First principles nuclear magnetic resonance signatures of graphene oxide

Lü, Ning; Huang, Ying; Li, Hai‐Bei; Li, Zhenyu; Yang, Jinlong

doi:10.1063/1.3455715

Cited by 53 publications

(14 citation statements)

References 50 publications

(78 reference statements)

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“…Figure 1 displays the cis-configuration and trans-configuration C 72 O(OH) models and E steric calculated by MM method. The results are consistent with previous theoretical studies 27,29,31,46 that the nearby hydroxyl and epoxy groups tend to locate on the opposite sides of the GO sheet. This tendency can be explained by the structure distortion and tension using the MM theory.…”

Section: A Determination Of Thermodynamically Stable Structuressupporting

confidence: 93%

“…However, as a consequence, the concentration of hydroxyl groups stays at a high level that is not consistent with recent nuclear magnetic resonance signatures of GO. 20,46,50 The experimental nuclear magnetic resonance spectrum does not show a broadened hydroxyl peak, 20,46 so that the chainlike structure might exist but not be a dominant configuration.…”

Section: B Interaction Of Functional Groupsmentioning

confidence: 96%

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A thermodynamic structural model of graphene oxide

Luo

Auchterlonie

Zou

2017

Journal of Applied Physics

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Graphene oxide is an easy-to-make material that has a similar structure with graphene. However, the real structure of graphene oxide is still controversial, and an accurate structural model is crucial for understanding its various properties. In this study, by using molecular mechanics and density functional theory, we introduce a thermodynamically favorable structural model of graphene oxide with chemical composition variable from C 1:5 O to C 2:5 O. We also calculate their theoretical Raman spectra and electronic properties. It has been found that, in the proposed graphene oxide structure, the para-substituted epoxide groups stay in close proximity to the hydroxyl, but on the opposite sides of the carbon sheet. In addition, on the edge of graphene oxide sheet, the carboxyl prefers attachment in the armchair orientation, while the carbonyl prefers the zigzag orientation.

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Section: A Determination Of Thermodynamically Stable Structuressupporting

confidence: 93%

Section: B Interaction Of Functional Groupsmentioning

confidence: 96%

A thermodynamic structural model of graphene oxide

Luo

Auchterlonie

Zou

2017

Journal of Applied Physics

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“…The two main resonances in the Ga 13 C MAS NMR spectrum (Figure 1a) belonged to sp 2 aromatic carbons (about 130 ppm) and alcoholic and epoxide groups (about 70 and 59 ppm, respectively), respectively. Two weak and broad bands were also detectable in the range of 200 ÷ 160 ppm, which can be attributed to small amounts of ketones and edge carboxyls [15]. The main identified resonances in the spectrum of Ga are summarized in Table 1 [16].…”

Section: Resultsmentioning

confidence: 99%

Effect of the Organic Functional Group on the Grafting Ability of Trialkoxysilanes onto Graphene Oxide: A Combined NMR, XRD, and ESR Study

et al. 2019

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The functional properties displayed by graphene oxide (GO)-polymer nanocomposites are strongly affected by the dispersion ability of GO sheets in the polymeric matrix, which can be largely improved by functionalization with organosilanes. The grafting to GO of organosilanes with the general formula RSi(OCH3)3 is generally explained by the condensation reactions of silanols with GO reactive groups. In this study, the influence of the organic group on the RSi(OCH3)3 grafting ability was analyzed in depth, taking into account the interactions of the R end chain group with GO oxidized groups. Model systems composed of commercial graphene oxide reacted with 3-aminopropyltrimethoxysilane (APTMS), 3-mercaptopropyltrimethoxysilane (MPTMS), and 3-methacryloxypropyltrimethoxysilane, (MaPTMS), respectively, were characterized by natural abundance 13C, 15N and 29Si solid state nuclear magnetic resonance (NMR), x-ray diffraction (XRD), and electron spin resonance (ESR). The silane organic tail significantly impacts the grafting, both in terms of the degree of functionalization and direct interaction with GO reactive sites. Both the NMR and XRD proved that this is particularly relevant for APTMS and to a lower extent for MPTMS. Moreover, the epoxy functional groups on the GO sheets appeared to be the preferential anchoring sites for the silane condensation reaction. The characterization approach was applied to the GO samples prepared by the nitric acid etching of graphene and functionalized with the same organosilanes, which were used as a filler in acrylic coatings obtained by cataphoresis, making it possible to correlate the structural properties and the corrosion protection ability of the layers.

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“…While reduction mechanisms of GO and reduced GO have been investigated extensively in recent years62535363738, the stability and structure of GO aged or annealed at moderated temperature (≤ 70°C) have received much less attention to date. Computations based on the density functional theory, in particular, have been used to generate and study model structures of GO39404142, to interpret experimental measurements33344344, and to elucidate reduction mechanisms384245 and the thermodynamic stability of GO4647. In spite of efforts, however, the origin of the chemical and kinetic stability of GO remains elusive to date.…”

mentioning

confidence: 99%

Origin of the Chemical and Kinetic Stability of Graphene Oxide

Zhao

Bongiorno

2013

Sci Rep

172

155

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At moderate temperatures (≤ 70°C), thermal reduction of graphene oxide is inefficient and after its synthesis the material enters in a metastable state. Here, first-principles and statistical calculations are used to investigate both the low-temperature processes leading to decomposition of graphene oxide and the role of ageing on the structure and stability of this material. Our study shows that the key factor underlying the stability of graphene oxide is the tendency of the oxygen functionalities to agglomerate and form highly oxidized domains surrounded by areas of pristine graphene. Within the agglomerates of functional groups, the primary decomposition reactions are hindered by both geometrical and energetic factors. The number of reacting sites is reduced by the occurrence of local order in the oxidized domains, and due to the close packing of the oxygen functionalities, the decomposition reactions become – on average – endothermic by more than 0.6 eV.

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First principles nuclear magnetic resonance signatures of graphene oxide

Cited by 53 publications

References 50 publications

A thermodynamic structural model of graphene oxide

A thermodynamic structural model of graphene oxide

Effect of the Organic Functional Group on the Grafting Ability of Trialkoxysilanes onto Graphene Oxide: A Combined NMR, XRD, and ESR Study

Origin of the Chemical and Kinetic Stability of Graphene Oxide

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