New Form Of Carbon Research Articles

Features of the synthesis of fullerenes and their derivatives

The discovery of a new form of carbon was the great scientific breakthrough of the 20th century. Carbon is one of the most abundant elements on our planet. A molecule consisting of 60 carbon atoms was named a fullerene. Fullerene C60 is a molecule consisting of 20 hexagonal and 12 pentagonal rings with carbon atoms at their vertices, and has a high symmetry. The radius of C60 fullerene is 0.3512 nm, the length of the short bond separating the hexagons is 0.1391 nm, and the length of the long bond common to hexagons and pentagons is 0.1455 nm. The research was carried out at the NNLOT at KazNU. al-Farabi, where one of the main scientific areas of research is the creation of new types of materials based on carbon nanostructures, in particular fullerenes, as well as their application. A technique for the synthesis of fullerenes was created and developed for their practical application in various industries. A plant for the production of fullerenes based on the method of electric arc evaporation of graphite in a helium medium was launched. The features of the synthesis of fullerenes and their derivatives by the developed method were studied. The technology for obtaining fullerenes in an electric arc discharge at various current values (A) has been developed. Fullerene samples were obtained and analyzed at various current strengths (110A, 135A, 160A, 180A, 200A). The obtained samples were studied both by Raman spectroscopy and by electron and optical microscopy.

New form of carbon is a better diamond

New form of carbon is a better diamond

Subdued Intensity Variation of Graphite Peaks and Variation of Raman Shift in the Synthesis and Characterization of Carbon Nanotubes

Carbon Nanotube (CNT) is a new form of carbon, have aroused huge interest in the research community because of their interesting electronic structure. The CNTs are possibly handy in an extensive variety of solicitations. They unveil phenomenal asset, strange electrical properties and efficient heat conductors. Currently Chemical Vapour Deposition (CVD) has been widely used for the preparing carbon nanotubes because of its simplicity, high throughput and low running cost. It is also easy to control the growth parameters compared to other methods. In the present work methane is used as the source of carbon and ferric nitrate is used as a catalyst. Also, zeolites are used as absorbents and support for catalysts. The growth is carried out in a tubular furnace. The surface morphology, vibrational and structural properties were studied by using FESEM, laser Raman. FESEM micrograph shows the growth of carbon nanotube with different shapes. The length of the tube is ~1.08μm while its diameter is ~70nm. Raman spectra shows the absence of radial breathing mode (RBM) at lower Raman shift and the D and G- band evidence the presence of multi walled carbon nanotubes. XRD pattern reveals that, the intensity of graphite peaks are very subdued because the presence of higher content of zeolite.TGA curve shows, the as grown CNT has a weight gain due to oxidation or oxygen pickup by zeolite. Carbon nanotubes is an advance developing field in research. Carbon nanotubes are the strongest and stiffest materials in terms of tensile strength and elastic modulus. The present work focuses on the growth of Carbon nanotubes using chemical vapour deposition. Although there are many methods, the chemical vapour deposition is chosen because of its simplicity, high throughput and low running cost. Also it is very easy to control the growth parameters compared to other methods. . Carbon nanotubes has a wide application range in the field of Gas sensors, medical science for drug delivery system, field emission, energy storage and solar cells.

Preparation of T-carbon by plasma enhanced chemical vapor deposition

A novel carbon allotrope, T-carbon, is attempted to obtain by using plasma enhanced chemical vapor deposition (PECVD) on the substrates of polycrystalline diamond and single crystalline diamond, respectively. Our measured x-ray diffraction, Raman and infrared spectra of the new form of carbon are in good agreement with the calculated results of T-carbon, and the lattice parameter meets with the results of calculation as well as the high resolution electron microscopy of T-carbon nanowires synthesized by the pulsed laser irradiating modification of carbon multiwall nanotubes, revealing that the phase of T-carbon can be identified in our samples. The experimental preparation of T-carbon by PECVD method indicates that the massive production of T-carbon may be feasible, and extensive investigations with high-throughput experiments on this novel phase are highly expected.

