Liquid Phase Production of Graphene by Exfoliation of Graphite in Surfactant/Water Solutions

Lotya, Mustafa; Hernández, Yenny; King, Paul J.; Smith, Ronan J.; Nicolosi, Valeria; Karlsson, Lisa; Blighe, Fiona M.; De, Sourya Joyee; Wang, Zhiming; McGovern, I.T.; Duesberg, Georg S.; Coleman, Jonathan N.

doi:10.1021/ja807449u

Cited by 2,110 publications

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“…On its own, water is a poor solvent for the exfoliation of graphite, whereas surfactant-water solutions can exfoliate graphite to produce stable aqueous dispersions of graphene 28 . Graphene oxide (GO) has previously been suggested as a 2D-surfactant to prepare stable dispersions of graphite and carbon nanotubes (CNTs) in water 29,30 .…”

Section: Swelling-controlled Graphene Oxide-graphene (Go-gr)membranesmentioning

confidence: 99%

“…The effective pore-size of 9 Å in these swollen membranes (excluding the space occupied by carbon atoms) is larger than a typical size of hydrated ions and restricts possible uses of GO for size-exclusion based ion sieving 19 . A number of strategies have been tried to inhibit the swelling effect, including partial reduction of GO 25 , ultraviolet reduction of GO-titania hybrid membranes 26 , and covalent crosslinking [27][28][29] . In this report, we investigate ion permeation through GO laminates with d controlled from ≈ 9.8 to ≈ 6.4 Å, which is achieved by physical confinement (Fig.…”

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Tunable sieving of ions using graphene oxide membranes

et al. 2017

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Graphene oxide membranes show exceptional molecular permeation properties, with a promise for many applications. However, their use in ion sieving and desalination technologies is limited by a permeation cutoff of 9 Å, which is larger than hydrated ion diameters for common salts. The cutoff is determined by the interlayer spacing d 13.5 Å, typical for graphene oxide laminates that swell in water. Achieving smaller d for the laminates immersed in water has proved to be a challenge. Here we describe how to control d by physical confinement and achieve accurate and tuneable ion sieving. Membranes with d from  9.8 Å to 6.4 Å are demonstrated, providing the sieve size smaller than typical ions' hydrated diameters. In this regime, ion permeation is found to be thermally activated with energy barriers of 10-100 kJ/mol depending on d. Importantly, permeation rates decrease exponentially with decreasing the sieve size but water transport is weakly affected (by a factor of <2). The latter is attributed to a low barrier for water molecules entry and large slip lengths inside graphene capillaries. Building on these findings, we demonstrate a simple scalable method to obtain graphene-based membranes with limited swelling, which exhibit 97% rejection for NaCl.Selectively permeable membranes with sub-nm pores attract strong interest due to analogies with biological membranes and potential applications in water filtration, molecular separation and desalination [1][2][3][4][5][6][7][8] . Nanopores with sizes comparable to, or smaller than, the diameter D of hydrated ions are predicted to show enhanced ion selectivity 7,9-12 because of dehydration required to pass through such atomic-scale sieves. Despite extensive research on ion dehydration effects 3,7,9-13 , experimental investigation of the ion sieving controlled by dehydration has been limited because of difficulties in fabricating uniform membranes with well-defined sub-nm pores. The realisation of membranes with dehydration-assisted selectivity would be a significant step forward. So far, research into novel membranes has mostly focused on improving the water flux rather than ion selectivity. On the other hand, modelling of practically relevant filtration processes shows that an increase in water permeation rates above the rates currently achieved (2-3 L/m 2 ×h×bar) would not contribute greatly to the overall efficiency of desalination 8,14,15 . Alternative approaches based on higher water-ion selectivity may open new possibilities for improving filtration technologies, as the performance of state-of-the-art membranes is currently limited by the solution-diffusion mechanism, in which water molecules dissolve in the membrane material and then diffuses across the membrane 8 . Recently, carbon nanomaterials including carbon nanotubes (CNT)

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Section: Swelling-controlled Graphene Oxide-graphene (Go-gr)membranesmentioning

confidence: 99%

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confidence: 99%

Tunable sieving of ions using graphene oxide membranes

et al. 2017

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“…7,8 Probably the simplest route to liquid exfoliation of layered compounds is sonication assisted exfoliation in solvents [23][24][25][26][27][28][29] or aqueous surfactant solutions. 19,[30][31][32] Here, sonication results in the exfoliation of the layered crystal into single and multilayer nanosheets which are then stabilised by interaction with the solvent or a surfactant. This method has the advantage of extreme simplicity coupled with the fact that it results in small but highquality exfoliated nanosheets which can then be fabricated into films or composite materials.…”

