Nhigh concentration solvent exfoliation of graphene pdf merger

State key laboratory of polymer materials engineering, polymer research institute of sichuan university, chengdu 610065, china. Dispersed graphene concentration versus solvent surface energy. Surfactantfree exfoliation of graphite in aqueous solutions. Dispersion of graphene in ethanol using a simple solvent exchange methodw xiaoyan zhang,ab anthony c. Pdf the effect of surfactants and their concentration on the liquid. Pdf highconcentration solvent exfoliation of graphene. However, this process can be significantly improved by removing any unexfolaited graphite from the starting dispersion by centrifugation. In contrast, for nonionic surfactants, graphene concentration. Microwaveassisted highyield exfoliation of vanadium. Highly concentrated graphene solutions via polymer enhanced. For example, the sonication of graphite in an organic solvent normally produces a graphene yield of less than 1%. Graphene is easy to acquire, at least in small amounts. A method is demonstrated to prepare graphene dispersions at high concentrations, up to 1. Liquidphase exfoliation of fewlayer graphene and effect.

Highconcentration aqueous dispersions of graphene produced. However, for the end application of exfoliated graphene it needs to extract and redisperse to the required media. Many of the suitable solvents for liquid exfoliation, however, have a high boiling point, which limits. May 15, 2014 direct exfoliation produces high quality graphene layers with good crystalline structure, low defect density, and high electrical conductivity. The mixed solvent of toluene and oleylamine produces higher yield of graphene than its constituents.

Feringaa received 20th july 2010, accepted 23rd august 2010 doi. This process relies on lowpower sonication for long times, up to 460 h. Commercialization of graphene based applications inevitably requires cost effective mass production. Mild sonication of crystal graphite powder in a mixture of water and alcohol could yield graphene nanosheets, which formed a highly stable suspension.

Employing molecular modeling programs, the energetics of exfoliation are modeled and calculated a key aspect to determining the overall reaction rate for graphene production. In this paper, we report on the successful preparation of high quality graphene sheets with a largesize in n,ndimethylformamide dmf solvent by sonicationfree liquidphase exfoliation lpe of graphite assisted with urea as the precursor of the intercalating agent melamine. Production of graphene by exfoliation of graphite in a. Enhancing the liquidphase exfoliation of graphene in organic. Solvothermalassisted liquidphase exfoliation of graphite. University of groningen dispersion of graphene in ethanol. Liquidphase exfoliation of fewlayer graphene and effect of. Effect of processing parameters on graphene concentration.

High concentration of few layer dispersed graphene makes easier its use in many. Synthesis of highquality graphene through electrochemical. Fewlayer graphene obtained by electrochemical exfoliation. Effect of concentration of surfactant on the exfoliation.

High concentration fewlayer graphene sheets obtained by liquid phase exfoliation of graphite in ionic liquid daniele nuvoli, a luca valentini, b valeria alzari, a sergio scognamillo, a silvia bittolo bon, b massimo piccinini, c javier illescas d and alberto mariani a. Kohlhaas a, alfred kleinhammes c, yuanyuan jia c, yue wu c, sonbinh t. In general, the bipolar electrochemical exfoliation method provides a pathway for intercalation on a wider range of. The production of unfunctionalized and nonoxidized graphene by exfoliation of graphite in a volatile solvent, 1propanol, is reported. Research article preparation and characterization of.

In this paper, an effort has been made to demonstrate the preparation of homogeneous and stable dispersion of graphene in odcb solvent. The outstanding processability and electrical properties of these. To confirm the presence of few layer graphene, its dispersion, which exhibits tyndall effect, was characterized by rama chemically modified graphenes. Background history graphene is a flat sheet of carbon just one atom thick. Highyield production of graphene by liquidphase exfoliation of graphite. This is possible because the energy required to exfoliate graphene is balanced by the solventgraphene interaction for solvents whose surface energies match that of graphene. One of the most serious challenge is the lover concentration of graphene dispersions obtained in the pure organic solvents, generally, less than 0. University of groningen graphenebased functional materials.

