Raman scattering in a new carbon material

Voronov, O. A.; Street, Kenneth W.

doi:10.1016/j.diamond.2009.10.018

Cited by 15 publications

(5 citation statements)

References 10 publications

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“…5,21,22 In order to quantitatively evaluate the functionalization degree, it is important to identify the disorder arising from covalent functionalization, related to the transformation of sp 2 aromatic carbon into sp 3 carbon, and distinguishing it from the other structural effects and deviations to the perfect graphite structure. These include, non-uniform planar-layer stacking shapes, such as the curvature in carbon nanotubes or nanofibers, 23 the reduction of the graphitic crystal size going from bulk to nanoscale materials (the presence of edge structures) 24,25 or the presence of amorphous carbon. 26,27 In the present work, we report a comparative Raman study of covalently functionalized MWCNTs through a reaction with anilines, in the presence and absence of isopentyl nitrite 28 and through oxidation by liquid and gas phase procedures 29 (Fig.…”

Section: Introductionmentioning

confidence: 99%

Progress in the Raman spectra analysis of covalently functionalized multiwalled carbon nanotubes: unraveling disorder in graphitic materials

Rebelo

Guedes

Szefczyk

et al. 2016

Phys. Chem. Chem. Phys.

241

121

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Raman spectroscopy is highly sensitive to the morphology and electronic structures of graphitic materials, but a convenient interpretation model has been lacking for multiwalled carbon nanotubes (MWCNTs), in particular for the discrimination of spectral changes induced by covalent functionalization. The present work describes a systematic investigation of the Raman analysis of covalently functionalized MWCNTs by diazonium chemistry and oxidation methodologies, with typically different mechanisms and reaction sites. A multi-peak deconvolution system and spectral band assignment were proposed based on the chemical and structural modifications identified by X-ray photoelectron spectroscopy, thermogravimetry, X-ray diffraction, specific surface areas and the comparative analysis of the first and second order regions of the Raman spectra. Diazonium functionalization takes place mainly in the π-system of the external sidewall, while oxidation occurs on defects and leads to structure burning. This allowed us to distinguish between spectral features related to aromaticity disruptions within the sidewalls and spectral features related to changes within the inner tubes. The model was validated extending the studies to the functionalization of MWCNTs by the Bingel reaction.

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Section: Introductionmentioning

confidence: 99%

Progress in the Raman spectra analysis of covalently functionalized multiwalled carbon nanotubes: unraveling disorder in graphitic materials

Rebelo

Guedes

Szefczyk

et al. 2016

Phys. Chem. Chem. Phys.

241

121

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“…Raman spectra (Figure b) revealed two remarkable peaks at 1350 and 1591 cm –1 , which corresponded to sp 3 hybridized amorphous carbon and sp 2 hybridized graphitic carbon. The ratio of the peak area ( I D / I G ) demonstrated the defective structure of carbon materials. ,, As shown in Figure b, the ratios of I D / I G for LPAC, LKAC, and LSAC were 2.10, 2.54, and 2.20, correspondingly, which proved that the samples possessed great quantities of defects with low degree of graphitization. LKAC with a higher ratio of I D / I G indicates its lower degree of graphitization, which fitted the results of XRD.…”

Section: Resultsmentioning

confidence: 88%

From Black Liquor to Green Energy Resource: Positive Electrode Materials for Li–O₂ Battery with High Capacity and Long Cycle Life

Zhang

Yao

Zhao

et al. 2020

ACS Appl. Mater. Interfaces

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Black liquor has caused a tremendous degree of pollution and waste. Exploring the utilization of lignin, which is the major component of black liquor, has become a key factor in dealing with the problem. In this study, lignin derived from black liquor was used as a raw material to prepare carbon materials through different activation methods including KOH, H3PO4, and steam activation. The structure and properties of obtained samples were characterized as well as electrochemical performance when applied on a lithium–oxygen battery. Results of N2 adsorption/desorption showed that all obtained samples possessed high surface area of over 1000 m2/g. XRD, Raman, and XPS also indicated that obtained samples possessed a large defect area and many functional groups. Electrochemical measurements illustrated that all obtained samples exhibited a high discharge capacity over 2.8 mAh/cm2 at 0.02 mA/cm2, while LKAC exhibited the highest discharge capacity of 7.2 mAh/cm2. Cycling tests of all obtained samples indicated a long cycle life of at least 300 cycles. LSAC maintained a 100% retention rate of capacity and stable terminal voltage even after 800th cycle, and its cycling performance was investigated further by XRD and EIS. This study demonstrated excellent performance for lignin-based carbon materials, and provided alternative materials for positive electrode of lithium–oxygen battery.

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“…2 [20], which is believed to be caused by higher energy input with the charging voltage of 40 kV. While the ID/IG of all recovered samples Raman spectroscopy is very informative and sensitive for studying carbon materials [36]. It provides a quick and facile identification of carbon materials [21,23,37,38], which is a significant method to identify graphene.…”

Section: Resultsmentioning

confidence: 99%

Preparation of Few-Layer Graphene by Pulsed Discharge in Graphite Micro-Flake Suspension

et al. 2019

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Few-layer graphene nanosheets were produced by pulsed discharge in graphite micro-flake suspension at room temperature. In this study, the discharging current and voltage data were recorded for the analysis of the pulsed discharge processes. The as-prepared samples were recovered and characterized by various techniques, such as TEM, SEM, Raman, XRD, XPS, FT-IR, etc. The presence of few-layer graphene (3–9 L) in micrometer scale was confirmed. In addition, it is investigated that the size of recovered graphene nanosheets are influenced by the initial size of utilized graphite micro-flake powder. Based on the process of pulsed discharge and our experimental results, the formation mechanism of few-layer graphene was discussed. The influence of charging voltage on as-prepared samples is also investigated.

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Raman scattering in a new carbon material

Cited by 15 publications

References 10 publications

Progress in the Raman spectra analysis of covalently functionalized multiwalled carbon nanotubes: unraveling disorder in graphitic materials

Progress in the Raman spectra analysis of covalently functionalized multiwalled carbon nanotubes: unraveling disorder in graphitic materials

From Black Liquor to Green Energy Resource: Positive Electrode Materials for Li–O₂ Battery with High Capacity and Long Cycle Life

Preparation of Few-Layer Graphene by Pulsed Discharge in Graphite Micro-Flake Suspension

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Raman scattering in a new carbon material

Cited by 15 publications

References 10 publications

Progress in the Raman spectra analysis of covalently functionalized multiwalled carbon nanotubes: unraveling disorder in graphitic materials

Progress in the Raman spectra analysis of covalently functionalized multiwalled carbon nanotubes: unraveling disorder in graphitic materials

From Black Liquor to Green Energy Resource: Positive Electrode Materials for Li–O2 Battery with High Capacity and Long Cycle Life

Preparation of Few-Layer Graphene by Pulsed Discharge in Graphite Micro-Flake Suspension

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Product

Resources

About

From Black Liquor to Green Energy Resource: Positive Electrode Materials for Li–O₂ Battery with High Capacity and Long Cycle Life