Hybrid structures have attracted much interest recently because of their advantageous properties. Structure and synthesis of graphene oxide sciencedirect. The chemistry of the graphene based material was tuned, both through thermal and electrochemical reduction of graphene oxide. Crystal structure of graphite, graphene and silicon. Notably, existing highresolution transmission electron microscopy hrtem studies of graphene oxide report longrange order of sp2 lattice with isolated defect clusters. Pdf structure and energetics of graphene oxide isomers. Jan 22, 2021 herein, we introduce a simple method to prepare hierarchical graphene with a tunable pore structure by activating graphene oxide go with a twostep thermal annealing process. These graphene oxides have important applications in areas related to transparent conductive film, composite materials, solar energy and biomedical applications. Effect of graphene oxide size and structure on synthesis and. This study introduces a new structural model of graphene oxide and its theoretical electronic properties. Although some oxygen functional groups ofgs are accepted as the main functionalities in go, the structure of go has remained elusive. Particular emphasis is directed toward the synthesis of graphene oxide, as well as its structure. Research article the resistive switching behavior of alchitosan graphene oxide fto structure hau huu do ho,1,2 trung minh le,1,2 and ngoc kim pham 1,2 1faculty of materials science and technology, university of science, ho chi minh city, vietnam 2vietnam national university, ho chi minh city, vietnam correspondence should be addressed to ngoc kim pham. Synthesis and characterization of structure of fe3o4.
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 and acids for resolving of extra metals. The effect of graphene oxide dispersion on structure. However,overoxidation of the carbon framework hamperedestablishing structure property relationships. As it is seen on figure 1 a presence of amorphous halo at 2.
The main simulation and computation theories to establish these structure. As an alternative, compounds similar in structure to graphene can be synthesized from graphite or other carbon sources by a topdown method in an effort to. Mar, 2009 crystal structure of graphite, graphene and silicon dodd gray, adam mccaughan, bhaskar mookerji. Summary of graphene and related compounds chemical and. Graphene oxide as a substrate for a variety of chemical transformations, including its reduction to graphene like materials, is also discussed. Pdf atomic and electronic structure of graphene oxide. Introduction to the physical properties 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 graphite layer, and then in 1946, ruess 21. Hygroscopicity and dispersibility are the main properties of go. March, 2009 we analyze graphene and some of the carbon allotropes for which graphene sheets form the basis. First one is fundamental study of graphite oxides go structure and properties. Structure and photocatalytic properties of tio2graphene.
Graphene synthesis, properties, and applications cheap tubes. The present work investigates the effect of the dispersion of graphene oxide upon the structure property relations in metallocene linear low density polyethylene pe, homo polypropylene pp, and blends thereof. The structure of go is often simplistically assumed to be a graphene sheet bonded to oxygen in the. Synthesis of graphene oxide go by modified hummers. Chemical structures of hydrazinetreated graphene oxide. Graphene oxide could potentially be used as an intermediary in the production of single layer or fewlayer graphene sheets. Graphene oxide is also a nanosized particle which gives it an extremely high surface area so when it is dispersed in water the chances of the contaminant coming in contact and adsorbing to the graphene oxide particle is high.
Determination of the local chemical structure of graphene. To improve its dissolving property, graphene could be modified via oxidization into graphene oxide go 4,5. 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. Graphite oxide, formerly called graphitic oxide or graphitic acid, is a compound of carbon.
The realspace and reciprocal crystalline structures are analyzed. Graphite oxides for preparation of graphene related materials diva. Aksay z adepartment of chemical and biological engineering, princeton university, princeton, new jersey 08544, usa. Jan 27, 2010 determination of the local chemical structure of graphene oxide and reduced graphene oxide. This book focuses on a group of new materials labeled graphene oxides. A heating chip containing a platinum coil a was used to study the temperature dependence of the structure. Number of manuscripts with graphene in the title posted on the preprint server. Aug 17, 2010 the local atomic structure of graphene oxide go and reduced annealed graphene oxide rago is determined via ultra. Pdf graphene oxide go can be regarded as one typical twodimension structured oxygenated planar molecular material. Researchers across multiple disciplines have paid enormous attention to it due to the unique physiochemical properties. Using different degrees of thermal reduction, we can tune the oxygen content and lattice disorder. 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. Atomic and electronic structure of grapheneoxide nano letters. Pdf structure and synthesis of graphene oxide alan.