We used two different concentrations of the surfactant, i. Surfactant molecules can adhere to exfoliated graphene sheets and provide an available repulsive force. In particular, the most effective exfoliation was obtained with 15 volume % of notbz in nmp as a solvent, with a concentration of exfoliated graphene of 250. Modelling the exfoliation of graphite for production of graphene. Very recently, the liquid phase exfoliation of graphene from graphite has been shown as a promising large scale method for graphene production with little to no defects or surface oxides. Mechanical exfoliation to make graphene and visualization. A versatile and scalable mixedsolvent strategy, by which two mediocre solvents could be combined into good solvents for exfoliating graphite, is demonstrated for facile and green preparation of graphene by liquidphase exfoliation of graphite. Chapter 2 preparation of graphene by solvent dispersion methods and its.

Modelling the exfoliation of graphite for production of. Srivastava nanoscience centre, department of physics centre of advanced studies, banaras hindu university, varanasi220005, india abstract. Scalable preparation of lowdefect graphene by urea. One of the most scalable graphene production routes is to exfoliate it from graphite in the liquid phase using ultrasonication, 14, shear mixing 15, wetjet milling 16, or microfluidisation 17. Synthesis of graphenebased nanosheets via chemical reduction of exfoliated graphite oxide sasha stankovich a, dmitriy a. Synthesis of high quality graphene through electrochemical exfoliation of graphite in alkaline electrolyte prashant tripathi, ch. Synthesis of highquality graphene through electrochemical exfoliation of graphite in alkaline electrolyte prashant tripathi, ch. Surfactant mediated liquid phase exfoliation of graphene. Substantial success has been achieved thus far in the lpe of graphene employing numerous solvent systems.

For example, graphene can be produced by supercritical solvent exfoliation of graphite. In order to combine the parameters, we combine them into a single term, r2. Graphene, a 2d honeycomb lattice of carbon atoms, has been the subject of countless studies since its first experimental isolation by mechanical exfoliation in 2004 1,2. During exfoliation sodium cholate was used as surfactant to ease the exfoliation of graphite to graphene. The exfoliation of graphene in liquids by electrochemical. Although, we had promising results at the beginning of this study, it was concluded that the graphene flakes were embedded in the cab films and the cellulose could not be removed. Metal dichalcogenides and their application as supercapacitors, angewandte chemie, 126, 46, 1278412788, 2014. Liquidphase exfoliated graphene for supercapacitors opus 4. The first scientists to isolate the strong, twodimensional carbon material simply pressed a piece of scotch tape to a chunk of graphite and. Solventexfoliated graphene at extremely high concentration. Iterative solvent exchange is further demonstrated as a rapid, roomtemperature, ultracentrifugationfree approach to concentrate the graphene solution to a level exceeding 1 mgml. Exfoliation from bulk, stacked graphite is the most economical way to achieve large quantities of single layer graphene. Modeling the exfoliation rate of graphene nanoplatelet. Highly concentrated graphene solutions via polymer.

In the noncovalent functionalization approach, a comparative study on the liquidphase. Here, we show that graphite spontaneously exfoliates into singlelayer graphene in chlorosulphonic acid, and dissolves at isotropic concentrations as high as. Graphene has been produced by liquid phase exfoliation, which is the most probable method for commercial production of graphene for various industrial applications. Liquidphase exfoliation of graphite to produce high. Fast production of highquality graphene via sequential. For example, a targeted exfoliation of graphite or the stabilization of solvent.

On the other hand, liquidphase shear exfoliation with a highshear mixer is easily available and. We report an effective method for producing graphene sheets using solvothermalassisted exfoliation of graphite in a mixed solvent of toluene and oleylamine. Under these conditions, graphite is exfoliated as highquality graphene 18. Although some liquid phase exfoliation methods report graphene yields as high as 100% 16,17. Besides, the ideal organic solvents discussed above are not volatile and have high boiling points 51. In the present work, the use of a commercial ionic liquid as a convenient solvent medium for graphite exfoliation in mild and easy conditions without any chemical modification is presented. In contrast, for nonionic surfactants, the dispersed graphene concentration. Guided solvent selection to initiate ostwald ripening for interior space. Its extraordinary electrical, thermal, mechanical and optical properties qualified it as a material of choice for applications in electronics 3,4, photonics 5, composites including paints and coating 6,7,8, energy generation. Concentration solvent exfoliation of graphene khan. Jul 10, 2012 a versatile and scalable mixed solvent strategy, by which two mediocre solvents could be combined into good solvents for exfoliating graphite, is demonstrated for facile and green preparation of graphene by liquidphase exfoliation of graphite.

