Graphene oxide, 1520 sheets, 410% edgeoxidized, 1 mgml, dispersion in h2o. Structure and properties of nibgraphene oxide composite. This article presents that go sheets reduced by high. Electronic properties and atomic structure of graphene oxide.
Atomic and electronic structure of go graphene go nanoshtheet graphene ideal structure reduction distorted 3sp sp2 planar insulator. March, 2009 we analyze graphene and some of the carbon allotropes for which graphene sheets form the basis. Mar 26, 2020 graphene oxide go is a graphene based material that has gained significant interest in the last two decades 1,2 due to its straightforward, scalable, and lowcost synthesis. Researchers across multiple disciplines have paid enormous attention to it due to the unique physiochemical properties. Crystal structure of graphite, graphene and silicon. The electrical, thermal, optical, mechanical properties of graphene and graphene oxide, as well as the common tools for characterization of graphene and its derivatives are also discussed. Go, namely graphene oxide, 30 and of the chemistry of graphene. A theoretical study of graphene oxide chemical structure. Graphene was characterized by singlelayered flakes about 0. Hygroscopicity and dispersibility are the main properties of go. The structure of graphene oxide is still unclear due to its complicated nonstoichiometric nature. A number of different models for graphene oxide have been proposed and tested using ab initio calculations. Pdf structure and synthesis of graphene oxide alan. An eightvolume set of handbooks on graphene research and applications.
Effect of structure on the tribology of ultrathin graphene. Among all studies on the chemistry of go, the largest portion focused on the reduction of go back to graphene, mainly due to its high relevance to graphene and the gold rush of graphene research over the last decade. Pdf graphene oxide go can be regarded as one typical twodimension structured oxygenated planar molecular material. Structure of graphene oxide membranes in solvents and. Electronic properties and atomic structure of graphene oxide membranes d. Nov 10, 2016 graphene oxide, the monomolecular sheets of graphite oxide is a compound of carbon, oxygen, and hydrogen in variable ratios, obtained by treating graphite with strong oxidizers. Determination of the local chemical structure of graphene oxide and reduced graphene oxide. Synthesis of graphene oxide scientific research publishing.
This study introduces a new structural model of graphene oxide and its theoretical electronic properties. Surface functional groups of go layers and the oxidative debris od stacked on them were investigated after od was extracted. The main simulation and computation theories to establish these structure. Abstract graphene oxide go is one typical twodimension structured and oxygenated planar molecular material. Synthesis of chitosan beads incorporating graphene oxide. Zettl university of california at berkeley and, materials sciences division lawrence berkeley national laboratory berkeley, ca 94720 usa email.
Discussion and references for further research on graphene are. To understand the configuration and arrangement of hydroxyls and oxygens on the go layers, lahaye et al. Keywords graphene oxide, transmission electron microscopy, defects s ince the discovery of graphene,1 a twodimensional atomic sheet entirely made of carbon, immense efforts have been directed toward the development of reliable methods for obtaining large quantities of this extraordinary material. Such type of fi lm is used as segment in fi eldeff ect transistor 27. And currently, synthesis methods for mass production are seemingly. Keywords graphene oxide graphene sheet scan tunneling microscope graphite oxide graphene film. However, the low electrical conductivity of reduced go is still hindering the development of electronic applications. The chemical composition of oxidized patches is revealed by our nexafs investigation. Graphene oxide go layers are the individual sheets of conventional graphite oxide cgo synthesized from graphene. Structure of graphene oxide membranes in solvents and solutions alexey klechikov,a junchun yu,a diana thomas,b tiva shari. In interpreting these numbers, one must, however, consider that several publications on graphene appeared before 2006, e. The representative structure of graphene oxide nanoflakes. In this chapter, we discuss a variety of chemical reactions introduced for go.
Graphene oxide synthesized by oxidizing natural graphite was reduced by ascorbic acid which is a green reducer. The coatings produced were characterized by an amorphous structure. This element is unique in that its unique electronic structure allows for hybridization to build up sp3,sp2, and sp networks and, hence, to form more known stable allotropes than any. Morphology and structure the graphene honeycomb lattice is. Introduction graphene can be described as a one atom thick layer of graphite. Pdf structure and synthesis of graphene oxide researchgate. Graphene oxide sheets have been used to prepare a strong paperlike material, and have recently attracted substantial interest as a possible intermediate for the. Theoretical models for structures of graphite or graphene oxide. The materials obtained are remarkable in terms of the particles size homogeneity and dispersion onto the reduced graphene oxide surface. The purpose of this work is the structural analysis of graphene oxide go and by means of a new structural model to answer the questions arising from the lerfklinowski and the lee structural models.
