Synthesis and characterization of graphene thin films by. Ruoff a, a department of mechanical engineering and the texas materials institute, the university of texas at austin, one university station c2200, austin, tx 787120292, usa b department of chemistry, inha university, incheon 402751, republic. Highquality graphene via microwave reduction of solution. Graphenothermal reduction synthesis of exfoliated graphene oxideiron ii oxide composite for anode application in lithium ion batteries. Here we demonstrate a simple and fast method of electrochemical exfoliation of graphite to graphene oxide go and then its rapid reduction to graphene nanosheets gns with the help of microwaves. In particular, we present evidence to support the claim that go can be completely exfoliated into individual graphene oxide sheets and that chemical.
Introduction study of carbon nanostructures is very extensive due to their unmatched properties and numerous applications. Request pdf thermally exfoliated graphene oxide for hydrogen storage this study investigated the effect of structural changes of thermally exfoliated graphene oxide on its hydrogen uptake. Effect of ambient gas pressure on the thermal exfoliation of. These results are in near concord with results reported earlier graphene at different diffraction peaks varies from 32. The authors tried to interpret the obtained physicochemical results. Ftir graphs in the wavenumber range of 150018500 cm1 pdf. Chemical synthesis is the similar process which consists of the synthesis of graphite oxide, disper.
Exfoliated graphite oxide decorated by pdmaema chains and. What is the difference between graphite oxide and graphene. The difficulty in the formation of a confined structure, and the numerous and diverse oxygen. Exfoliated graphene oxidebased nanofluids with enhanced thermal and optical properties for solar collectors in concentrating solar power. Pdf today, research on graphene and other twodimensional sp2hybridized carbon nanomaterials has tremendously impacted the areas of modern chemistry. Graphene oxide solutions of desired concentration or graphene oxide paper or sheet can be made from graphene oxide paste. Mechanical exfoliation to make graphene and visualization. Synthesis of graphenebased nanosheets via chemical reduction of exfoliated graphite oxide sasha stankovich a, dmitriy a. Exfoliated graphene oxide go reinforced natural rubber nr composites were prepared by a simple and promising latex cocoagulation method. Preparation via rapid, mild thermal reduction of graphene oxide and application in lithium batteries zuyun luo 1,2, yuanyuan li 1, fangfang wang 1 and ruoyu hong 1, 1 college of chemical engineering, fuzhou university, fuzhou 350116, china. Background history graphene is a flat sheet of carbon just one atom thick. Exfoliated graphite nanoplatelets xgnp are new types of nanoparticles made from graphite. Pdf synthesis of graphene nano sheets by the rapid.
The exfoliated graphene oxide was prepared by stirring 1g of powdered exfoliated graphite eg flakes and 50 mg of sodium nitrate into 23 ml of concentrated sulphuric acid. Electrochemically exfoliated graphene and graphene oxide for. To address this issue various graphite forms solid, powder and sooth and graphite oxide powder are exfoliated in acetonitrile and studied via ultravioletvisible uvvis spectroscopy. A thiol functional group facilitated the interaction with hgii, resulting in efficient adsorption. Sigmaaldrich offers a number of graphene oxide products. Sep 23, 2016 efficient exfoliation of graphite in solutions to obtain highquality graphene flakes is desirable for printable electronics, catalysis, energy storage, and composites. Fast and fullyscalable synthesis of reduced graphene oxide.
Herein, we describe the detailed process for the reduction of exfoliated go sheets with hydrazine and the characterization of the resulting material. Preparation and characterization of reduced graphene oxide. The assynthesized egmno composite is constituted with 65 and 35 wt % of mno and eg. These graphene oxides have important applications in areas related to. Poly2dimethylaminoethyl methacrylate pdmaema chains on the surface of. Nanomaterials highqualitygraphene via microwave reduction of. Synthesis of graphene based nanosheets via chemical reduction of exfoliated graphite oxide sasha stankovich a, dmitriy a. Latex cocoagulation realized the complete exfoliation and uniform dispersion of go in a nr matrix. Extrinsic wrinkling and single exfoliated sheets of. Thermally exfoliated graphene oxide for hydrogen storage. Exfoliated graphene oxidebased nanofluids with enhanced. Despite the fact that there have been many studies of graphite exfoliation, none really addresses the issue of starting form of graphite.
