We produced carbon hybrid materials of graphene sheets decorated with metal or metal oxide nanoparticles of gold, silver, copper, cobalt, or nickel from cation exchanged graphite oxide. Measurements using powder X-ray diffraction, transmission electron microscopy, and X-ray absorption spectra revealed that the Au and Ag in the materials (Au-Gr and Ag-Gr) existed on graphene sheets as metal nanoparticles, whereas Cu and Co in the materials (Cu-Gr and Co-Gr) existed as a metal oxide. Most Ni particles in Ni-Gr were metal, but the surfaces of large particles were partly oxidized, producing a core-shell structure. The Ag-Gr sample showed a catalytic activity for the oxygen reduction reaction in 1.0 M KOH aq. under an oxygen atmosphere. Ag-Gr is superior as a cathode in alkaline fuel cells, which should not be disturbed by the methanol cross-over problem from the anode. We established an effective approach to prepare a series of graphene-nanoparticle composite materials using heat treatment ...
Highly oriented pyrolytic graphite (HOPG) is a highly pure and ordered form of synthetic graphite. It is characterised by a low mosaic spread angle, meaning that the individual graphite crystallites are well aligned with each other. The best HOPG samples have mosaic spreads of less than 1 degree. It is used in x-ray optics as a monochromator and in scanning probe microscopy as a substrate and for magnification calibration. Note that the term "highly ordered pyrolytic graphite" is sometimes used for this material, but IUPAC favors "highly oriented" The method used to produce HOPG is based on the process used to make pyrolytic graphite, but with additional tensile stress in the basal plane direction. This produces improved alignment of the graphite crystallites, and an interplanar spacing close to that observed in natural graphite. The "stress recrystallization" of graphite was first described by L.C.F. Blackman and Alfred Ubbelohde in 1962 The diameters of the individual crystallites in HOPG are ...
RS Mines proudly presents its Natural 99%+ Carbon, highly ordered pyrolytic graphite or highly oriented pyrolytic graphite (HOPG), 300g nuggets It is now understood and verified that a small percentage, ~3% of output from The Queens Mine is HOP G - Highly ordered pyrolytic graphite or highly oriented pyrolytic graphite (HOPG). The physical properties of HOPG - Highly Ordered Pyrolytic Graphite
Graphene is a carbon based material that can be viewed as a one atom thick sheet of graphite and has been investigated intensely in recent years following a report by Novoselov et al. on its isolation and measurement of its unique electronic properties.1 Quickly after its initial discovery, graphene was used to make electronic devices for a variety of applications.2 Because high quality sheets of graphene is often prepared by chemical vapor deposition (CVD),3,4 which requires expensive equipment, many groups have looked at using graphene oxide as a solution processable alternative for the preparation of graphene like materials.5,6,7 Indeed, graphene oxide can be reduced in solution and as a thin film using a variety of reducing conditions, and reduction converts the graphene oxide into a material that has a large enhancement in electrical conductivity.7,8 In addition to its use in making reduced graphene oxide for electronic devices, graphene oxide
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You can imagine that these microscale sheets may be stacked together and chemically linked, allowing us to further optimize the mechanical properties of the resulting macroscale object," Ruoff says. "This combination of excellent mechanical properties and chemical tunability should make graphene-based paper an exciting material.". Of further interest are the electrical properties of the graphene oxide paper in comparison to graphene sheets. "When we oxidize the graphene sheets to create graphene oxide, the material goes from being an electrical conductor to an electrical insulator," Ruoff says. "This is an important step and in the future it will be possible to tune the material as a conductor, semiconductor or insulator. One will be able to control the electrical properties without sacrificing exceptional mechanical properties.". Ruoff sees a wide variety of applications for graphene oxide paper, including membranes with controlled permeability, and for batteries or supercapacitors for energy ...
A solid state graphite electrode to determine the activity of an ion-specie in solution. The graphite electrode of the present invention can be adapted for use as either an external reference electrode, an ion-selective electrode or as an internal reference electrode. The electrode includes, as an electrically conductive element, a supported section of graphite that is appropriately electrically connected through a potentiometer to show a difference in ion concentration as a voltage potential or emf. One graphite surface for immersion in a test solution is hydrophobized by coating it with a solution that contains an organic liquid molecule to covalently bond with hydroxyl groups (OH) of the graphite surface, rendering that surface hydrophobic. Preferably, the organic liquid is a silanizing agent, which coating after drying is covered with a hydrophobic layer or membrane that is preferably a polyvinylchloride (PVC) plastic. For an ion-selective electrode, an ion sensor for the ion to be sensed is
We present a x-ray dichroism study of graphite surfaces that addresses the origin and magnitude of ferromagnetism in metal-free carbon. We find that, in addition to carbon {pi} states, also hydrogen-mediated electronic states exhibit a net spin polarization with significant magnetic remanence at room temperature. The observed magnetism is restricted to the top {approx}10 nm of the irradiated sample where the average magnetization reaches {approx_equal} 15 emu/g at room temperature. We prove that the ferromagnetism found in metal-free untreated graphite is intrinsic and has a similar origin as the one found in proton bombarded graphite. Also, our findings show that the magnetic properties of graphite surfaces, thin films or two dimensional graphene samples can be reliably studied using soft x-ray dichroism. Fundamental new insight into the magnetic properties of carbon based systems can thus be obtained.
Flake Graphite. Flake graphite is a naturally occurring form of graphite that is typically found as discrete flakes ranging in size from 50-800 micrometers in diameter and 1-150 micrometers thick. This form of graphite has a high degree of crystallinity, which equates to near theoretical true density, high thermal and electric conductivity, and low springback (excellent molding characteristics).. Flake graphite is used in many applications including but not limited to powder metallurgy, fuel cell bi-polar plates, coatings, thermal materials, friction moderators, electrically conductive materials, refractories, general lubricant applications, pencils, gaskets, rubber compounds, and other advanced polymer systems. Commercial grades are available in purities ranging from 80-99.9% carbon, and sizes from 2-800 microns.. An In-Depth Description - Flake Graphite. Request a Sample. Amorphous Graphite. Amorphous graphite is a naturally occurring seam mineral that forms from the geologic metamorphism of ...
Graphite Oxide, which is produced by Royal Elite in a Lab scale via a modified Hummers, has good solubility in water, ethanol, DMF etc. It is a new carbon material with good properties. Graphite Oxide can be easily dispersed in polar solvents with the help of ultrasound and it can be applied in many fields, such as preparation of graphene; conductive graphene film; biochemical materials; transparent conductive coatings; nano electro devices; sensor and optics; catalyst and energy storage.. PROPERTIES:. Purity: 99%. Stacking Density: 0.8~1g/ml. Color: Brown solid. C/O Ratio: 1.35. ...
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A variety of distinctive techniques have been developed to produce graphene sheets and their functionalized subsidiaries or composites. The production of graphene sheets by oxidative exfoliation of graphite can be a suitable route for the preparation of high volumes of graphene derivatives. P-substituted graphene material is developed for its application in hydrogen sorption in room temperature. Phosphorous doped graphene material with multi-layers of graphene shows a nearly ~2.2 wt% hydrogen sorption capacity at 298 K and 100 bar. This value is higher than that for reduced graphene oxide (RGO without phosphorous).