Analysis was performed successfully using fourier transform. We hypothesized that graphene oxide would be a promising coating material for perfluorinated surfaces for two reasons. It has been well established that the performance of go is strongly coupled to degree and type of oxidation, and virtually all of physical. For the 10 go structures displayed in figure 1, we rst checked their structural stability and energetics in vacuum by carrying out a series of structure optimizations see. Structure and synthesis of graphene oxide sciencedirect. Synthesis of graphene oxide go by modified hummers. There are different kinds of oxygen species and bondings to carbon in graphene layer, such as epoxy, hydroxyl, carbonyl, carboxylic groups fig. Talyzina the change of distance between individual graphene oxide sheets due to swelling is the key parameter to explain and predict permeation of multilayered graphene oxide go membranes by various. Graphene oxide as a substrate for a variety of chemical transformations, including its reduction to graphene like materials, is also discussed. Graphene oxide go has been initially prepared by a modified hummersmethod. The realspace and reciprocal crystalline structures are analyzed.
Chemistry and structure of graphene oxide via direct imaging. The main difference between graphite oxide and go is, thus, the number of layers. Graphene oxide structure and theoretical simulation 2. There have been countless studies on the properties of graphene oxide go 14 for electrochemical, biomedicine, sensing, catalysis, energy and environmental applications. Structurally, graphene oxide can be visualized as a graphene sheet with its basal plane decorated by oxygencontaining. Particular emphasis is directed toward the synthesis of graphene oxide, as well as its structure. These graphene oxides have important applications in areas related to transparent conductive film, composite materials, solar energy and biomedical applications. Electronic properties and atomic structure of graphene. However, models used to describe the structure of go are still in dispute and ongoing to update. Subsequently reduced graphene oxide rgo having few layer graphene is extracted from go by the thermal reduction of go.
Graphite oxide is one of the main precursors of graphene based materials, which are highly promising for various technological applications because of their unusual electronic properties. Solutionbased processes involving the chemical oxidation of graphite and reduction of the obtained graphene oxide go sheets have attracted much attention for preparing graphene films for printed electronics and biosensors. This thesis proposes a modified structure model for graphite oxide go, an important precursor in graphene chemistry, develops a new strategy to convert go. Graphene is a 2dimensional honeycomb lattice of sp2bonded carbon atoms and has received enormous interest because of its host of interesting material properties and technological potentials. This comprehensive volume systematically describes the fundamental aspects and applications of graphene oxide. Having unique properties, graphene layers are a quite interesting nanomaterial for industrial applications. Mar 18, 2020 an innovative strategy is proposed to synthesize single. Atomic and electronic structure of grapheneoxide nano.
We clearly distinguish between onplane functionalization defects and inplane. At the beginning of graphene history go was only a simple and cheap step for preparation of single and multilayer graphene films and bulk structures by reduction. Jan 28, 2019 graphene oxide go is useful and promising material for graphene based applications in electronic, optics, chemistry, energy storage, and biology. Graphene is the strongest, thinnest material known to exist. Moreover, the synthesis method used to obtain the graphene oxide clearly affects the performances of the final composites through the control of the restacking of the reduced graphene oxide sheets. Atomic and electronic structure of grapheneoxide nano letters. Graphene oxide could potentially be used as an intermediary in the production of single layer or fewlayer graphene sheets.
Though chemicallyreduced graphene oxide had previously been coated with metallic nanoparticles via electrodeposition, representing one of the few uses of cmgs in electrochemistry, 67 only recently has electrochemical reduction been used to alter the structure of graphene oxide or graphene itself. Mar 12, 2020 graphene in the form of an aqueous suspension of graphene oxide flakes was used. Structure and chemistry of graphene oxide in liquid water. The incorporation of graphene into the nib matrix affects the surface topography and morphology of the coatings produced. At this moment, the name graphene was not commonly used. Graphene oxide go, as an emerging star nanobuilding material, has showed great potential in the membranebased separation field. Synthesis of graphene oxide go by modified hummers method. Highly efficient restoration of graphitic structure in. Recently, graphene oxide go, which was prepared by chemically oxidizing graphite to graphite oxide gto with strong oxidants and ultrasonic cleavage, has attracted much attention as a possible intermediate for manufacture of graphene in large volume. Natural flake graphite nfg was procured from loba chemie india having a mean size of 60 mesh and purity of 98%. We elucidate the atomic and electronic structure of graphene oxide go using annular dark field imaging of single and multilayer sheets and electron energy loss spectroscopy for measuring the fine structure of c and o kedges in a scanning transmission electron microscope. Recent developments of graphene oxidebased membranes. A heating chip containing a platinum coil a was used to study the temperature dependence of the structure.