Le and others published cufe incorporated graphene oxide nanocomposite as highly efficient catalyst in the degradation of. Porous three dimensional microwave exfoliated graphene oxide 3dmego structure was synthesized following a previously reported procedure supporting information. We supply special pricing for largequantity orders across a wide range of industries. The formation of different submicron sized morphologies such as spheres, rods, flowers, etc. The spectra in figures 2a and 2b show two peaks corresponding to graphene oxide and graphene. Potts a, aruna velamakanni a, shanthi murali a, rodney s.
Our results confirm the presence of wellexfoliated sheets that are key to achieving high interfacial areas between polymers and high aspect ratio filler in. The exfoliated gomg flakes were processed and incorporated in an elastomeric polyurethane pu matrix. In this manner, graphene oxide as a substrate for graphene like materials reduction process is getting more and more interesting. Exfoliated graphene oxide based nanofluids with enhanced thermal and optical properties for solar collectors in concentrating solar power. Be wary of nomenclature mismatches during this period. Functionalized exfoliated graphene oxide as supercapacitor. Oxidation of graphite effectively facilitates the exfoliation process, yet necessitates several lengthy washing and reduction processes to convert. We show that the local graphene oxide structure in these polymergraphene oxide nanocomposites is identical to that of graphene oxide in a water solution studied on the same length scale. Their surface morphologies were observed by scanning electron microscope. Neutron scattering study of nickel decorated thermally.
This graphene oxide paper is based on nanoscale graphene oxide sheets that are interlocked and tiled together in a nearparallel fashion. The samples prepared by this method were characterized with different techniques such as ultra violetvisible. It is also interesting to note that graphite rod sample has thinner graphene oxide dispersions than graphite powder sample. Synthesis and characterization of exfoliated graphene oxide. Effect of ambient gas pressure on the thermal exfoliation. Local current mapping of electrochemicallyexfoliated graphene oxide by conductive afm to cite this article. Among the various species of carbon, graphene is one of the. Hummers method is one of the most common methods used in synthesizing graphene oxide. Simple preparation of exfoliated graphene oxide sheets via. Graphene sheets resemble a honeycomb or chicken wire. Graphene, a novel oneatomthick carbon material arranged in a hexagonal honeycomb lattice, has attracted tremendous attention in the fields of academia and industry. In addition, because of the large amount of oxygencontaining functional groups 7, go shows excellent hydrophilicity, and is relatively easily dispersed in water and even in other solvents through further modi. Graphene has become a promising filler in rubber composites owing to its large theoretical specific surface area, high youngs modulus, and excellent electrical and thermal conductivities. Unsaturated edgeanchored ni single atoms on porous microwave.
Pdf cufe incorporated grapheneoxide nanocomposite as. Graphene oxide multilayer graphene gomg flakes were obtained using an electrochemically exfoliated graphite gr electrode from secondary steelmaking industry performed in a twoelectrode system using tungsten as the counter electrode and gr as the working electrode. Massive production of graphene oxide from expanded graphite arxiv. Reduction of a colloidal suspension of exfoliated graphene oxide sheets in water with hydrazine. Synthesis of graphenebased nanosheets via chemical reduction. We demonstrated that the graphite did not need to be oxidized to such a deep degree as described in hummers method because the space distance increased little when the oxidation proceeded to a certain extent and the obtained graphite oxides gtos could. Pdf simple preparation of exfoliated graphene oxide sheets. Fewlayer graphene obtained by electrochemical exfoliation of graphite cathode ming zhoua, jie tangb, qian chengb, gaojie xua, ping cuia, luchang qina,c. What is the difference between graphite oxide and graphene oxide.
Atom transfer radical polymerization atrp initiator molecules were grafted onto the go sheets by reactions of 2bromo2methylpropionyl bromide with hydroxyl groups and amine groups. The ambience gas ar pressures used are 80, 25, 1 atmosphere and 103 as well as 105 torr. Pdf graphenothermal reduction synthesis of exfoliated. Xray diffraction of graphene oxide and reduced graphene oxide synthesized by chemical reduction of exfoliated and intercalated graphite oxide is presented in figure 2. These nanoparticles consist of small stacks of graphene that are 1 to 15 nanometers thick, with diameters ranging from submicrometre to 100 micrometres. This makes sense since graphene oxide eventually results in graphene layers after the oxide removal. Graphene oxide has many applications such as in electronic devices, as storage energy device, biosensor, biomedical application, water purification, coating technology, as a composite and paper like materials.