Graphite, which consists of layers of carbon atoms arranged in hexagonal lattices, can superconduct when doped with elements that provide it with additional free electrons. Calcium graphite, for example, superconducts at up to 11.5 kelvin (about -260 °C)2, and theorists have predicted that temperatures of up to 60 kelvin could be reached if enough free electrons were available.. Esquinazis team speculates that high concentrations of electrons form at the interfaces between neighbouring thin segments of graphite. Having already observed superconductivity at more than 100 kelvin at the interfaces within an artificial type of bulk graphite known as pyrolytic graphite3, the researchers wondered whether they could reach even higher temperatures by doping flakes of graphite powder.. The first dopant they tried was ordinary water. They got lucky. They placed 100 milligrams of pure graphite powder made up of flakes a few hundredths of a millimetre long and tens of nanometres thick into 20 millilitres ...
Magnetite, Fe3O4, is a promising anode material for lithium ion batteries due to its high theoretical capacity (924 mA h g−1), high density, low cost and low toxicity. However, its application as high capacity anodes is still hampered by poor cycling performance. To stabilize the cycling performance of Fe3O4 nanoparticles, composites comprising Fe3O4 nanoparticles and graphene sheets (GS) were fabricated. The Fe3O4/GS composite disks of mm dimensions were prepared by electrostatic self-assembly between negatively charged graphene oxide (GO) sheets and positively charged Fe3O4-APTMS [Fe3O4 grafted with (3-aminopropyl)trimethoxysilane (APTMS)] in an acidic solution (pH = 2) followed by in situ chemical reduction. Thus prepared Fe3O4/GS composite showed an excellent rate capability as well as much enhanced cycling stability compared with Fe3O4 electrode. The superior electrochemical responses of Fe3O4/GS composite disks assure the advantages of: (1) electrostatic self-assembly between high storage
Graphene1-3 possesses a unique application potential, such as in electronic devices,4,5 sensors6,7 and lithium ion batteries,8,9 owing to its remarkable electronic properties. The functionalization of pristine graphene by chemical and physical methods is crucial for broadening its application range by generating new properties.10 For instance, oxidized graphene or graphene oxide (GO) is more reactive than graphene11-15 and highly water-dispersible,16,17 making it a promising scaffold material for drug delivery,18 sensing,19,20 catalysis,21,22 imaging,23-25 substrates for implants26 and low-cost production of large quantities of graphene and graphene-based materials.27-29 GO is a structurally complex material whose nature depends on the oxidation method used.30 The surface of GO consists of randomly dispersed graphitic and oxidized regions covered by epoxy and hydroxyl groups. Other functional groups, such as carboxyl, quinone, ketone and peroxide, may also be present.12,31,32 Owing to its random ...
Large-Scale Pattern Growth of Graphene Films for Stretchable Transparent Electrodes." Nature 457, 706 (2009) Problems associated with large-scale pattern growth of graphene constitute one of themain obstacles to using thismaterial in device applications1. Recently, macroscopic-scale graphene films were prepared by two-dimensional assembly of graphene sheets chem-ically derived from graphite crystals and graphene oxides2,3 . However, the sheet resistance of these films was found to be much larger than theoretically expected values. Here we report the direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers, and present two differentmethods of patterning the films and transferring them to arbitrary substrates. The transferred graphene films show very low sheet resistance of 280Vper square, with 80 per cent optical transparency...... ...
Australian graphite stocks have experienced a veritable boost in the past few weeks as many more companies have joined the graphite industry in expectation of much higher demand for Lithium-ion batteries (which, despite their name, use more graphite than lithium). Including China, the graphite sector now includes eight countries and there are promising resources being developed in Canada, the USA, Madagascar, Sri Lanka and Sweden among others. Naturally, there are concerns - and justified ones - that nobody knows where the volume of graphite demand will be heading in the future. Indeed, the graphite market is not all that big now and caution is well, almost always useful. The bets are that those companies that can produce high levels of purity will have a huge competitive advantage and the market will surely weed out the number of graphite companies as the realities of establishing a solid customer base and delivering consistent high quality at low cost take over. The current purity standard for ...
University of Manchester scientists have studied membranes from a chemical derivative of graphene called graphene oxide. Graphene oxide is the same graphene sheet but it is randomly covered with other molecules such as hydroxyl groups OH-. Graphene oxide sheets stack on top of each other and form a laminate.. The researchers prepared such laminates that were hundreds times thinner than a human hair but remained strong, flexible and were easy to handle.. When a metal container was sealed with such a film, even the most sensitive equipment was unable to detect air or any other gas, including helium, to leak through.. It came as a complete surprise that, when the researchers tried the same with ordinary water, they found that it evaporates without noticing the graphene seal. Water molecules diffused through the graphene-oxide membranes with such a great speed that the evaporation rate was the same independently whether the container was sealed or completely open.. Dr Rahul Nair, who was leading the ...
Graphitic carbon is currently considered the state-of-the-art material for the negative electrode in lithium ion cells, mainly due to its high reversibility and low operating potential. However, carbon anodes exhibit mediocre charge/ discharge rate performance, which contributes to severe transport-induced surface structural damage upon prolonged cycling and limits the lifetime of the cell. Lithium bulk diffusion in graphitic carbon is not yet completely understood, partly due to the complexity of measuring bulk transport properties in finite-sized nonisotropic particles. To solve this problem for graphite, we use the DevanathanStachurski electrochemical methodology combined with ab initio computations to deconvolute and quantify the mechanism of lithium ion diffusion in highly oriented pyrolytic graphite (HOPG). The results reveal inherent high lithium ion diffusivity in the direction parallel to the graphene plane (∼10-7 -10-6 cm2 s -1 ), as compared to sluggish lithium ion transport along ...
One of the advantages of the gaphene oxide is its easy dispersability in water and other organic solvents, as well as in different matrixes, due to the presence of the oxygen functionalities. This remains as a very important property when mixing the material with ceramic or polymer matrixes when trying to improve their electrical and mechanical properties.. On the other hand, in terms of electrical conductivity, graphene oxide is often described as an electrical insulator, due to the disruption of its sp2 bonding networks. In order to recover the honeycomb hexagonal lattice, and with it the electrical conductivity, the reduction of the graphene oxide has to be achieved. It has to be taken into account that once most of the oxygen groups are removed, the reduced graphene oxide obtained is more difficult to disperse due to its tendency to create aggregates.. Functionalization of graphene oxide can fundamentally change graphene oxides properties. The resulting chemically modified graphenes could ...
TY - GEN. T1 - Evaluation of an affinity-amplified immunoassay of graphene oxide using surface plasmon resonance biosensors. AU - Chiu, Nan-Fu. AU - Huang, Teng Yi. AU - Kuo, Chun Chuan. PY - 2015/1/1. Y1 - 2015/1/1. N2 - We describe a fundamental study on the plasmonic properties and advanced biosensing mechanisms of functionalized graphene. We discuss a specific design using modified carboxyl groups, which can modulate surface plasmon (SP) coupling and provide an advantage for their binding to the sensing layer with high-performance affinity in an immunological reaction. The functionalized graphene-based surface plasmon resonance (SPR) biosensors have three advantages: high performance, high sensitivity, and excellent molecular kinetic response. In the future, functionalized graphene sheets will make a unique contribution to photonic and SPR diagnosis devices. We wish to highlight the essential characteristics of functionalized graphene-based SPR biosensors to assist researchers in developing ...