The development of novel membrane materials and membrane structures is an urgent demand to promote membranebased separation technology. Valenceband electronic structure evolution of graphene. In 1936, hofmann and rudolf 22 proposed the first go structure figure 1, the topleft 1st schematic structure in which a deal of epoxy groups are randomly distributed on. The energy oxide paper was made at a liquidair interface by evaporating quantization of the graphene electronic structure in a magnetic g the hydrosol of. This demonstrates the potential of tailoring the structure of go to achieve graphenelike tribological properties. The structure and morphology of both go and rgo were analyzed using xray diffraction xrd, scanning electron microscopy sem, high. This process is experimental and the keywords may be updated as the learning algorithm improves. The maximally oxidized bulk product is a yellow solid with c.
An adf image of a graphene with oxygen atoms attached to both side of the sheet was simulated and the resulting image is shown in figure 2e. Synthesis, structure, and properties of graphene and. Structure dependent electrochemistry of reduced graphene oxide monolayers christian punckt, a,b,c michael a. To achieve this, an oxidization and reduction process should be developed that can isolate carbon layers and separate then without changing their structure. Graphene oxide is the oxidized form of graphene with the oxygencontaining function groups decorating the sp 2 c basal plane 14. New insights into the structure and reduction of graphite oxide.
In order for graphene oxide to be usable as an intermediary in the creation of monolayer or fewlayer graphene sheets, it is important to develop an oxidization and reduction process that is able to separate individual carbon layers and then isolate them without modifying their structure. Analogous to carbon nanotubes network structures, the graphene and graphene oxide sheets can be assembled into multi layered network structures which can. Natural flake graphite nfg was procured from loba chemie india. Both open monolayer, low contrast and closed figure 1. From fundamentals to applications article pdf available in journal of physics condensed matter 271. Despite these excellent properties, purely singlelayer graphene achieves limited success in practical applications due to the difficulties in the largescale. The book is designed as an introduction to the topic, so. We elucidate the atomic and electronic structure of graphene oxide go using annular dark. Graphene oxide is the oxidized form of graphene produced by oxidizing crystal graphite with a mixture of sulfuric acid, sodium nitrate, and potassium permanganate the hummers method. Number of manuscripts with graphene in the title posted on the preprint server.
Chemical, structural, and vibrational properties are discussed through xray photoemission spectroscopy and raman spectroscopy studies. Introduction to the physical properties of graphene. The further studies revealed the substantial structure imperfection of graphene oxide. The structure of graphene oxide is critical to its performance in a variety of applications, and so the configuration of model structures is also critical to predictions made in advance of synthesis and characterization.
Structuredependent electrochemistry of reduced graphene. It is the basic structural element of other allotropes, including graphite, charcoal, carbon nanotubes and fullerenes. Sigmaaldrich offers a number of graphene oxide products. Aug 18, 2019 graphene oxide is an excellent material to solve this problem 4,5,6. Adf images of graphene with three double bonds of oxygen to carbon atoms and one with a single bond are shown in figure 2ad, respectively. Crystal structure of graphite, graphene and silicon dodd gray, adam mccaughan, bhaskar mookerji. Keywords fermi level, graphene oxide, optoelectronic, ultraviolet photoelectron spectroscopy, valenceband electronic structure corresponding author. In 1936, hofmann and rudolf 22 proposed the first go structure figure 1, the topleft 1st schematic structure in which a deal of epoxy groups are randomly distributed on the graphite layer, and then in 1946, ruess 21. Synthesis, structure, and properties of graphene and graphene. Graphene oxide, powder, 1520 sheets, 410% edgeoxidized.
Due to its unique properties, graphene oxide has become one of the most studied materials of the last decade and a great variety of applications have been reported in areas such as sensors, catalysis and biomedical applications. Simultaneously, chemical structure of go sheet was described in this study. Th is nanometerthick thin fi lm consist few graphene oxide sheets which can be mono, bi, and tri layers of graphene oxide. Graphite oxide, formerly called graphitic oxide or graphitic acid, is a compound of carbon, oxygen, and hydrogen in variable ratios, obtained by treating graphite with strong oxidizers. Partial density of states and electronic plasma excitations are also measured for these go sheets showing unusual. This set features volumes 1, 2, 3, 4, 5, 6, 7, and 8 of the handbook of graphene. What is the actual structure of graphene oxide nanoflakes. Lowvoltage, highresolution tem was used to directly observe the structure of graphene oxide. In 1939, hofmann and rudolf demonstrated a structural model of go fig. Morphology and structure the graphene honeycomb lattice is composed of two equivalent. Previous nexafs studies described the electronic structure and chemical composition of bulk graphite oxide 17 and of electrophoretically deposited graphene oxide and. Graphene oxide go is a graphenebased material that has gained significant interest in the last two decades 1,2 due to its straightforward, scalable, and lowcost synthesis.