Structures and Images of Novel Derivatives of Carbon Nanotubes, Fullerenes and Related New Carbon Forms

In the light of the finding that carbon nanotubes get functionalized on reaction with acid and other oxidizing agents, the structures and shapes of nanotube derivatives resulting from possible reaction between functionalized nanotubes, are obtained by an energy minimization procedure and the structures, so obtained, are compared with the observed microscopic images. The shapes of fullerene -like and nanotupe - like structures containing seven - membered rings, in addition to six and five - membered rings, are depicted along with the structures of bent nanotubes containing similar ring systems. Diamond - graphite hybrid structures which constitute an important class of carbon materials are also investigated.     

Shungite Carbon and Fullerenes

Thermpgravimetry method applied to shungite carbon (ShC) was the next step which testified its similarity with fullerenes. Fullerene-like approach suggested earlier was helpful in understanding shungite nature. ShC behavior under heating in air confirmed the structure ordering and its metastability.     

Shungite Carbon and Fullerenes

Abstract

Thermpgravimetry method applied to shungite carbon (ShC) was the next step which testified its similarity with fullerenes. Fullerene-like approach suggested earlier was helpful in understanding shungite nature. ShC behavior under heating in air confirmed the structure ordering and its metastability.     

Charge Transfer and the Route to Superconductivity in the Doped Fullerenes

A brief review is presented discussing the role of charge transfer and the appearance of superconductivity in the three-dimensional (3D) alkali-metal-doped fullerene compounds (A₃C₆₀). An argument is made that similar phenomenology may occur in two dimensions (2D) when a C₆₀ monolayer is doped by charge transfer from an adjacent planar metal layer. Illustrative data are presented showing that charge transfer gives rise to a decrease in resistance when C₆₀ is deposited onto a thin smooth nickel film. Accordingly, the physics of charge transfer and electron delocalization, which plays such an important role in the superconductivity of the 3D A₃C₆₀ compounds, could well play a similar role in these 2D analogues where a C₆₀ monolayer is doped to a conducting state by charge transfer from an underlying metal.     

Production of Fullerenes by Combustion

Abstract

The progress in the production of fullerenes from flaming soot is reviewed in terms of the experimental conditions, characteristics in the product distribution, and formation mechanisms.     

Production of Fullerenes by Combustion

The progress in the production of fullerenes from flaming soot is reviewed in terms of the experimental conditions, characteristics in the product distribution, and formation mechanisms.     

Nitrogen‐Doped Carbon Membrane Derived from Polyimide as Free‐Standing Electrodes for Flexible Supercapacitors

Nitrogen‐doped carbon materials have attracted great interest in the energy storage due to the better electrochemical performances than the pristine carbon materials. In this work, a heterocyclic polyimide containing benzopyrrole and benzimidazole rings is carbonized to fabricate the free‐standing and flexible carbon membrane (Carbon_PI) with a high packing density (0.89 cm^?3), in which the location of nitrogen atoms in the doped configurations is easily controlled. XPS analysis indicates that quaternary nitrogen is the predominant nitrogen‐doped configurations. The high content of nitrogen effectively improves the wettability of the electrode materials. The Carbon_PI membrane exhibits excellent volumetric capacitance (159.3 F cm^?3 at 1 A g^?1), high rate capability (127.5 F cm^?3 at 7 A g^?1), and long cycle life. TEM images reveal the very slight change of the microstructure of graphitic nanosheet of Carbon_PI during the long charge/discharge cycles.     

Carbon and Nickel Oxide/Carbon Composites as Electrodes for Supercapacitors

The carbon and nickel oxide/carbon composite electrodes were prepared by plasma jet and magnetron sputtering techniques.The investigations were performed to evaluate the influence of the Ar/C 2 H 2 ratio on the specific capacitance values of carbon and NiO/carbon electrodes.The obtained electrodes were investigated by scanning electron microscopy,Raman scattering spectroscopy(RS),and X-ray diffraction techniques.The surface of the carbon electrodes became less porous and more homogenous with increasing Ar/C 2 H 2.The RS results indicated that the fraction of the sp 2 carbon sites increased with increasing Ar/C 2 H 2 ratio.The increase of the Ar/C 2 H 2 ratio increased the capacitance values from 0.73 up to 3.6 F/g.Meanwhile,after the deposition of the nickel oxide on the carbon,the capacitance increased ten and more times and varied in the range of 7.6-86.1 F/g.     

Fullerenes,Carbon Chains,and Interstellar Matter

Spectroscopy of carbon particles, fullerenes, and carbon chain molecules was the subject of a considerable part of my research work, as described in this article. In almost all cases, there existed a tight connection to problems in astrophysics and astrochemistry, aiming at a better understanding of interstellar matter. The bulk synthesis of fullerenes was a by-product of these efforts.     