Interfacial interactions allow the electronic properties of graphene to be modified, as recently demonstrated by the appearance of satellite Dirac cones in graphene on hexagonal boron nitride substrates. Ongoing research strives to explore interfacial interactions with other materials to engineer targeted electronic properties. Here we show that with a tungsten disulfide (WS2) substrate, the strength of the spin-orbit interaction (SOI) in graphene is very strongly enhanced. The induced SOI leads to a pronounced low-temperature weak anti-localization effect and to a spin-relaxation time two to three orders of magnitude smaller than in graphene on conventional substrates. To interpret our findings we have performed first-principle electronic structure calculations, which confirm that carriers in graphene on WS2 experience a strong SOI and allow us to extract a spin-dependent low-energy effective Hamiltonian. Our analysis shows that the use of WS2 substrates opens a possible new route to access topological
A catalyst consisting of palladium - nickel supported on exfoliated graphene oxide (PdNi/EGO) composite was synthesized. The catalytic activity was tested for ethanol oxidation reaction (EOR) in half-cell using cyclic voltammetry (CV) and subsequently it was used as an anode material in a direct ethanol fuel cell (DEFC). Transmission Electron Microscopy showed the catalyst particles are uniformly dispersed on the surface of graphene oxide with the particle size ranging from 3 to 6 nm. X-ray Photoelectron Spectroscopy analysis of catalysts revealed that the surface consisting of mostly Pd, PdO, Ni(OH)2, and NiOOH. CV and chronoamperometry measurements demonstrated higher electrocatalytic activity and stability for PdNi/EGO in the alkaline medium than the unsupported PdNi and carbon black-supported PdNi (PdNi/C) catalysts. A single cell anion exchange membrane DEFC constructed with a PdNi/EGO anode catalyst showed a maximum power density of 16.6 m Wcm−2 at 50 °C, which is higher than the ...
Graphene nanoribbons (GNRs, also called nano-graphene ribbons or nano-graphite ribbons) are strips of graphene with width less than 50 nm. Graphene ribbons were introduced as a theoretical model by Mitsutaka Fujita and coauthors to examine the edge and nanoscale size effect in graphene. Large quantities of width-controlled GNRs can be produced via graphite nanotomy, where applying a sharp diamond knife on graphite produces graphite nanoblocks, which can then be exfoliated to produce GNRs. GNRs can also be produced by "unzipping" or axially cutting nanotubes. In one such method multi-walled carbon nanotubes were unzipped in solution by action of potassium permanganate and sulfuric acid. In another method GNRs were produced by plasma etching of nanotubes partly embedded in a polymer film. More recently, graphene nanoribbons were grown onto silicon carbide (SiC) substrates using ion implantation followed by vacuum or laser annealing. The latter technique allows any pattern to be written on SiC ...
This report reviews literature on reprocessing high temperature gas-cooled reactor graphite fuel components. A basic review of the various fuel components used in the pebble bed type reactors is provided along with a survey of synthesis methods for the fabrication of the fuel components. Several disposal options are considered for the graphite pebble fuel elements including the storage of intact pebbles, volume reduction by separating the graphite from fuel kernels, and complete processing of the pebbles for waste storage. Existing methods for graphite removal are presented and generally consist of mechanical separation techniques such as crushing and grinding chemical techniques through the use of acid digestion and oxidation. Potential methods for reprocessing the graphite pebbles include improvements to existing methods and novel technologies that have not previously been investigated for nuclear graphite waste applications. The best overall method will be dependent on the desired final waste ...
Graphite. False-colour scanning electron micrograph of scratches on the surface of a lubricating film of graphite. Graphite is a soft, slippery, crystalline form of carbon, widely used as a lubricant. It is applied to a surface in the form of an aqueous colloid (small particles of graphite suspended in water) & allowed to dry. The graphite forms a continuous sheet covering the surface & is gradually abraded as other parts rub against it. The lubricating nature of graphite is due to its molecular structure. The carbon atoms are arranged in arrays of flat hexagons, forming flakey plates (as seen here), which slip easily across each other. Mag: x300 at 35mm size. - Stock Image A150/0089
Ah, I see: I had compiled gcc-4.8.{0,1}* with graphite, of course. Maybe this is the reason for my many problems with graphite. On the other hand, it would be a strange accident that using gcc compiled with graphite just has problems for compiling with graphite. But who knows: Maybe the cause is that something in graphite is not reentrant or thread-safe and using graphite with a graphite-compiled gcc just forces such a behavior? ...
The unique two-dimensional (2D) structure and chemical properties of graphene and its derivatives make it a distinctive nanoscale building block for constructing novel bulky architectures with different dimensions, such as 1D fibers, 2D films and 3D architectures. These bulky graphene materials, depending on the manner in which graphene sheets are assembled, show a variety of fascinating features that cannot be achieved from individual graphene sheet or conventional materials. Thus, over the past several years, considerable effort has been expended in fabricating various structures of bulky graphene materials and developing their corresponding applications. Here, we present a broad and comprehensive overview of the recent developments in expanding the structural diversity of bulky graphene materials and their applications in energy storage and conversion, composites, environmental remediation, etc. Finally, prospects and further developments in this exciting field of bulky graphene materials are ...
Guanine adsorbed onto a highly oriented pyrolytic graphite electrode was studied by MAC-Mode Atomic Force Microscopy (AFM), and the electrochemical behaviour of the guanine layer was investigated with Electrochemical AFM. Guanine adsorbs spontaneously, without forming a well-packed structure, into nucleation spots, which are stable with time and cover the surface uniformly and almost completely. The process of guanine adsorption and nucleation can be controlled and the effect of altering the exposure time and varying the potential was investigated ...
Graphene has become one of the most widely studied 2D materials since its separation by Geim-Novoselov in 2004. It has been used in a wide range of applications due to its incredible carrier mobility, mechanical strength and thermal conductivity. The applications of graphene are ranging from electronics to energy storage and conversion. Chemical vapor deposition (CVD) is a common method for growing graphene on a metal surface as a catalyst, since it promotes growth of large area and high uniform graphene film. This requires an additional step to transfer graphene onto other target substrates toward fabrication of graphene-based devices. Graphene transfer process comprises many challenges such as presence of polymeric/metal residuals, generation of several extrinsic defects (tears, cracks and wrinkles) and weak adhesion between graphene and underlying target substrate. All these kinds of imperfections degrade graphene properties and hence affect the performance of the fabricated graphene-based ...
Exfoliation of pencil graphite core throughout electrolysis process is considered as one of the simple and friendly method to synthesis graphene from graphite. In this research, sodium sulphate (Na2SO4) was used as an electrolyte to investigate the effect on pencil graphite core with different grades for exfoliation process. Pencil graphite core was applied as both anode and cathode electrodes and exposed in 0.1 mol of Na2SO4 solution and followed with sonication in DMF solution. The morphology of exfoliated graphite was characterized by FESEM and TEM image. It was found that higher pencil grade produced more exfoliated powder as compared to lower grade pencil, and morphology investigation revealed that the exfoliated powder can produced graphene in nanoplatelet forms.. ...
成都阿泰克特种石墨有限公司是一家专业从事碳石墨产品加工制造的公司,且为德国西格里碳素集团(SGL CARBON GROUP)中国西南地区的总代理。采用从德国进口的优质碳素材料,我们为以下一些工业领域提供可靠的碳石墨产品:玻璃及石英工业用石墨、电火花放电加工用石墨电极、多晶及太阳能光伏、半导体及电子工业用石墨、机械用碳石墨、电工用碳石墨、有色及贵金属工业用石墨、真空电炉用石墨、按客户要求定做的其它碳石墨加工产品Chengdu ArTech Specialty Graphite Co.,Ltd. is a mid-sized factory which is specialized in carbon & graphite machining. We are the distributor on EDM graphite for SGL CARBON in south-west China. With imported high quality materials, we may supply reliable graphite parts for following fields: For Glass and Quartz Industry, Graphite Electrode for EDM, For Semiconductor and Electronics Industry, Mechanical Carbon, Electrical ...