Electrochemical determination of free chlorine on pseudo-graphite electrode

Pseudo-graphite from the University of Idaho Thermolyzed Asphalt Reaction also known as GUITAR is a new form of carbon. It shares morphological features with graphites, including basal and edge planes. Unlike graphites and other sp2-hybridized carbons, GUITAR has fast heterogeneous electron transfer across its basal planes and resistance to corrosion similar to boron-doped diamond electrodes. In this contribution GUITAR electrodes were examined as sensors for aqueous free chlorine (HOCl and OCl−) at pH 7.0 with cyclic voltammetric (CV) and chronoamperometric (CA) methods. Using CV at 50 mV s−1 GUITAR has a limit of detection of 1.0 μmol L−1, linear range of 0–5,000 μmol L−1, sensitivity of 215.8 μA L mmol−1 cm−2 and a signal stability of 4 days in constant exposure to 1 mmol L−1 free chlorine in pH 7.0, 0.1 mol L−1 phosphate buffer system. After 7 days of exposure GUITAR electrodes lost 37% of the former sensitivity, which was recovered by an in-situ regeneration procedure. The common aqueous ions, Ca2+, Na+, NO3-, SO42−, Cl−, CO32− and dissolved oxygen did not affect the response of the GUITAR-based sensor. The combination of limit of detection, linear range, sensitivity, sensor lifetime and its relative lack of interferences indicate that GUITAR is one of the best performers in free chlorine sensors.

Synthetic Variations of Hollow Graphene Nanoshells for Li-Ion Battery Anode

The pyrolysis of cellulose produces bio-fuels, a net carbon neutral energy source, and bio-char that can be used as a soil enhancer. The economic feasibility of the production of bio-fuel from fast growing plants that can grow rapidly on minimally viable land, such as switch grass, would be greatly enhanced by producing higher added value products from the bio-char. Pyrolyzing bio-char in the presence of metal halide catalysts with a CO2laser for a few seconds results in the production of hollow graphene nanoshells (HGNS), a carbon negative material, which can be used in place of graphite active materials in Li-ion battery anodes with remarkably higher charge rate capability and low temperature performance in relatively inexpensive electrolytes. Graphite is the most widely used anode active material in commercial Li-ion batteries. With a standard reduction potential of -2.9 V vs SHE and theoretical gravimetric capacity of 372 mAh/g (at LiC6) it provides 2 to 3 times the energy density compared to aqueous battery chemistries. The challenge remains to charge graphite anodes at the very high rates required for applications such as electric vehicles while maintaining its capacity over thousands of cycles. Shortening the Li-ion diffusion distance in graphite crystallites allows one to increase the charging rate, however, small graphite particles have poor cycle life. We utilize hollow graphene nanoshells that have orders of magnitude shorter diffusion distances than standard graphite as an anode active material. These HGNS are made up of concentric multilayer graphene shells ~50 nm in diameter that intercalate Li+ in manner analogous to graphite but with remarkably higher charge rate capability (up to 22% charge in 7.2 s) and low temperature performance in relatively inexpensive electrolytes such as PC. Unfortunately, the storage capacity for HGNS is lower than graphite (~220 mAh/g vs. ~330 mAh/g practical), which motivated us to investigate synthetic variation to improve HGNS. Here we will present the results of our studies, finding that simple, inexpensive modifications to the synthetic procedures can result in HGNS with 40% greater reversible capacity (320 mAh/g) with no capacity loss after 100 cycles and a Coulombic efficiency of 99.9%. This new form of carbon is a very promising anode active material that could enable Li-ion batteries with dramatically faster charging rates, longer cycle lives and much better low temperature performance than standard graphite anodes. Furthermore, adoption of this carbon negative material in place of synthetic graphite could have a significant impact on global climate change, both directly by CO2 sequestration and indirectly by improving the economic viability of bio-fuels. Figure 1

Adsorption of metal adatom on nanographene: Computational investigations

Recently synthesized nanographene, which is a discrete fragment of graphene, is considered a new form of carbon. We perform density functional theory calculations on the adsorption of various metal adatoms on the saddle-shaped nanographene tetrabenzo[8]circulene (TB8C) and its modified derivates. Our results show that nanographene is better than pristine graphene in adsorbing metal adatoms. Octaamino-tetrabenzo[8]circulene (OA-TB8C) shows the best adsorption capability among the TB8C derivates. Bonding analysis on the metal@nanographene complexes reveals different bonding types for different metal elements. We find that metal adatoms that form ionic bonds or partially covalent bonds with the nanographene have adsorption energies on OA-TB8C that are mostly higher than or close to their own cohesive energies. The saddle geometry of nanographene enables them to adsorb two metal adatoms at the same time, especially for alkali metal atoms.