A number of methods have been developed to achieve exfoliation of graphite. Synthesis of graphenebased nanosheets via chemical. Solvothermalassisted liquidphase exfoliation of graphite in a mixed solvent of toluene and oleylamine. Direct exfoliation produces highquality graphene layers with good crystalline structure, low defect density, and high electrical conductivity. Graphene synthesis procedures can follow two different strategies named as bottom up and top down. For example, coleman and coworkers demonstrated the exfoliation of graphene at relatively high concentration in low boiling point solvents such as chloroform and isopropanol 20arlene et al. Surfactantfree exfoliation of graphite in aqueous solutions karen b. In the first one, a carbonaceous carbon material is used to deposite graphene over a substrate and, in the second one, graphite is. Some impurities reside on the graphene after the electrochemical treatment, presumably because of oxidative polymerization of the solvent, as suggested by electron energy loss spectroscopy and xray photoelectron spectroscopy. By employing solvothermalassisted exfoliation in a mixed solvent to control the interactions between solvent molecules and sp 2. Stable highconcentration aqueous dispersions 1 mg ml. Nov 17, 2015 in particular, the most effective exfoliation was obtained with 15 volume % of notbz in nmp as a solvent, with a concentration of exfoliated graphene of 250. Electrochemical exfoliation of graphite in quaternary ammoniumbased deep eutectic solvents.

Si1 supporting information fast production of highquality graphene via sequential liquid exfoliation wei liu a, b, vijesh a. Enhancing the liquidphase exfoliation of graphene in. Solvent strategy for efficient exfoliation of inorganic graphene analogues. Research article preparation and characterization of reduced graphene oxide sheets via waterbased exfoliation and reduction methods vorradaloryuenyong, 1,2 krittotepvimarn, 1 passakorneimburanapravat, 1 wanchaiboonchompoo, 1 andachanaibuasri 1,2. Liquidphase exfoliation of graphite to produce highquality. Graphene dispersions with the concentration up to 0.

The effect of surfactants and their concentrations on the liquidexfoliation of graphene shuai wang1, min yi1, shuaishuai liang1, zhigang shen1,2, xiaojing zhang1 and shulin ma1 1 beijing key laboratory for powder technology research and development, beijing university of aeronautics and astronautics, beijing 100191, china. Graphene dispersion and exfoliation in low boiling point. This paper reports high concentration production of fewlayer graphene in dmso dimethyl sulfoxide as solvent through liquid phase exfoliation assisted with sonication. Highyield electrochemical exfoliation of graphene using high potentials. Spontaneous highconcentration dispersions and liquid. Modelling the exfoliation of graphite for production of graphene mehwish abro the aim of my thesis is to make a theoretical model of data obtained from liquidphase exfoliation of graphene. To ensure most of the microwave energy was concentrated on the v 2 o 5 particles and the adsorbed water molecules during the microwaveassisted exfoliation i. It can be wrapped up into 0d fullerenes, rolled into.

The merits of our approach lie in the quick and complete removal of the remaining solvent from the exfoliated graphitic sheets without the help of high temperature annealing or long vacuum drying. Scalable production of large quantities of defect free. Production of graphene by liquidphase exfoliation of. Organic solvent is suitable for the exfoliation of graphene. Original organic solvents have been used to exfoliate graphene. The effect of surfactants and their concentrations on the liquid exfoliation of graphene shuai wang1, min yi1, shuaishuai liang1, zhigang shen1,2, xiaojing zhang1 and shulin ma1 1 beijing key laboratory for powder technology research and development, beijing university of aeronautics and astronautics, beijing 100191, china. Biodegradable and widely available from renewable sources, cnc have proven to be very efficient graphene stabilizers even at low concentrations 0.

It is possible to achieve concentrations of up to 0. Production of highconcentration graphene dispersions in. Strong bonds link each carbon atom to three other carbon atoms and form hexagonal sixsided shapes. Before the emission current measurement, an electrical conditioning was conducted to get stable eld emission. Efficient graphene exfoliation in a nontraditional solvent, ethanol, is achieved through the addition of a stabilizing polymer, ethyl cellulose. Fast production of high quality graphene via sequential liquid exfoliation wei liu a, b, vijesh a. Graphene, a new 2d material, is gaining a lot of attention because of its remarkable mechanical, electrical, chemical, thermal, and optical properties. The effect of surfactants and their concentrations on the. So, exfoliation using odcb solvent has been chosen. With the to bring graphene from the aim lab to industrial application it is of great. The centrifuged dispersion can be filtered to give a powder of exfoliated fewlayer graphene. Fraunhofer institute for applied solid state physics, tullastra. The exfoliation process and roughening of a flat graphite substrate is directly visualized at the nanoscale by scanning probe and electron microscopy.

