One-step electrochemical synthesis of nitrogen and sulfur co-doped, high-quality graphene oxide

Parvez, Khaled; Rincón, Rosalba A.; Weber, Nils-Eike; Kitty, C.; Venkataraman, Shyam S.

doi:10.1039/c6cc01250g

Cited by 67 publications

(52 citation statements)

References 29 publications

(32 reference statements)

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“…It has been shown that nearly pristine graphene with a C/O of 25.3 and mobility of 405 cm 2 ·V −1 s −1 could be synthesized within seconds by EC exfoliation of graphite foil 28 . Inspired by these successes, researchers also tried to synthesize GO by EC oxidation of various graphitic materials such as pencile core 29 , graphite rode 30 and graphite flakes 31 , 32 . Unfortunately, the accompanied water/solvent electrolysis process aggravates the expansion and delamination of graphitic materials, which lead to ineffective current supply or broken circuit before the desired EC oxidation process can be achieved 27 , 28 .…”

Section: Introductionmentioning

confidence: 99%

Green synthesis of graphene oxide by seconds timescale water electrolytic oxidation

et al. 2018

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Graphene oxide is highly desired for printing electronics, catalysis, energy storage, separation membranes, biomedicine, and composites. However, the present synthesis methods depend on the reactions of graphite with mixed strong oxidants, which suffer from explosion risk, serious environmental pollution, and long-reaction time up to hundreds of hours. Here, we report a scalable, safe and green method to synthesize graphene oxide with a high yield based on water electrolytic oxidation of graphite. The graphite lattice is fully oxidized within a few seconds in our electrochemical oxidation reaction, and the graphene oxide obtained is similar to those achieved by the present methods. We also discuss the synthesis mechanism and demonstrate continuous and controlled synthesis of graphene oxide and its use for transparent conductive films, strong papers, and ultra-light elastic aerogels.

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Section: Introductionmentioning

confidence: 99%

Green synthesis of graphene oxide by seconds timescale water electrolytic oxidation

et al. 2018

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“…A reduced graphene with a very high C/O ratio (25.3) and high electron mobility has been synthesized within seconds by electrochemical exfoliation of graphite foil [23]. Analogously, GO has been produced by electrochemical oxidation of several graphitic materials in a variety of geometries such as pencil cores and graphite powders, foils, rods, or plates [24][25][26][27]. The reported approaches have emerged as promising and versatile alternatives to the chemical methods.…”

Section: Introductionmentioning

confidence: 99%

Tailorable Synthesis of Highly Oxidized Graphene Oxides via an Environmentally-Friendly Electrochemical Process

et al. 2020

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Graphene oxide (GO) is an attractive alternative to graphene for many applications due to its captivating optical, chemical, and electrical characteristics. In this work, GO powders with a different amount of surface groups were synthesized from graphite via an electrochemical two-stage process. Many synthesis conditions were tried to maximize the oxidation level, and comprehensive characterization of the resulting samples was carried out via elemental analysis, microscopies (TEM, SEM, AFM), X-ray diffraction, FT-IR and Raman spectroscopies as well as electrical resistance measurements. SEM and TEM images corroborate that the electrochemical process used herein preserves the integrity of the graphene flakes, enabling to obtain large, uniform and well exfoliated GO sheets. The GOs display a wide range of C/O ratios, determined by the voltage and time of each stage as well as the electrolyte concentration, and an unprecedented minimum C/O value was obtained for the optimal conditions. FT-IR evidences strong intermolecular interactions between neighbouring oxygenated groups. The intensity ratio of D/G bands in the Raman spectra is high for samples prepared using concentrated H2SO4 as an electrolyte, indicative of many defects. Furthermore, these GOs exhibit smaller interlayer spacing than that expected according to their oxygen content, which suggests predominant oxidation on the flake edges. Results point out that the electrical resistance is conditioned mostly by the interlayer distance and not simply by the C/O ratio. The tuning of the oxidation level is useful for the design of GOs with tailorable structural, electrical, optical, mechanical, and thermal properties.

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“…In general, the presence of electronic conductivity of films in a dry atmosphere can be a qualitative criterion for a small degree of functionalization of FLGS surface. However, in our case, the oxygen content in FLGS is sufficiently high and electronic conductivity should be explained by the fact that functional groups are mainly concentrated at the edges of graphene planes, and basal planes themselves do not undergo significant changes compared to the original graphite [20].…”

Section: Resultsmentioning

confidence: 57%

“…Data obtained for the edge of the film formed by c-FLGS is presented in Figure 2 [18,19] suggests that oxygen-containing functional groups on the surface of FLGS are represented by epoxy (286.7 eV), hydroxy (285.3 eV), and carboxyl (288.7 eV) groups ( Table 1). The deconvolution of the S2p peak (Figures 3(c) and 3(f)) reveals the presence of C-SO 3 group at 169.6 eV for both samples and C-SO 2 at 168.4 eV for c-FLGS [20]. Figure 4 shows current-time curves of FLGS films, obtained by plasma-assisted electrochemical exfoliation of graphite using cathodic (curve 1) and anodic plasma (curve 2).…”

Section: Resultsmentioning

confidence: 99%

Electrical Conductivity of Films Formed by Few-Layer Graphene Structures Obtained by Plasma-Assisted Electrochemical Exfoliation of Graphite

Vasiliev

Manzhos

Krivenko

2019

International Journal of Electrochemistry

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Current-voltage characteristics of few-layer graphene structures (FLGS) obtained by plasma-assisted electrochemical exfoliation of graphite in Na2SO4 solution were measured. FLGS are shown to possess electronic conductivity, which indicates the predominant functionalization of the edges of graphene planes and the preservation of the structure of basal planes in obtained nanostructures as in the source graphite. The effect of humidity on the conductivity of FLGS films was studied. The resistance of films was found to increase with an increase in the relative humidity of the environment due to the shielding of FLGS flakes by a film of water. The effect of different solvents on the current-voltage characteristics of FLGS was analyzed. The conductivity of films significantly decreased in vapors of polar protic solvents, while there was a minor effect of nonpolar aprotic solvents on the conductivity of FLGS films.

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One-step electrochemical synthesis of nitrogen and sulfur co-doped, high-quality graphene oxide

Cited by 67 publications

References 29 publications

Green synthesis of graphene oxide by seconds timescale water electrolytic oxidation

Green synthesis of graphene oxide by seconds timescale water electrolytic oxidation

Tailorable Synthesis of Highly Oxidized Graphene Oxides via an Environmentally-Friendly Electrochemical Process

Electrical Conductivity of Films Formed by Few-Layer Graphene Structures Obtained by Plasma-Assisted Electrochemical Exfoliation of Graphite

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