Novel bilayer graphene structures produced by arc-discharge

A new form of carbon is described, which consists of hollow, three-dimensional shells bounded by bilayer graphene. The new carbon is produced very simply, by passing a current through graphite rods in a commercial arc-evaporation unit. Characterisation of the carbon using high resolution transmission electron microscopy is described, and the possible formation mechanism discussed.

Stable three-dimensional metallic carbon with interlocking hexagons

Design and synthesis of 3D metallic carbon that is stable under ambient conditions has been a long-standing dream. We predict the existence of such phases, T6- and T14-carbon, consisting of interlocking hexagons. Their dynamic, mechanical, and thermal stabilities are confirmed by carrying out a variety of state-of-the-art theoretical calculations. Unlike the previously studied K4 and the simple cubic high pressure metallic phases, the structures predicted in this work are stable under ambient conditions. Equally important, they may be synthesized chemically by using benzene or polyacenes molecules.

Structural Correlations in Heterogeneous Electron Transfer at Monolayer and Multilayer Graphene Electrodes

As a new form of carbon, graphene is attracting intense interest as an electrode material with widespread applications. In the present study, the heterogeneous electron transfer (ET) activity of graphene is investigated using scanning electrochemical cell microscopy (SECCM), which allows electrochemical currents to be mapped at high spatial resolution across a surface for correlation with the corresponding structure and properties of the graphene surface. We establish that the rate of heterogeneous ET at graphene increases systematically with the number of graphene layers, and show that the stacking in multilayers also has a subtle influence on ET kinetics.

Material physics: A new form of carbon

Material physics: A new form of carbon

BUCKYBALLS NAMED A LANDMARK

AWARD-WINNING discoveries are remarkable in and of themselves, but many stimulate great change. The serendipitous discovery of fullerenes is one example. Not only were fullerenes an entirely new form of carbon, but their identification kick-started nanoscience and nanotechnology research and changed the way we think about chemistry and materials. The history of the discovery has been well chronicled, most notably when the scientists responsible won the 1996 Nobel Prize in Chemistry. On Oct. 11, when the 1985 discovery of fullerenes was honored by the American Chemical Society as its 67th National Historic Chemical Landmark, the change it has brought to Rice University, in Houston, was evident as well. The research was conducted in the Rice lab of chemistry and physics professor Richard E. Smalley, who passed away in 2005. The remaining members of the original research team gathered for the chemical landmark ceremony and an informal discussion of their work. Their collaboration was reluctant. Rice ...

”Our work showed how pretty damn good that material is“

AbstractAndre Geim and Konstantin Novoselov were awarded the Nobel Prize in physics ”for groundbreaking experiments regarding the two‐dimensional material graphene“. Nachrichten aus der Chemie asked Andre Geim what he likes most about graphene and if he, too, believes that this new form of carbon could be the silicon of the future.

ChemInform Abstract: Fullerenes - Preparation, Properties, and Carbon Chemistry

Abstract This article reviews the current literature on the new form of carbon based on the fullerene structure. It is now clear that fullerenes can be made from sources other than graphite. Progress has been made in characterising this material by Fourier transform infra red (FTIR), nuclear magnetic resonance (NMR) and mass spectrometric techniques and a wide range of physical measurements have been completed. Potential uses of fullerenes have also been outlined. Fullerene chemistry may also be useful in understanding both coking and soot-forming processes.