Electronic spin transport properties of graphene nanoribbons (GNRs) are influenced by the presence of adatoms, adsorbates and edge functionalization. To improve the understanding of the factors that influence the spin properties of GNRs, local (element) spin-sensitive techniques such as electron spin resonance (ESR) spectroscopy are important for spintronics applications. Here, we present results of multi-frequency continuous wave (CW), pulse and hyperfine sublevel correlation (HYSCORE) ESR spectroscopy measurements performed on oxidatively unzipped graphene nanoribbons (GNRs), which were subsequently chemically converted (CCGNRs) with hydrazine. ESR spectra at 336 GHz reveal an isotropic ESR signal from the CCGNRs, of which the temperature dependence of its line width indicates the presence of localized unpaired electronic states. Upon functionalization of CCGNRs with 4-nitrobenzene diazonium tetrafluoroborate, the ESR signal is found to be 2 times narrower than that of pristine ribbons. NH{sub ...
The synthesis of graphite oxide (GrO) by oxidation of graphite has been carried out by different procedures. In this chapter, we describe a simple synthesis route based on Hummers method without the usage of NaNO3 achieving nearly the same outcomes, and this methodology is directed toward high-quality scale production of GrO with similar properties compared with GrO obtained with traditional and improved Hummers methods. The GrO was obtained in a series of batch reactions and characterized by different techniques, and the results showed identical interlayer d-space, type and content of oxygen functionalities, and ID/IG ratio. The high reproducibility of this methodology offers an efficient alternative for the large-scale production of graphene oxide.
Nanostructured graphitic carbons have widespread applications. However, the synthesis of such materials with a high surface area is still a great challenge. In this study, we demonstrate a new approach for improving the surface area. Graphitic carbon nanocages (CNCs) are prepared by spray pyrolysis of ethanol with dissolved iron carbonyl at high temperature. Ammonium thiocyanate is added to form iron sulfide as a less active catalyst and a template with less carbon dissolution and precipitation than single-phase Fe. This addition leads to an apparent reduction in cage size from 60 to 40 nm and wall thickness from 5-10 nm to 2-4 nm and a significant increase in surface area from 227 to 550 m2 g−1 at 800 °C. As an example of a potential application, the CNCs with a thin wall and high surface area are demonstrated to be a superb material for supporting the Pt catalyst used in low-temperature fuel cells. It is suggested that the present approach may be integrated with previous methods for ...
An electrolytic cell is provided that can include: a first electrode plate including a first surface that can include a graphite material; a second electrode plate including a second surface that can include a graphite material opposing the first surface; an electrolytic reaction zone between the first surface and the second surface; and an inlet to and an outlet from the electrolytic reaction zone. The first electrode plate and the second electrode plate can include resin-impregnated monolithic graphite plates. The first electrode plate and the second electrode plate can form opposite internal walls of a chamber for the electrolytic reaction and thus can be provided without a container for containing the electrode plates. Methods are also provided for flow-through-resin-impregnating porous, monolithic graphite plates to form electrode plates.
TY - JOUR. T1 - Direct and indirect electrochemical oxidation of amine-containing pharmaceuticals using graphite electrodes. AU - Liu, Yu Jung. AU - Hu, Ching Yao. AU - Lo, Shang Lien. PY - 2019/3/15. Y1 - 2019/3/15. N2 - This study investigated the direct and indirect electro-oxidation of amine-containing pharmaceuticals (acetaminophen (ACT), diclofenac (DIC), and sulfamethoxazole (SMX)) by using graphite electrodes, and to compare the influence by using different electrolytes (Na2SO4 and NaCl). Under the optimum conditions of current (I) at 0.5 A, in direct system, 74.3%, 90.0%, 81.6% of ACT, DIC, and SMX were respectively removed after 60 min (k = 0.023, 0.037, 0.027 min−1), 48.9%, 85.9%, 68.2% of TOC respectively removed after reaction time. In contrast, at the same current intensity, in indirect system, ACT, DIC, and SMX were eliminated within 30 min (k = 0.117, 0.307, 0.170 min−1), 89.6%, 92.6%, 99.6% of TOC respectively removed after reaction time. The results indicated that the ...
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Recent advances in on-body wearable medical apparatus and implantable devices drive the development of light-weight and bendable electrochemical sensors, which require the design of high-performance flexible electrode system. In this work, we reported a new type of freestanding and flexible electrode based on graphene paper (GP) supported 3D monolithic nanoporous gold (NPG) scaffold (NPG/GP), which was further modified by a layer of highly dense, well dispersed and ultrafine binary PtCo alloy nanoparticles via a facile and effective ultrasonic electrodeposition method. Our results demonstrated that benefited from the synergistic effect of the electrocatalytically active PtCo alloy nanoparticles, the large-active-area and highly conductive 3D NPG scaffold, and the mechanically strong and stable GP electrode substrate, the resultant PtCo alloy nanoparticles modified NPG/GP (PtCo/NPG/GP) exhibited high mechanical strength and good electrochemical sensing performances toward nonenzymatic detection of
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0269] 100: NMP, 101: graphene or RGO, 102: graphene oxide, 200: positive electrode, 201: positive electrode current collector, 202: positive electrode active material layer, 203: positive electrode active material particle, 204: graphene, 300: secondary battery, 301: positive electrode can, 302: negative electrode can, 303: gasket, 304: positive electrode, 305: positive electrode current collector, 306: positive electrode active material layer, 307: negative electrode, 308: negative electrode current collector, 309: negative electrode active material layer, 310: separator, 401: container, 402: graphene oxide dispersion liquid, 403: formation subject, 404: conductor, 405: container, 406: electrolyte solution, 407: conductor, 408: counter electrode, 500: secondary battery, 501: positive electrode current collector, 502: positive electrode active material layer, 503: positive electrode, 504: negative electrode current collector, 505: negative electrode active material layer, 506: negative ...
Can graphene be mixed and used to make products using product molds or presses?. As you may know, graphene can be acquired in two methods. 1) Top down: mechanically exfoliating carbon from graphite to make graphene powder or graphene oxide, 2) Bottom up: since carbon is composed of gas (ex. CH4, C2H4,,,) graphene film can be synthesized at high temperature through the CVD method. One of the options can be considered depending on the research goals. Due to graphenes characteristics, the theoretical prices and actual sample prices can vary and the characteristics of graphene powder and graphene film differ as well. As a result, when mixing graphene with other materials, graphene powder may be more appropriate. You would have to perform tests to find the right mixture ratios, but generally, mixing graphene powder with other materials to further manufacture products using molds or presses are possible. ...
Can graphene be mixed and used to make products using product molds or presses?. As you may know, graphene can be acquired in two methods. 1) Top down: mechanically exfoliating carbon from graphite to make graphene powder or graphene oxide, 2) Bottom up: since carbon is composed of gas (ex. CH4, C2H4,,,) graphene film can be synthesized at high temperature through the CVD method. One of the options can be considered depending on the research goals. Due to graphenes characteristics, the theoretical prices and actual sample prices can vary and the characteristics of graphene powder and graphene film differ as well. As a result, when mixing graphene with other materials, graphene powder may be more appropriate. You would have to perform tests to find the right mixture ratios, but generally, mixing graphene powder with other materials to further manufacture products using molds or presses are possible. ...
A pre-graphene paper exploring what graphite oxide actually looks like. The authors make graphite oxide from Hummers method (KMnO4/H2SO4), then fool about with it by pumping it full of things like water, KI, thiourea, NaOH, NaOEt, dioxane, DMSO, and a number of other compounds. They then used a fancy diffraction measurement called a Debey-Sherrer photograph to determine interlayer distances and 13C and 1H magic angle spinning (MAS) NMR to determine structure. They found that water is an intricate part of graphite oxide, and that most of the oxygen that is covalently bound to graphite oxide is in the form of alcohols and epoxides. Although this isnt in the paper, I believe that most of the defects in graphene formed from this method come from the epoxide centers, not the hydroxide centers. The original paper also found that, instead of oxidation happening uniformly over the area of the graphite, there are oxidation-heavy regions and then regions where hardly anything is oxidized ...