Graphene oxide structure and theoretical simulation2. Pdf structure and synthesis of graphene oxide researchgate. It is an allotrope of carbon in the structure of a plane of sp2 bonded atoms with a molecule bond length of 0. Graphene exhibited outstanding structural 11, electrical. Electron diffraction shows that on average the underlying carbon lattice maintains the order and latticespacings of graphene. The combination of chitosan cs and graphene oxide go acts as switching layers in the alcsgofto rram structure it is studied with bipolar switching behavior at approximately 102 onoff ratios during 100 cycles. However, models used to describe the structure of go are still in dispute and ongoing to update. Both open monolayer, low contrast and closed figure 1. This ability can be used as an agent for dispersion of insoluble materials such as carbon nanotubes4. The maximally oxidized bulk product is a yellow solid with c. At this moment, the name graphene was not commonly used. The performance of graphene polymer nanocomposites depends on many factors but the major factor is a nanoparticles dispersion and distribution into the host matrix. Zettl university of california at berkeley and, materials sciences division lawrence berkeley national laboratory berkeley, ca 94720 usa email. Graphene oxide go and reduced go rgo are the only variants of graphene that can be manufactured at the kilogram scale, and yet the widely accepted model for their structure has largely relied on indirect evidence.
Partial density of states and electronic plasma excitations are also measured for these go sheets showing unusual. Emphasis is placed on the molecular structure of graphene oxide, synthetic methods, impurities, properties, mechanistic insights, reagents, different carbon. The complexity and variety of go isomers, whose thermodynamic stability and formation kinetics depend on the applied conditions, make determination of the go. Graphene oxide s properties include the ability to act as a surfactant, similar to how soap or shampoo would make a stain disperse in water. Surface functional groups of go layers and the oxidative debris od stacked on them were investigated after od was extracted. 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.
The nucleation and growth of tio 2 crystallites took place at low temperature and tio 2 graphene oxide composite was successfully synthesized. Graphene oxide is a singlelayer material with a high oxygen content. The membranes in swelled state are also permeable by gases, e. Structure dependent electrochemistry of reduced graphene oxide monolayers christian punckt, a,b,c michael a. These results also reveal that single go sheets are highly electron. Our results provide new insight into the structure of graphene oxide and indicate that in addition to the removal of oxygen, structural ordering of the remaining graphene sheets is necessary if high mobilities from reduced graphene oxide devices are to be achieved. Hrtem micrograph of reduced graphene oxide sheets fig. Preparation and characterization of graphene oxide from tea waste.
A number of different models for graphene oxide have been proposed and tested using ab initio calculations. The structural and optoelectronic properties of p3htgraphene composites prepared by in situ oxidative polymerization were studied by saini et al. Such disorder in the graphene structure leads to many unique properties of. 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. These properties make graphene oxide an excellent candidate for removing large amounts of pcbs from our water sources. Summary of graphene and related compounds chemical.
The exact process parameters used when reducing go into rgo play a major role in the quality of the material, affecting how close a structure to perfect graphene is achieved. Graphene oxide go is one typical twodimension structured and oxygenated planar molecular material. Structure of graphene oxide membranes in solvents and solutions. Synthesis of graphene oxide go by modified hummers method. 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. 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. In interpreting these numbers, one must, however, consider that several publications on graphene appeared before 2006, e. Pseudo3d representation of a 600 nm 600 nm afm scan of an individual graphene sheet showing the wrinkled and rough structure of the surface, and an atomistic model of the graphite oxide to.
Structure of graphene oxide membranes in solvents and solutions alexey klechikov,a junchun yu,a diana thomas,b tiva shari. In 1936, hofmann and rudolf 22 proposed the first go structure figure 1, the topleft 1st. Furthermore, the photocatalytic properties of tio 2 graphene oxide under the irradiation of uv light were also studied. To achieve this, an oxidization and reduction process should be developed that can isolate carbon layers and separate then without changing their structure. Modified structure of graphene oxide by investigation of.