Section: Toc Figmentioning

confidence: 99%

Solvent Exfoliation of Transition Metal Dichalcogenides: Dispersibility of Exfoliated Nanosheets Varies Only Weakly between Compounds

et al. 2012

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Abstract:We have studied the dispersion and exfoliation of four inorganic layered compounds, WS 2 , We found that the dispersed concentration of each material falls exponentially with  as predicted by solution thermodynamics. This work shows that solution thermodynamics and specifically solubility parameter analysis can be used as a framework to understand the dispersion of 2-dimensional materials. Finally, we note that in good solvents such as 2 cyclohexylpyrrolidone, the dispersions are temporally stable with >90% of material remaining dispersed after 100 hours. ToC figOver the last decade, 2-dimensional nanomaterials have become one of the most studied subfields of nanoscience. These developments have been spearheaded by research into graphene, a material that is unique due to its combination of thermal, electronic, optical and mechanical properties. 1-5 However, over the last few years, it has become clear that a range of other inorganic layered compounds can be mechanically exfoliated in small quantities to give 2-dimensional nanosheets with interesting properties. 6-10 For example, exfoliated hexagonal boron nitride has been used as a dielectric support in graphene-based transistors 11 while MoS 2 has been fabricated into sensors 10, 12 , transistors 13-15 and integrated circuits. 16 The availability of a wide range of 2-dimensional materials is important as it allows access to a broad palette of physical and chemical properties. A good example is provided by the family of transition metal dichalcogenides (TMDs). These materials have the chemical composition MX 2 where M is a transition metal (commonly, but not limited to Ti, Nb, Ta, Mo, W) and X is a chalcogen (i.e. S, Se, Te). As in graphite, these atoms are covalently bonded into nanosheets which stack into 3-dimensional crystals by van der Waals interactions. These materials are of particular interest because, depending on the combination of metal and chalcogen, the material can be semiconducting or metallic. 17 In addition, the bandgap can vary from a few hundred meV to a few eV, 17 suggesting these materials have potential as versatile electronic device materials.Furthermore, these materials have interesting electrochemical properties which make them suitable for applications such as battery electrodes. 18,19 As with graphene, many applications will require relatively large quantities of material suggesting that a solution processing route is required. 20 A number of possibilities exist. For example, it has been known for many years that materials such as MoS 2 can be exfoliated by 3 lithium intercalation. 21 However, such a route tends to result in structural deformations in some TMDs leading to considerably altered electronic properties. 22 Alternatively, TMDs can be synthesised in the liquid phase. 7,8 Probably the simplest route to liquid exfoliation of layered compounds is sonication assisted exfoliation in solvents [23][24][25][26][27][28][29] or aqueous surfactant solutions. 19,[30][31][32] Here, sonication results in the exfoliation of the ...

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“…Pristine graphene was originally obtained by mechanical exfoliation of graphite in 2004,1 versatile methods have since been developed toward synthesis of graphene, such as oxidation of graphite,6 liquid‐phase exfoliation,7, 8 chemical vapor deposition (CVD)9, 10, 11, 12 and thermal decomposition of SiC 13, 14. However, liquid‐phase exfoliated graphene usually suffers from structure defects and uncontrollable size, shape, layer numbers.…”

Section: Introductionmentioning

confidence: 99%

Controllable Synthesis of Graphene by Plasma‐Enhanced Chemical Vapor Deposition and Its Related Applications

et al. 2016

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Graphene and its derivatives hold a great promise for widespread applications such as field‐effect transistors, photovoltaic devices, supercapacitors, and sensors due to excellent properties as well as its atomically thin, transparent, and flexible structure. In order to realize the practical applications, graphene needs to be synthesized in a low‐cost, scalable, and controllable manner. Plasma‐enhanced chemical vapor deposition (PECVD) is a low‐temperature, controllable, and catalyst‐free synthesis method suitable for graphene growth and has recently received more attentions. This review summarizes recent advances in the PECVD growth of graphene on different substrates, discusses the growth mechanism and its related applications. Furthermore, the challenges and future development in this field are also discussed.

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Liquid Phase Production of Graphene by Exfoliation of Graphite in Surfactant/Water Solutions

Cited by 2,110 publications

References 37 publications

Tunable sieving of ions using graphene oxide membranes

Tunable sieving of ions using graphene oxide membranes

Solvent Exfoliation of Transition Metal Dichalcogenides: Dispersibility of Exfoliated Nanosheets Varies Only Weakly between Compounds

Controllable Synthesis of Graphene by Plasma‐Enhanced Chemical Vapor Deposition and Its Related Applications

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