A pre-graphene paper exploring what graphite oxide actually looks like. The authors make graphite oxide from Hummers method (KMnO4/H2SO4), then fool about with it by pumping it full of things like water, KI, thiourea, NaOH, NaOEt, dioxane, DMSO, and a number of other compounds. They then used a fancy diffraction measurement called a Debey-Sherrer photograph to determine interlayer distances and 13C and 1H magic angle spinning (MAS) NMR to determine structure. They found that water is an intricate part of graphite oxide, and that most of the oxygen that is covalently bound to graphite oxide is in the form of alcohols and epoxides. Although this isnt in the paper, I believe that most of the defects in graphene formed from this method come from the epoxide centers, not the hydroxide centers. The original paper also found that, instead of oxidation happening uniformly over the area of the graphite, there are oxidation-heavy regions and then regions where hardly anything is oxidized ...
Page contains details about poly(dimethylsiloxane)/graphene/graphene oxide/reduced graphene oxide film . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com
Graphene-based nanocomposites have received huge attention in many areas of science and engineering because the nanoscale dispersion of graphene enhances many properties including mechanical, thermal, and morphological behavior compared with the pure polymers or conventional composites. Polybenzoxazines are a versatile class of thermosetting polymers that possess many desirable physical properties. To the best of our knowledge, the properties of polybenzoxazine nanocomposite aerogels containing graphene oxide have not yet been investigated. Herein we report graphene-based nanocomposite aerogels of polybenzoxazine, which are prepared via freeze-drying. The preparation of graphene oxide was confirmed using Raman spectroscopy and Fourier transform infrared (FTIR). Benzoxazine precursors were synthesized using 4-hydroxybenzaldehyde as phenolic component, paraformaldehyde, and two different functional polyetheramines. The chemical structures of the benzoxazine precursors were confirmed by nuclear ...
ABSTRACT: Graphene quantum dots (GQDs), which are atomically-thin and nanometer-wide planar carbon structures, are the most recent addition to the nanocarbon materials family. These emerging 0D materials promise a wide range of novel applications. In contrast to zero-gap 2D graphene sheets, 0D GQDs fluoresce due to quantum confinement induced bandgap opening. Also as compared to 2D graphene sheets, 0D GQDs are high dispersible; have larger fraction of edge sites; and can be more drastically tuned in chemiophysical properties through conjugation with various chemical groups, doping with heteroatoms, hybridization with other functional nanomaterials. In this presentation, we demonstrate strategies to engineering GQD bandgap, application of GQDs for bioimaging, sensing, and catalysis. Various methods to synthesize and modify GQDs will be described in conjunction with the application examples. BIOGRAPHY: After receiving b​achelors and Masters degrees from Zhejiang University (China), Dr Peng ...
Graphene oxide membranes were recently suggested for applications in separation of ethanol from water using a vapor permeation method. Using isotope contrast, neutron reflectivity was applied to evaluate the amounts of solvents intercalated into a membrane from pure and binary vapors and to evaluate the selectivity of the membrane permeation. Particularly, the effect of D2O, ethanol and D2O-ethanol vapours on graphene oxide (GO) thin films (similar to 25 nm) was studied. The interlayer spacing of GO and the amount of intercalated solvents were evaluated simultaneously as a function of vapour exposure duration. The significant difference in neutron scattering length density between D2O and ethanol allows distinguishing insertion of each component of the binary mixture into the GO structure. The amount of intercalated solvent at saturation corresponds to 1.4 molecules per formula unit for pure D2O (similar to 1.4 monolayers) and 0.45 molecules per formula unit (one monolayer) for pure ethanol. ...
The growing demand on graphene oxide raises substantial questions regarding environmental concerns. A group led by Ren Wencai at the Institute of Metal Research of the Chinese Academy of Sciences developed a green and fast method which allows to produce graphene oxide on large scales.
Synthesis of Graphene Oxide GO by Modified Hummers Method and Its Thermal Reduction to Obtain Reduced Graphene Oxide rGO*. . Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.
The idea depends on prepared quantum dots semiconductor nanoparticles of a highly stable cesium-lead halide perovskite, as well as a composite material made of these quantum dots and graphene oxide. Both materials showed an efficient absorption of visible light and strong luminescence. The leader of team Dai-Bin Kuang and colleagues used these products to achieve a fundamental step in artificial photosynthesis the reduction of CO2. To simulate sunlight, they used a xenon lamp with an appropriate filter.. Perovskite quantum dot photocatalysts surpassed the efficiency of cadmium sulfide and other state-of-the-art materials in the conversion of CO2 to carbon monoxide and methane. Chemists also demonstrated the synergetic effect of the composite - when combined with graphene oxide, perovskite Quantum Dots (QDs) achieved photocatalytic performances 26% higher than QDs alone. According to researchers, graphene oxide boosts the efficiency of the QDs improving the charge separation and transportation. ...
BUFFALO, N.Y. - Its not X-ray vision, but you could call it infrared vision.. A University at Buffalo-led research team has developed a technique for "seeing through" a stack of graphene sheets to identify and describe the electronic properties of each individual sheet - even when the sheets are covering each other up.. The method involves shooting a beam of infrared light at the stack, and measuring how the light waves direction of oscillation changes as it bounces off the layers within.. To explain further: When a magnetic field is applied and increased, different types of graphene alter the direction of oscillation, or polarization, in different ways. A graphene layer stacked neatly on top of another will have a different effect on polarization than a graphene layer that is messily stacked.. "By measuring the polarization of reflected light from graphene in a magnetic field and using new analysis techniques, we have developed an ultrasensitive fingerprinting tool that is capable of ...
This is an Irish Geological Association Lecture presented by George Reynolds (Metric Consulting).. Abstract: Graphite has been known from antiquity as a material for marking and writing. Although graphite has always been thought of as a low-value product it is a vital element in nuclear technology, electrical components and steel-making. Graphites nano-thin relative, graphene, is making its own mark in a range of high-tech and green technologies, such as solar cells and computer touch screens. Graphite itself is an essential part of the rechargeable batteries needed by mobile phones and laptops and, crucially, the batteries needed for electric and hybrid vehicles. The European Union has recently declared graphite a critical material. Commercial deposits are rare, but exploration methods are very effective. Ireland itself has some graphite-bearing rocks ... and perhaps the GSIs Tellus survey will discover more! ...
This thesis examines possible routes for the preparation of graphene nanostructures on metal substrates and performs structural and electronic characterizations using scanning tunneling microcopy and spectroscopy. Investigations of graphene nanostructures necessitate the use of a suitable graphene-substrate combination, which allows for a controlled in situ preparation of small and well-shaped graphene nanostructures. The choice of a graphene-substrate combination with weak interaction in order to prevent the destruction of monolayer graphene properties is inevitable.,br /,,br /,Within this work graphene layers and graphene nanostructures are grown using well-established procedures based on thermal decomposition of hydrocarbons on Ir(111) and Rh(111) surfaces. Implementing intercalation - the insertion of additional material between graphene and substrate - allows for a tailoring of interactions between graphene and the substrate. In the first part of this work the intercalation of Fe and Ni is ...