One of the most important traits of go is that it can be produced using graphite since it is inexpensive using different chemical methods, yielding a high production with exceptional costefficiency. The structure and properties of graphite oxide depend on particular sy. This chapter introduces a peculiar carbon compound previously named as graphitic acid, graphite oxide go, or more recently, graphene oxide go. A number of models were proposed for the go structure, combining carboxyl, hydroxyl, carbonyl and epoxide groups at different locations. In summary, in order to turn graphene applications into reality, one must fabricate the material. Permeation of graphite and graphene oxide membranes by polar solvents is possible due to swelling of the graphite oxide structure. In this regard, go was produced using the modified hummers method and was investigated using xray diffraction pattern, fourier.
Layers of graphene stacked on top of each other form graphite, with an. The effect of graphene oxide dispersion on structureproperty. Even today, the go structure model is still controversial. Graphene oxide sheets are chemically reactive in liquid water, leading them to acquire a small negative charge. Graphene oxide go holds significant promise for electronic devices and nanocomposite materials. Chemical, structural, and vibrational properties are discussed through xray photoemission spectroscopy and raman spectroscopy studies. We find that the proposed and desired return to graphene from go is not possible through the synthetic route employed. Finally, chemical structure of go sheet was also described in this study. Graphene oxide as a substrate for a variety of chemical transformations, including. The next three sections describe the three types of chemical methods.
Research article preparation and characterization of. Theoretical models for structures of graphite or graphene oxide. A theoretical study of graphene oxide chemical structure. The preparation of graphene oxide and its derivatives and their.
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. Huh 30 this is amorphouslike carbon which comprises many defects, folding structures, impurities, sp1, sp2, and sp3 hybridization. Synthesis and characterization of graphene oxide and reduced. Due to their outstanding physical, thermal, and electrical properties, these papers have promising applications such as. Chemistry and structure of graphene oxide via direct imaging. Here, the fact that two different synthetic methods for graphene oxide preparation lead to very similartypes of graphene oxide with apreserved graphene lattice is demonstrated. The resistive switching behavior of alchitosangraphene. Pdf chemistry and structure of graphene oxide via direct. Figure 1a shows the structure of a single layer graphene and figure 1b shows the structure of graphene oxide.
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. The structures and topographies of graphite oxide and go can be. We report on the structural analysis of graphene oxide go by transmission electron microscopy tem. Chemical structures of hydrazinetreated graphene oxide and. However, graphene is hydrophobic, which inhibits its function in the water. Atomic and electronic structure of grapheneoxide nano. Structure and chemistry of graphene oxide in liquid water. Structuredependent electrochemistry of reduced graphene. Synthesis, properties, and applications of graphene oxidereduced.
Analysis was performed successfully using fourier transform. Structure of graphene oxide membranes in solvents and. The bulk material disperses in basic solutions to yield monomolecular sheets, known as graphene oxide by analogy to graphene, the singlelayer form of graphite. Research article preparation and characterization of graphene. The graphene obtained by reduction of graphene oxide still has many. Tuning the hierarchical pore structure of graphene oxide. Dec 03, 2015 the structure of graphite oxide and graphene oxide go has been studied previously using various analyses and computer simulations. Nov 21, 2017 the graphene oxide molecular structure consists of carbon, hydrogen and oxygen. Structural analysis of reduced graphene oxide by transmission. It provides a comprehensive overview of graphene oxidebased nanomaterials in terms of their synthesis, structures, properties. Due to the presence of oxygen groups bonded to the. Nov 10, 2016 graphite oxide, formerly called graphitic oxide or graphitic acid, is a compound of carbon, oxygen, and hydrogen, obtained by treating graphite with strong oxidizers.
1457 346 448 10 346 1132 912 978 205 1472 1454 411 567 241 1323 1205 1326 796 533 649 200 447 1302 434 772 1114 239 1091 864 49 865 403 443 1499 449