First Direct Observation of a Nearly Ideal Graphene Band Structure

Angle-resolved photoemission and x-ray diffraction experiments show that multilayer epitaxial graphene grown on the SiC(0001) surface is a new form of carbon that is composed of effectively isolated graphene sheets. The unique rotational stacking of these films causes adjacent graphene layers to electronically decouple leading to a set of nearly independent linearly dispersing bands (Dirac cones) at the graphene K point. Each cone corresponds to an individual macroscale graphene sheet in a multilayer stack where AB-stacked sheets can be considered as low density faults.

Ceramic and Glass Matrix Composites Containing Carbon Nanotubes

Carbon nanotubes (CNTs) are promising reinforcing elements for structural composites due to their remarkable mechanical properties. The impressive electrical and thermal properties of this new form of carbon also make CNTs containing composites ideal candidates for multifunctional applications. In the past decade, researchers have investigated CNTs as toughening inclusions to overcome the intrinsic brittleness of ceramics and glasses. Although there are numerous investigations available in the literature, a significant progress has not occurred or it has been rather slow compared to advances in the field of CNT/polymer matrix composites. This paper reviews current trends in research and development efforts on the use of CNTs for fabrication of ceramic and glass matrix composite materials. The review includes a summary of key issues related to the optimisation of CNT-based composites and an overview of investigations dealing with processing techniques developed to optimise dispersion quality, interfaces and density. The mechanical properties of as-produced composites are discussed and a comprehensive comparison of data available for different matrix materials is presented. Finally, the potential applications of the resulting CNT/inorganic matrix composites and the scope for future developments in the field are highlighted.

The enhanced anodic performance of highly crimped and crystalline nanofibrillar carbon in lithium-ion batteries

To find a novel high-performance anode material for lithium-ion batteries, a new form of carbon characterized by highly crimped and crystalline nanofibrillar microtextures was produced by heat treating polyacrylonitrile/FeCl 3 hybrid precursor and subsequent thermal annealing under hydrogen gas. This form of carbon exhibits a rechargeable capacity of ∼630 mAh/g, which is superior to that of graphite, with a Coulomb efficiency of ∼70%. Further, the new form of carbon was found to exhibit an efficiency of lithium ion insertion/extraction of ∼100% in the voltage range from 0.06 to 0.80 V, with a capacity of ∼400 mAh/g. We speculate that this excellent capacity is due to the characteristic structure of this form of carbon, i.e. its highly entangled web-like hyperstructure consisting of highly crimped and crystalline nanofibrillar microtextures, which enables good permeation and has high resilience to volume deformation during the insertion/extraction of Li ions.

Densified aligned carbon nanotube films via vapor phase infiltration of carbon

We report a simple way to produce fully densified aligned carbon nanotube (ACNT) films. The simultaneous growth of nanotubes and densification of the ACNT films by carbon infiltration in the interstitial spaces between nanotubes are accomplished in a single step by the combination of the chemical vapor deposition and chemical vapor infiltration processes. Scanning electron microscope analysis and microbalance measurements showed that after infiltration, the diameters of nanotubes and bulk density of the ACNT films are increased by an order of magnitude (and hence the porosity of the ACNT films is decreased). Transmission electron microscope and Raman scattering analysis showed that after densification, the nanotubes are conformally coated by partially graphitized pyrolytic carbon. The compressive modulus of the densified ACNT films could be increased by three orders of magnitude compared to the pristine ACNT films. Electrical properties are also measured for the densified films showing marked differences with the ACNT films. The property enhanced densified ACNT films constitute a new form of carbon–carbon nanocomposites and could find applications as multifunctional nanocomposites.

Free-Flowing Carbon Nanosheets - A New Form of Carbon

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C60 Intercalated Graphite: A New Form of Carbon

A carbon solid containing two carbon allotropes, C60 and graphite has been synthesized. In this solid, the two dimensional layers of C60, stacked in between every graphite layers, show long range ordering with average separation of 1.27 nm between C60 layers. Predominantly stage‐1 along with stage‐4 is obtained. An up‐shift in the graphite E2g2 Raman mode and a downshift in the C60 Raman Ag2 mode occurred due to a charge transfer and indicated highly conducting state of C60. This C60‐graphite intercalation compound can act as a host for co‐intercalation of alkali‐metals and may lead to a new superconductors.