Graphene has excellent mechanical, thermal, optical and electrical properties and this has made it a prime target for use as a filler material in the development of multifunctional polymeric composites. However, several challenges need to be overcome to take full advantage of the aforementioned properties of graphene. These include achieving good dispersion and interfacial properties between the graphene filler and the polymeric matrix. In the present work, we report the thermal and mechanical properties of reduced graphene oxide/epoxy composites prepared via a facile, scalable and commercially viable method. Electron micrographs of the composites demonstrate that the reduced graphene oxide (rGO) is well dispersed throughout the composite. Although no improvements in glass transition temperature, tensile strength and thermal stability in air of the composites were observed, good improvements in thermal conductivity (about 36 %), tensile and storage moduli (more than 13 %) were recorded with the ...
A simple, low-cost and eco-friendly method of creating nitrogen-doped graphene nanoplatelets (NGnPs), which could be used in dye-sensitized solar cells and fuel cells.
The successful exfoliation of graphite initiated new science in any research field and is employing a huge number of scientists in the world investigating chemical, structural, mechanical and optoelectrical; properties of the atomic-thick sheets of graphene and graphene oxide. Similarly to other carbon-based materials, graphene family have shown exceptional optical responses; and nowadays it is engineered to produce efficient photonic components. In this review we aim to summarize the main results in nonlinear optical response and fluorescence of graphene oxide; moreover, its laser printing is reviewed as a novel promising lithographic technique. Neda Ghofraniha and Claudio Conti in Journal of Optics ...
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Make your WR8 light and lean with these performance-oriented woven graphite option parts! Replacing the stock aluminium center bulkead brace with this woven graphite option is a great way to customize the look of your WR8 3.0. Youll also lighten the weight of your car as well as increase its overall rigidity, giving you extra performance and an edge on the competition.. Please note: Will only fit the Bullet 3.0 if using smaller spur gear.. Use the complete range of woven graphite parts for your WR8 Flux to make it a race-ready rally car! #109010 CENTER BULKHEAD BRACE (WOVEN GRAPHITE/2MM/WR8 ...
Strategic Energy Resources (SER) is one stock with exposure to Graphite through its Uley project in South Australia. The company through former management and under a different name have had Uley project for some time however due to low prices for graphite the project has been under care and maintenance since 1993. This is about to change. Demand for graphite is increasing and the mineral has been noted as one of 14 by the European Union as critical as a result of it only being produced by a small amount of countries. China produces 80% of the worlds graphite and recently introduced taxes to curb export of the mineral. Sound familiar to rare earths ...
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Posted by Darryl Stevens on Jun 14, 2006. Jeff -- I used the wide blue masking tape with no problems. The graphite/epoxy is not as thin as straight epoxy so you wont have a problem. Plan on re-masking after each coat and be sure to remove it within 1-2 hrs or you may never get it off. I did the the graphite/epoxy before I varnished the boat as I didnt want to take a chance with any tape residue on the varnish. Sand between coats, but lightly until you have the 3rd coat down, and watch the corners or you will be adding another 3 coats on these. The graphite/epoxy hull will be a lot easier to maintain than a all varnished boat.. In Response to: Graphite epoxy for hull by jeffrey wong on Jun 14, 2006. ...
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Mason Graphite Inc operates in the Miscellaneous Nonmetallic Minerals sector. Mason Graphite Inc. is a Canada-based exploration-stage company. The Company is engaged in exploration and evaluation of the Lac Gueret graphite property located in Quebec, Canada. The Companys Lac Gueret graphite property consists of approximately 215 claims covering an area of approximately 11,630.34 hectares, located in the Cote-Nord region in northeastern Quebec. The Lac Gueret deposit is located approximately 285 kilometers north of Baie-Comeau and over 660 kilometers from Montreal. The Lac Gueret property is in the exploration and evaluation-stage.
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The researchers then set out to test the efficiency of the hydrogel, and see how it affected the growth of three different organisms - Staphylococcus aureus, Escherichia coli (gram-positive and gram-negative bacteria, respectively), and the fungus Candida albicans. To check this, they grew the organisms on four types of surface: plain agar, agar shaped to mimic the crabs carapace, agar with embedded graphene oxide and the agar hydrogel itself.. They found that both the agar shaped to resemble the carapace and the agar containing graphene oxide reduced the growth of all organisms by about 10% as compared to the plain agar. But when the agar was both shaped to mimic the carapace and contained graphene oxide, this reduction of growth was much more prominent. The growth of S. aureus was reduced by as much as 53%, E. coli by 40% and C. albicans by 30%.. The colonies of the organisms that were able to grow were also significantly smaller on the agar hydrogel, with S. aureus colonies reduced by 70%, ...
Researchers from King Abdullah University of Science and Technology (KAUST), in collaboration with the Georgia Institute of Technology, have recently demonstrated a simple, solution-based, method for surface doping of few-layer graphene (FLG) using novel dopants (metal-organic molecules) that show a minimal effect on the optical transmission as compared to other dopants like metal chlorides.. This work investigates the effect of dopant strength and dosage on the electronic and electrical transport properties of doped FLG. Moreover, It reveals fundamental differences between the doping results in single layer graphene and few-layer graphene. The study focused on few-layer CVD graphene, rather than single-layer CVD graphene, a somewhat less common area of research to date.. ...
The present thesis is focused on various methods of controlling electronic and geometrical structure of two-dimensional overlayers adsorbed on metal surfaces exemplified by graphene and hexagonal boron nitride (h-BN) grown on transition metal (TM) substrates. Combining synchrotron-radiation-based spectroscopic and various microscopic techniques with in situ sample preparation, we are able to trace the evolution of overlayer electronic and geometrical properties in overlayer/substrate systems, as well as changes of interfacial interaction in the latter.It is shown that hydrogen uptake by graphene/TM substrate strongly depends on the interfacial interaction between substrate and graphene, and on the geometrical structure of graphene. An energy gap opening in the electronic structure of graphene on TM substrates upon patterned adsorption of atomic species is demonstrated for the case of atomic oxygen adsorption on graphene/TMs (≥0.35 eV for graphene/Ir(111)). A non-uniform character of ...
A novel 3D nanostructure consisting of Ni(OH)2 nanoparticles, carbon nanotubes (CNTs), and reduced graphene oxide with an extremely high electrocapacitance is described. The nanostructure consists of CNTs with embedded Ni(OH)2 nanoparticles as pillars for reduced graphene oxide sheets. Electrochemical results show that the composite displays specific capacitances as high as 1235 and 780 F g-1 at current densities of 1 and of 20 A g-1, respectively. In addition, the composite retains 80% of its original capacity after 500 cycles at a discharge current density of 10 A g-1. This 3D pseudocapacitor electrode has a number of important features, such as fast ion and electron transfer, easy access ofpseudoactive species and efficient utilization, and excellent reversibility of Ni(OH) 2 nanoparticles. © 2012 Elsevier B.V. All rights reserved ...
This thesis begins with revisiting the precursor phase of graphene i.e. 6H-SiC(0001)-(6sqrt3x6sqrt3)R30° (hereafter 6sqrt3 for short), followed by probing the graphitisation mechanism adopted by 6H-SiC(0001) and adsorption studies of Co at both room and elevated temperatures. Scanning tunneling microscopy (STM) and photoelectron spectroscopy were used as main characterisation tools. Beginning with the 6sqrt3 phase, considerable amount of Si are found to exist on this surface. Their presence may be the reason the carbon-rich 6sqrt3 is refrained from directly converting to graphene. The graphene growth is found to begin from step edges with simultaneous collapse of the 6sqrt3 surface and three silicon carbide (SiC) bilayers underneath where the later disintegrated into a fresh 6sqrt3-like layer at the interface. This interface acts as a buffer to graphene from direct interaction with bulk SiC. For multilayer graphene formation, the same mechanism repeats again for each monolayer formed. In ...