Simple synthesis of large graphene oxide sheets via. Graphene oxidemultilayergraphene gomg flakes were obtained using an electrochemically exfoliated graphite gr electrode from secondary steelmaking industry performed in a twoelectrode system using tungsten as the counter electrode and gr as the working electrode. Exfoliated graphene oxide egmanganeseii oxide mno composite powder is synthesized by simple solid state graphenothermal reduction process. Synthesis of graphenebased nanosheets via chemical reduction of. Studies of physicochemical properties of graphite oxide. Finally, the oxygen functional groups on exfoliated graphite oxide or graphene oxide were eliminated by stirring in hot distilled water at 95c, as a replacement for highly toxic and dangerously unstable hydrazine.
Today, research on graphene and other twodimensional sp2hybridized carbon nanomaterials has tremendously impacted the areas of modern chemistry, physics, and materials science and engineering. The second step is the oxidation step, where oxidation of exfoliated graphene sheets was. Graphene oxide quantum dots exfoliated from carbon fibers. Synthesis of graphene oxide go by modified hummers method. What is difference between graphene oxide and exfoliated. Low yields of singlelayered graphene, submicrometer lateral dimensions, and poor electronic properties remain as major challenges for solutionexfoliated graphene flakes 14.
Electrochemically exfoliated graphene and graphene oxide. Structural and morphological characterizations of ego have been carried out using xray diffraction xrd, scanning electron microscopy sem, ftir and raman spectroscopy. Highyield scalable graphene nanosheet production from. Functionalized exfoliated graphene oxide ego for supercapacitor electrodes have been synthesized by simple chemical methods from the exfoliated graphite eg as precursor.
Kohlhaas a, alfred kleinhammes c, yuanyuan jia c, yue wu c, sonbinh t. The aim of the experimental research studies was to determine some electrical properties of graphite oxide and thermally exfoliatedreduced graphene oxide. We keep researching and developing our chemically exfoliated graphene to. Fewlayer graphene obtained by electrochemical exfoliation. The xray diffractogram of this material would resemble that of graphite, in that the 002 peak would still appear at 26 o 2 theta. Extrinsic wrinkling and single exfoliated sheets of graphene.
Graphene oxidesupported zinc oxide nanoparticles for. Hydrazinereduction of graphite and graphene oxide sungjin park a,b, jinho an a, jeffrey r. Graphite oxide can be exfoliated in solution to form monolayer graphene oxide or partially exfoliated to form fewlayer graphene oxide. Local current mapping of electrochemically exfoliated graphene oxide by conductive afm to cite this article. Preparation and characterization of exfoliated graphene oxide. Strong bonds link each carbon atom to three other carbon atoms and form hexagonal sixsided shapes. Exfoliated graphite oxide go sheets with hydroxyl groups and amine groups on the surface were prepared by modification of graphite. In this manner, graphene oxide as a substrate for graphenelike materials reduction process is getting more and more interesting. Pillaring chemically exfoliated graphene oxide with carbon. Structural, chemical, and morphological studies confirm the formation of egmno composite in which cubic mno crystallites are found to anchor onto eg surfaces. Then they were immobilized on glass carbon electrodes and their electrochemical behaviors for different charged. Complete oxidation of graphite for the formation of go is an.
Each layer of go is essentially an oxidized graphene sheet commonly referred to as graphene oxide. Although early routes to these materials were challenging, significant advances in synthetic and processing methods have enabled access to highquality exfoliated graphene oxide sheets in appreciable quantities. Multi or thick layer dispersions of graphene oxide exist more in graphite powder sample. The simplified hummers method provides a facile approach for the preparation of largearea exfoliated graphene oxide sheets. Surface charge research of graphene oxide, chemically reduced.
Preparation and characterization of graphene oxide paper. Nov 17, 2016 graphene is different in size and structure because of oxidized layered of graphene oxide hence, the expanded interlayer structure of graphene oxide can be easily exfoliated by ultrasonication. The abundant oxygencontaining functional groups on the surfaces of graphene oxide go play an important role in hgii. Note that the definitions proposed in the article will not necessarily take hold, and even if they do the transition will take some time. Preparation, fracture, and fatigue of exfoliated graphene.