Solventbased exfoliation via sonication of graphitic. In this paper, we report on the successful preparation of highquality graphene sheets with a largesize in n,ndimethylformamide dmf solvent by sonicationfree liquidphase exfoliation lpe of graphite assisted with urea as the precursor of the intercalating agent. Graphene sheets resemble a honeycomb or chicken wire. In order to cast light onto the role of the addition of notbz in the graphene liquidphase exfoliation, we first prepared dispersions by adding graphite powder in two different solvents most commonly employed for lpe, i. The third part shows preliminary results on the production of new 2d materials using the solvent based and 1psa based exfoliation methods. Gengzhi sun, juqing liu, xiao zhang, xuewan wang, hai li, yang yu, wei huang, hua zhang and peng chen, fabrication of ultralong hybrid microfibers from nanosheets of reduced graphene oxide and transition. Field emission from fewlayer graphene nanosheets produced by liquid phase exfoliation of graphite dong et al. A study of liquid phase exfoliation and properties of 2d.

Highyield production of graphene by liquidphase exfoliation. State key laboratory of polymer materials engineering, polymer research institute of. The resultant graphene dispersion has a concentration of up to 25. Graphene is a flat monolayer of carbon atoms tightly packed into a twodimensional 2d honeycomb lattice, and is a basic building block for graphitic materials of all other dimensionalities. Electrochemical exfoliation of graphite in quaternary. This occurs without the need for covalent functionalization, surfactant stabilization.

Srivastava nanoscience centre, department of physics centre of advanced studies, banaras. This powder can be redispersed at concentrations of at least 63 mgml. Currently, exfoliation of graphite into gf synthesis mostly involves chemical. A systematic investigation on the effects of exfoliation conditions, including the solvent and the amounts of graphite and hbpe, has been conducted.

Highconcentration solvent exfoliation of graphene request pdf. Understanding the stabilization of liquidphaseexfoliated. High yield production of graphene by liquid phase exfoliation of graphite. The tremendous influence of the experimental procedure sonication time, centrifugation speed and time, stabilizer concentration, etc on dispersed graphene concentration and quality, pointed out by several authors, renders difficult to benchmark the exfoliation efficiency of cnc against reported results for other aqueous stabilizers. The different exfoliation routes of graphite to produce graphene by sonication in solvent, chemical oxidation and electrochemical oxidation are compared. Thus, liquid exfoliation of graphene will become a critically important technology in the near future.

Fewlayer graphene obtained by electrochemical exfoliation of graphite cathode ming zhoua, jie tangb, qian chengb, gaojie xua, ping cuia, luchang qina,c. Liquidphase exfoliated graphene for supercapacitors. Fully exploiting the properties of graphene will require a method for the mass production of this remarkable material. Concentration solvent exfoliation of graphene, small on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at. The production of graphene in the liquid phase exfoliation is a cost efficient method one part of this work is devoted to learn the method of production of. Synthesis of graphenebased nanosheets via chemical reduction. From the early days of research on graphene, direct liquid phase exfoliation lpe of graphite has been considered as the most promising strategy to produce high quality mono or fewlayer graphene sheets in solvent dispersion forms. High yield and high concentration fewlayer graphene sheets. A comparative study on fewlayer graphene production by. Preparation of highquality graphene with a largesize by. Solvothermalassisted liquidphase exfoliation of graphite in. High yield and high concentration fewlayer graphene. Concentration of graphene produced via highshear mixing in various solvents.

Highyield electrochemical exfoliation of graphene using high. This value of graphene concentration for the mixed solvent of toluene and oleylamine is higher than that. Chemical exfoliation of graphene and other 2dmaterials. Concentration solvent exfoliation of graphene, small. In this thesis, the liquid phase exfoliation of graphene from bulk graphite is studied through computational simulations and subsequent entropy and rate calculations. From the early days of research on graphene, direct liquid phase exfoliation lpe of graphite has been considered as the most promising strategy to produce highquality mono or fewlayer graphene sheets in solvent dispersion forms. Aug 10, 2008 fully exploiting the properties of graphene will require a method for the mass production of this remarkable material. Highyield electrochemical exfoliation of graphene using.