-equilibrium cold plasma at atmospheric pressure and room temperature 21 , was used to synthesize CNs via the bottom-up synthesis method for the first time 22 . Nitrogen-carbon nasnosheets (NCNs), composed of multi-layer graphene (MLG) with turbostratic stacking, were synthesized by the SPP at a high-repetition frequency with N-methyl-2-pyrrolidone (NMP). The findings demonstrated the advantages of the SPP, such as a short synthesis time, simple experimental apparatus, no impurity issues, and the ability to operate at room temperature, when compared with nanosheets prepared by conventional methods 22,23 . Before the synthesis of NCNs, various organic precursor solutions have been used in the SPP to produce carbon nanomaterials for use in carbon nanomaterial-based electrocatalysts such as fuel cells and lithium-air batteries [24][25][26][27] . Although these syntheses were under the same or simi...

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“…We utilized the microwave plasma irradiation technique to bombard biomass (rice husk and residual coffee grounds), in order to successfully fabricate different graphene-based carbon materials including vertical graphene, graphenated CNTs, which are graphene sheets grown on the walls of CNTs, and graphene-sheet fibers, which possess a large amount of defects and open edges (high I D /I G ratio). [81,82] Current experiments have confirmed that plasma-synthesized vertical graphene displays higher ORR performances than some N-doped CNTs, thus clearly confirming the significant contribution of carbon defects in electrocatalysis.…”

Section: Catalytic Properties Of Defective Nanocarbonsmentioning

confidence: 71%

Defect Engineering and Surface Functionalization of Nanocarbons for Metal‐Free Catalysis

et al. 2019

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With the advent of carbon nanotechnology, which initiated significant research efforts more than two decades ago, novel materials for energy harvesting and storage have emerged at an amazing pace. Nevertheless, some fundamental applications are still dominated by traditional materials, and it is especially evident in the case of catalysis -and environmentalrelated electrochemical reactions, where precious metals such as Pt and Ir have been widely used. Several strategies have been recently explored for achieving competitive and feasible metal-free carbon nanomaterials, among which doping and defect engineering approaches within nanocarbons are recurrent and promising. Here, the most recent efforts regarding the control of doping and defects in carbon nanostructures for catalysis, and in particular for energy-related applications is addressed. Finally, the authors overview alternative proposals that could make a difference when enabling carbon nanomaterials as efficient and emerging catalysts.

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Microwave plasma-induced graphene-sheet fibers from waste coffee grounds

Abstract: Microwave plasma-induced graphene-sheet fibers from waste coffee grounds showed potential applications for electrochemical conversion and storage with excellent performance.

Cited by 22 publications

References 30 publications

Graphite Whiskers Derived from Waste Coffee Grounds Treated at High Temperature

Graphite Whiskers Derived from Waste Coffee Grounds Treated at High Temperature

The solution plasma process for heteroatom-carbon nanosheets: the role of precursors

Defect Engineering and Surface Functionalization of Nanocarbons for Metal‐Free Catalysis

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