We study the interaction of H-2 , O-2 , CO, H-2 O and OH molecules with the vacancy defects of graphene and silicene. Atoms around the bare vacancy reconstruct and specific chemically active sites are created. While H-2 , O-2 and CO remain intact on both pristine graphene and silicene, these molecules can dissociate when they are placed at the close proximity of these chemically active sites and nucleate centers for the hydrogenation and oxygenation. Saturation of the dangling bonds at the defect sites by constituent atoms of dissociated molecules gives rise to significant modification of electronic and magnetic properties. We analyzed the mechanism of the dissociation and revealed a concerted action of surrounding host atoms together with dissociated molecules to lower the energy barrier needed for dissociation. The dissociations of H-2 O and OH are hindered by high energy barriers. Our study suggests that graphene and silicene can be functionalized by creating meshes of single vacancy, where ...
0031]FIG. 3 shows a device that may be fabricated by employing the FIG. 1 process, or by the variant of this process, partly depicted in FIG. 2. The device 31 comprises a power supply 32, a first graphene electrode 17, and a second graphene electrode 18. The device further comprises a graphene semiconductor 15, which is between, and in electrical contact with, the first and second graphene electrodes 17, 18. It has been shown that when graphene is confined to nanoribbons it changes from semi-metallic to semiconducting material, the graphene semiconductor 15 therefore comprises such nanoribbons. A potential difference is applied between a first point 37, in the first graphene electrode 17, and a second point 38, in the second graphene electrode 18, and an electric current is passed through the graphene semiconductor 15, between the first and second points 37, 38, such that a potential difference is established between the first and second points, and such that there is substantially no potential ...
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Nitrogen-doped reduced graphene oxide (N-doped RGO) samples with a high level of doping, up to 13 wt. %, have been prepared by annealing graphene oxide under a flow of pure ammonia. The presence of nitrogen within the structure of RGO induces a remarkable increase in the thermal stability against oxidation by air. The thermal stability is closely related with the temperature of synthesis and the nitrogen content. The combustion reaction of nitrogen in different coordination environments (pyridinic, pyrrolic, and graphitic) is analyzed against a graphene fragment (undoped) from a thermodynamic point of view. In agreement with the experimental observations, the combustion of undoped graphene turns out to be more spontaneous than when nitrogen atoms are present.. ...
Buckytubes: computer graphics representation of a group of graphitic carbon microtubules, of various lengths. These needles of carbon were discovered in the soot on the carbon electrodes used to synthesise fullerenes, the best-known of which is C60, Buckminsterfullerene. Within each individual sheet, the carbon molecules are arranged in a helical structure. Fullerene tubes may possess an extraordinary diversity of properties, from the strength of carbon fibres to the electronic nature of graphite. The giant fullerenes, C240 for example, may have buckytubes incorporated into their structures. - Stock Image A700/0047
Combined neutron and X-ray diffraction has been used to structurally characterize the crystalline monolayer structures of fluoroalkane monolayers, C6 to C16, adsorbed on graphite at submonolayer coverages and over the temperature range from 10 K until the layers melt. In all cases the molecules are found to have their carbon backbones parallel to the graphite surface, although the experimentally determined patterns are not particularly sensitive to the orientation of the fluoroalkanes about their long axis on the surface. The layers appear to be incommensurate with the underlying substrate. A significant number of the fluoroalkanes also exhibit both a high and a low temperature phase, attributed to the onset of a rotator phase at higher temperatures. Interestingly, the temperature range of the high temperature phase is much greater than found for the alkanes. The scattering cannot distinguish the chirality of these helical molecules on the surface.. ...
Highly Exfoliated Graphite Fluoride as a Precursor for Graphene Fluoride Dispersions and Films. . Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.
The same technology that has been used to strengthen polymers1, de-ice helicopter wings2, and create more efficient batteries3 may one day help those with damaged or even severed spinal cords walk again. The Tour Lab at Rice University, headed by Dr. James Tour, is harnessing the power of graphene nanoribbons to create a special new material called Texas-PEG that may revolutionize the way we treat spinal cord injuries; one day, it may even make whole body transplants a reality.. Dr. Tour, the T.T. and W.F. Chao Professor of Chemistry, Professor of Materials Science and NanoEngineering, and Professor of Computer Science at Rice University, is a synthetic organic chemist who mainly focuses on nanotechnology. He currently holds over 120 patents and has published over 600 papers, and was inducted into the National Academy of Inventors in 2015.4 His lab is currently working on several different projects, such as investigating various applications of graphene, creating and testing nanomachines, and ...
Page contains details about platinum nanoparticles loaded graphitic carbon nitride nanosheets based electrode material . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com
Australian researchers say the filtering properties of the sand are considerably enhanced when it is coated with a nanomaterial called graphite oxide (GO).
In this article, graphene is investigated with respect to its electronic properties when introduced into field effect devices ( FED). With the exception of manual graphene deposition, conventional top-down CMOS-compatible processes are applied. Few and monolayer graphene sheets are characterized by scanning electron microscopy, atomic force microscopy and Raman spectroscopy. The electrical properties of monolayer graphene sandwiched between two silicon dioxide films are studied. Carrier mobilities in graphene pseudo-MOS structures are compared to those obtained from double-gated Graphene-FEDs and silicon metal-oxide-semiconductor field-effect-transistors ( MOSFETs).. ...
Graphene oxide (GO) is modified using the Johnson-Claisen rearrangement, an improvement over the groups previously reported GO functionalization methods. By utilizing triethyl orthoacetate (TEOA) as reagent and solvent, the rearrangement installs carbon bonded reactive ester functionalities that are not affected by further reduction of the GO to its more conductive counterpart, Graphene. The ester-functionalized GO was then reduced using sodium borohydride. After reduction, treatment with oxalyl chloride and subsequent reaction with various amines creates amide functionalized graphenes with various properties. By installing propargyl groups, they make a "clickable" graphene surface. Furthermore, by using a sulfonated azide tag, they are able to assess the degree of functionalization by XPS. In an alternate demonstration of the use of their method, they synthesize cationic and anionic graphene derivatives and assemble them in a layer by layer fashion to create graphene sheets up to 12 layers ...
Carbon sorbents The new generation of carbon-based materials has found application in many branches of science, including separation science. Carbon nanotubes and fullerenes, and some functionalised forms with added chemical groups, have found a growing number of uses in the extraction of compounds like drugs and pollutants. A further carbon form...
Since their discovery in 1991, carbon nanotubes (CNTs) have stimulated a great deal of research aimed at elucidating their properties as well as defining new applications in diverse fields. CNTs are allotropes of carbon and they can be described as a rolled up graphene sheet in which the carbon atoms are found in the sp2 conformation. Depending on the number of graphene sheets concentrically rolled up to form the tubes, these are classified as single-wall nanotubes (SWNTs) or multi-wall nanotubes (MWNTs). CNTs present distinctive properties that have drawn the attention of scientists interested in the development of novel biomaterials for pharmaceutical and medical applications. In particular, their ability to penetrate cell membranes by virtue of their needle like structure makes them of great interest for drug delivery applications. A few issues regarding CNTs have been challenging researchers in the biomedical field, namely low solubility, toxicity and biopersistance. We have recently ...
Graphene is a sheet of carbon that is only one atom thick, and it has drawn worldwide attention as a new material. A research group from Kumamoto University, Japan has discovered that pressure can be generated by simply stacking ...