An Invariant of Carbon Arc Synthesis of Fullerenes

Abstract

The yields of fullerenes C₆₀ and C₇₀ were determined in a wide range of controlled parameters. The total yield of fullerenes varied from 3 to 24%. The molar relative contents C₆₀/C₇₀ appeared to be constant for all samples of toluene extracts of the soot and equal to 5.06 ± 0.1. The accuracy of this constancy (± 2%) was determined by application of a special mathematical processing to the spectra of toluene extracts.     

Automatic Production of Fullerenes by A JxB ARC Jet Discharge Preventing Carbon Vapor from Depositing on the Cathode

Deposition of carbon atoms on a cathode in a DC arc discharge to produce fullerenes is reduced by JxB force of a magnetic field in an arc flame. By this modification, more effective synthesis of fullerenes and easier control of discharge conditions are achieved.     

An Invariant of Carbon Arc Synthesis of Fullerenes

The yields of fullerenes C₆₀ and C₇₀ were determined in a wide range of controlled parameters. The total yield of fullerenes varied from 3 to 24%. The molar relative contents C₆₀/C₇₀ appeared to be constant for all samples of toluene extracts of the soot and equal to 5.06 ± 0.1. The accuracy of this constancy (± 2%) was determined by application of a special mathematical processing to the spectra of toluene extracts.     

The Formation of Fullerenes from Sonic Velocity Gaseous Carbon

A contact are and adiabatic expansion hybrid reactor has been utilized to provide a controlled cooling process of gaseous carbon species capable of attaining very high velocities. Both vaporization and annealing temperatures and annealing time were found to be impartant for the formation of fullerenes. Immediate rapid quenching of gaseous carbon resulted in the reduction of fullerene yields. However, rapid quenching was demonstrated to improve the fullerene yield by preserving the as-grown fullerenes in the high temperature annealing process.     

The Formation of Fullerenes from Sonic Velocity Gaseous Carbon

Abstract

A contact are and adiabatic expansion hybrid reactor has been utilized to provide a controlled cooling process of gaseous carbon species capable of attaining very high velocities. Both vaporization and annealing temperatures and annealing time were found to be impartant for the formation of fullerenes. Immediate rapid quenching of gaseous carbon resulted in the reduction of fullerene yields. However, rapid quenching was demonstrated to improve the fullerene yield by preserving the as-grown fullerenes in the high temperature annealing process.     

Optimization of Conditions for Preparation of Carbon Origin Solid Electrodes Modified with Carbon Nanotubes

A multi-walled carbon nanotubes (MWCNTs) were used for modification of two solid electrode types, glassy carbon electrode (GC), which is widely used for modification in electroanalysis, and, for the first time, paraffin impregnated graphite electrode (PIGE). The optimization of MWCNT/PIGE and MWCNT/GC electrodes was carried out by altering ultrasonication parameters (ultrasonication time, ultrasound generator performance, and dispersing agent). The preparation of modified electrodes was investigated. The most electrochemically sensitive MWCNT/GC electrode was prepared with nanotubes sonicated for 30 min and the most sensitive MWCNT/PIGE for 20 min, both using ethanol/water solution as dispersing agent and 500 W ultrasound generator performance. Both electrodes were successfully used for analysis of lead performed by DC voltammetry. Current responses were measured for the concentration of lead (II) in range from 1 × 10^?5 to 5 × 10^?5 mol dm^?3 for MWCNT/PIGE and also MWCNT/GC electrode.     

2D and 3D Crystal Forms of the C36 Fullerenes: Geometrical and Electronic Structure

Abstract

In the present work calculations of geometrical structure and electronic properties of the covalent crystal consisted of hexagonal close packaged layers of C₃₆ fullerenes in 2D & 3D cases are carried out. The analysis of the stability and formation paths of such crystal according to PM3 semiempirical method was performed. Extended Huckel theory has been applied to electron spectra calculations. Comparison of the structure with similar fullerene and nanotube structures was carried out and effect of geometry to electron properties is discussed. In the work the values of 6.695 and 6.763 Å for the lattice constants were obtained with good agreement with experiment (Piskoti, C.; Yarger, J.; Zettl, A. C₃₆, a new carbon solid. Nature 1998, 393, 771), and value of 1.50 eV in 2D case and 1.88 eV in 3D case was obtained for bandgap.     

Production of Fullerenes from Plant Materials and used Carbon Materials by Means of a Chip-Injection-Type J×B Arc Reactor

By using a chip-injection-type J×B arc reactor, carbon material chips of, for example, charcoal, activated carbon, sumi (Chinese ink stick), synthetic rubber and carbon black are well arc-sublimated in He gas and fullerenes are successfully produced from these materials. From the viewpoints of effective use of plant resources, recycling of used carbon materials and environmental low-emission technology, the utilization of these materials to produce fullerenes has potential as an environment-friendly technology.