The oxidation mechanism and chemical structure model of go were proposed by analyzing the evolution of the functional groupswith oxidation proceeded based onthermogravimetric. A facile and novel method for removal of hgii, based on the appealing interaction between exfoliated graphene oxide ego, lcystine, and hgii, is reported in this paper. In this contribution, the surface electrical properties of graphene oxide go, chemically reduced graphene oxide rgo and thermally exfoliated graphene oxide ego were characterized by zeta potential. Graphene oxide go, reduced graphene oxide rgo, exfoliated graphite nanoplatelets xgnp 1.
We understand that materials need optimization at every stage of development. Exfoliated graphene oxide egmoo2 composites are synthesized by a simple solidstate graphenothermal reduction method. Synthesis of graphene nano sheets by the rapid reduction of electrochemically exfoliated graphene oxide induced by microwaves article pdf available february 2016 with 3,890 reads how we. Graphite oxide with large lateral dimensions has an exfoliation yield of 100%, but it has not been possible to completely remove the oxygen functional groups so that the reduced form of graphene oxide go. At graphenea we are committed to the development of graphene materials from research to commercialization. This chapter details the synthesis and characterization of the exfoliated graphene oxide ego as well its suspensions in water. Graphene oxide go is used as a reducing agent to reduce moo3 and as a source for eg. Graphene oxide go, reduced graphene oxide rgo, exfoliated. For that purpose, both resistance measurements and investigation studies were carried out in order to characterize the.
Local current mapping of electrochemicallyexfoliated. Graphene oxides gos with large sheets and more perfect aromatic structure were prepared by a novel modified hummers method. We have found curious result that the number of graphene sheets in exfoliated graphene stack is dependent on the applied pressure for exfoliation of graphite oxide go. Pdf simple preparation of exfoliated graphene oxide sheets via. Electrochemically exfoliated graphene and graphene oxide for energy storage and electrochemistry applications dr. Sep 28, 2018 graphene oxide may be thermally or chemically reduced to yield reduced graphene oxide rgo nanosheets that retain some of their defects and oxygencontaining functional groups 17,18,19,20. Synthesis of graphenebased nanosheets via chemical. Thermally exfoliated graphene oxide tego used in this work has been produced by exposing graphite oxide obtained via brodie method to a quick thermal treatment at 1423 k in a quartz vial under dynamical vacuum. In different graphite forms two major absorbance peaks are observed. Moreover, go was chosen as the nanomaterial for the present study because it possesses interesting advantages compared to other materials, such as high. For exfoliated graphite, surfactant or organic solvent are used to exfoliate graphite to produce monofew layer graphene, whereas acid and oxidant are mixed with graphite to produce graphene oxide. Exfoliated graphene oxidemoo2 composites as anode materials. Preparation and characterization of exfoliated graphene.
Low yields of singlelayered graphene, submicrometer lateral dimensions, and poor electronic properties remain as major challenges for solution exfoliated graphene flakes 14. Sustainable graphenothermal reduction chemistry to obtain. Graphene is different in size and structure because of oxidized layered of graphene. Graphene has been produced by various methods and techniques from various precursors. Pdf simple preparation of exfoliated graphene oxide. Graphene oxide go and reduced graphene oxide rgo platelets were pillared with carbon nanotubes cnts by using the chemical vapor deposition cvd method with acetonitrile as the carbon source and nickel nanoparticles as the catalyst, aimed to prepare graphene based materials with a high surface area and a good electrical conductivity.
To make a concentrated aqueous dispersion that will not settle under gravity. Study of ultravioletvisible light absorbance of exfoliated. Graphene oxide quantum dots exfoliated from carbon fibers by. The significant attraction of these materials can be. Exfoliated graphene oxide egmoo 2 composites are synthesized by a simple solidstate graphenothermal reduction method. Graphene oxide quantum dots goqds attract great attention for their unique properties and promising application potential. The results assured that stirring in hot distilled water could give the product of graphene or reduced graphene oxide. We report on the preparation of exfoliated graphene oxide by using sonication method.
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