Several transition metals other than the largely used Cu and Ni can be, in principle, employed to catalyze carbon precursors for the chemical vapor deposition of graphene, because the thermodynamics of their alloying with carbon is well known. For example, the wealth of information in the Co-C phase diagram can be used to predict the properties of graphene grown in this way. It is, in fact, expected that growth occurs at a temperature higher than in Ni, with beneficial consequences to the mechanical and electronic properties of the final product. In this work, the growth of graphene onto Co film is presented together with an extensive Raman characterization of the structural properties of the material so far obtained. Previous results reporting the full coverage with negligible defective areas, in spite of discontinuities in the underlying metal, are confirmed, together with the occurrence of strain in the graphene sheet. Strain is deeply investigated in this work, in view of possible employment in
TY - JOUR. T1 - TiO2-reduced graphene oxide nanocomposites by microwave-assisted forced hydrolysis as excellent insertion anode for Li-ion battery and capacitor. AU - Kim, Hyun Kyung. AU - Mhamane, Dattakumar. AU - Kim, Myeong Seong. AU - Roh, Ha Kyung. AU - Aravindan, Vanchiappan. AU - Madhavi, Srinivasan. AU - Roh, Kwang Chul. AU - Kim, Kwang Bum. PY - 2016/9/30. Y1 - 2016/9/30. N2 - TiO2-reduced graphene oxide (rGO) nanocomposite (TiO2-rGO) is fabricated by microwave-assisted forced hydrolysis and examined as prospective electrode for energy storage applications, especially in Li-ion battery (LIB) and Li-ion capacitor (LIC). First, the uniformly distributed nanoscopic TiO2 particulates (∼3 nm) over rGO nanosheets is evaluated as anode in half-cell assembly to ascertain the Li-insertion behavior and found that ∼0.68 mol Li (∼227 mAh g−1) is reversible. Then, "rocking-chair" type LIB is fabricated with spinel LiMn2O4 cathode, and the LiMn2O4/TiO2-rGO assembly exhibits high capacity ...
But, as with rare earths, being a graphite play means a lot more than just becoming a miner. There is a technology wall to climb, and few have begun that climb.. In this interview with InvestorIntels Fred Cowans, Northern Graphite CEO Gregory Bowes explains the technology leap that faces most juniors. Using Freds opening example of a cell phone battery that died after just three years, Gregory Bowes then goes on to explain the leap in technology required from producing batteries for cameras and cell phones (that would usually be replaced before three years was up) to those for electric vehicles where such cars need to retain 80% of their battery capacity after eight years.. As he explains:. ...
p,In this study, we calculated the diffusion of an Fe atom on graphene and various light-element (B, N, O, Si, P, and S)-doped graphene supports, using first-principles calculations based on density functional theory. We focused on dopants that could suppress the detachment and diffusion of an Fe atom. Such doped graphene supports would have strong potential in high-durability fuel cell catalysts and hydrogen storage materials. The Fe atom adsorbs on pristine graphene via ionic bonding. The bonding between the Fe atom and pristine graphene is very weak, and it has a low adsorption energy of −0.61 eV. Doped graphene contains unoccupied localized orbitals. B-, O-, Si-, and P-doped graphene show high adsorption energies of −1.70 eV, −2.70 eV, −1.46 eV, and −1.38 eV, respectively. Thus, these graphene supports could suppress the detachment of Fe nanoclusters and nanoparticles. We demonstrate that these doped graphene supports with high adsorption energies also have high diffusion barriers, ...
0004 - "Metal-Free Stabilizers for PVC" (Issued U.S. Patent Nos. 6,667,357; 6,747,081; 6,762,231; 6,927,247). 0506 - "Smoke and Fire Inhibitors for PVC" (Issued U.S. Patent No. 7,718,725). 0507 - "Method for the Synthesis of Graft Copolymers from Polymers of Vinyl Chloride" (Issued U.S. Patent No. 7,339,004). 0608 - "Organic Thiol Stabilizers and Plasticizers for Halogen-Containing Polymers" (Issued U.S. Patent No. 7,553,897). 0911 - "Method for Making Polymer Composites Containing Graphene Sheets" (Issued U.S. Patent No. 9,162,896). 1207 - "Synthesis of [2.2.2]-Diazabicyclic Ring Systems" (Issued U.S. Patent No. 8,796,454). 1407 - "Polyamide Composites Containing Graphene Sheets" ...
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Fuel cells are clean, compact and modular energy generation devices that generate electricity by a chemical reaction between a fuel and an oxidant. Polymer electrolyte membrane fuel cell (PEMFC) offers several advantages for both mobile and stationary applications yet it is necessary to develop low cost and more efficient PEMFCs. The heart of the PEMFC is the membrane electrode assembly composed of a proton exchange membrane sandwiched between two porous gas diffusion electrodes. At this point, graphene is a promising candidate as catalyst support material for PEMFCs due to its outstanding mechanical, structural, and electronic properties. Herein, the support material becomes significant to get high catalytic performance of catalysts by lower catalyst loadings. For the production of advanced type of gas diffusion layers, the distinguished properties of graphene are combined with the structural properties of conducting polymers and the impregnation of low-amount of Pt catalysts on graphene ...
Optimization of Current-Voltage Characteristics of Graphene-Based Biosensors: 10.4018/978-1-5225-0736-9.ch010: The aim of this project is to study and develop graphene-based DNA sensor model for detection of DNA hybridization application. This includes modeling and
Chemical vapor deposition on copper is the most widely used method to synthesize graphene at large scale. However, the clear understanding of the fundamental mechanisms that govern this synthesis is lacking. Using a vertical-flow, cold-wall reactor with short gas residence time we observe the early growths to study the kinetics of chemical vapor deposition of graphene on copper foils and demonstrate uniform synthesis at wafer scale. Our results indicate that the growth is limited by the catalytic dissociative dehydrogenation on the surface and copper sublimation hinders the graphene growth. We report an activation energy of 3.1 eV for ethylene-based graphene synthesis. © The Electrochemical Society.. ...
Graphene is a mono-layer carbon material with low cost, high chemical/thermal stability, and ultrahigh strength and is expected to be a replacement of silicon and noble metals for electron devices, battery materials, photo-/ion detectors and catalysts. Although some of graphene products such as display and electrodes are commercially available, the applications are limited due to the 2D sheet structure. In other words, the performance per gram is excellent but the performance per volume cannot be achieved easily. Therefore, many efforts have been made to construct the 2D material as a 3D structure with retained physical/chemical properties and high volumetric performance. However, the reported 3D nanoporous carbon materials suffer from poor mobility because of the lower crystallinity, which cannot be used for the electron devices. To achieve semiconductor-grade 3D carbon materials, the monolayer graphene sheet with a high crystalline structure is required in a 3D structure. Thus, we have ...
The bottom-up fabrication of graphene nanoribbons (GNRs) has opened new opportunities to specifically tune their electronic and optical properties by precisely controlling their atomic structure. Here, we address excitation in GNRs with periodic structural wiggles, the so-called chevron GNRs. Based on reflec
With the rise of graphene research since 2004, the past few years have witnessed rapid progreess in exploiting graphene as an electronic material that shows great promise for future nano-electronic devices. Particular interest in this regard stems from the remarkable electronic properties of graphene, ranging from the extremely high mobility to the tunable carrier type and density. However, the fact that graphene is a zero-bandgap semimetal poses a major problem for its practical applications in making high-performance ï¬ eld-effect transistors (FETs). As to how an energy gap can be induced in graphene, a known paradigm is to fabricate 1D ultranarrow graphene nanoribbons (GNRs) in which the lateral conï¬ nement of charge carriers cre-ates an energy gap near the charge neutrality point. Experi-mentally, ultranarrow GNRs were ï¬ rst fabricated by standard electron beam lithography (EBL) patterning in combination with reactive O 2 plasma etching of graphene sheets; how-ever EBL is known to be ...