Search

Abstract: We have evaluated the biological responses to four different types of carbon nanotubes (CNTs), by measuring CD4+ and CD8+ T-cells in peripheral blood, and by the histopathological study on tissues surrounding subcutaneously implanted CNTs for up to 3 months. All mice survived, and no large changes in their weights were observed within our experimental period. After 1 week, only single-walled carbon nanotubes (SWNTs) activated major histocompatibility complex (MHC) class I pathway of antigen–antibody response system (higher CD4+/CD8+ value), resulting in the appearance of an edematous aspect. After 2 weeks, significantly high values in CD4+ and CD4+/CD8+ without change in CD8+ signified an activated MHC class II for all samples. It is worth noting that the toxicological response of CNTs was absolutely lower than that of asbestos. As a result, we envisaged that our result (relatively low toxicity of CNTs) will spur the mass-production, as well widespread application of CNTs in the near future. [Copyright &y& Elsevier]

Abstract: Carbon nanofiber–copper composite films with different types of nanofibers were fabricated by an electrodeposition process. Four types of carbon nanofibers, vapor-grown carbon nanofibers without heat treatment, vapor-grown carbon nanofibers with heat treatment, vapor-grown carbon nanofibers with smaller diameters, and vapor-grown carbon nanofibers with a cup-stacked nanostructure were used. The carbon nanofibers were homogeneously dispersed in sulfate copper plating baths in the presence of polyacrylic acid. Electrodeposition was carried out under galvanostatic conditions using these copper plating baths. The deposition resulted in electrodeposited copper films containing the carbon nanofibers distributed homogeneously. The surface morphology of the carbon nanofiber–copper composite films was observed to be affected by the type of carbon nanofiber used. [Copyright &y& Elsevier]

Multi-walled carbon nanotubes (MWNTs), having a diameter around 100–200 nm, were used as host material for electrodeposition of Ni using a Ni plating bath containing homogeneously dispersed MWNTs. Ni-deposited or coated MWNTs with a skewered dumpling shape accumulated on the Cu cathode electrode. A model representing the growth process of these electrodeposits, which possess such a skewered dumpling shape, is presented. These electrodeposits were separated easily from the cathode electrode by ultrasonic irradiation in an acetone bath to yield a Ni-deposited or coated MWNTs powder. The amount of Ni deposited on the MWNTs can be controlled by selecting the appropriate electroplating conditions. [Copyright &y& Elsevier]

We investigated the stable structures, electronic and Li-adsorption properties of C 54 H 18 and its substituted sheets X 2 C 52 H 18 (X=B, N, Si, P, S, Al and F) by a semiempirical molecular orbital method. The F 2 C 52 H 18 sheet was found to have a unique structure and adsorb more Li atoms than the other sheets. This result suggests that the F-substitution into disordered carbons may increase the Li-storage in disordered carbons. [ABSTRACT FROM AUTHOR]

Nanocarbons, which have been obtained by controlling the structure and bonding nature at the nanometer scale, can provide highly functional performances. Carbon nanotubes and vapor grown carbon fibers of diameter less than 100 nm can have quantum effects, which are very different from those of conventional carbon fibers. In this paper, preparation and properties of nanocarbon, are demonstrated and discussed. [ABSTRACT FROM AUTHOR]

To clarify the effect of atom substitution on electronic and lithium (Li) adsorption properties of disordered carbons, we employed circum-coronene (C54H18) as a model cluster for disordered carbons and investigated the stable structures, electronic and Li-adsorption properties of its sulfur-, phosphorus- and silicon-substituted sheets, by using a semiempirical molecular orbital method. Among the three substituted sheets, the silicon-substituted Si2C52H18 sheet was found to have desirable properties as an anode material of rechargeable Li-ion batteries: planar structure and large amount of Li adsorption. Although the Li-adsorption energy of Si2C52H18 is smaller than that of B2C52H18, the dependence of adsorption energy on the number of Li atoms indicates that Si2C52H18 can adsorb more Li atoms than B2C52H18. Therefore, silicon- as well as boron-substituted disordered carbons are expected to be promising materials for the anode in Li-ion batteries. [Copyright &y& Elsevier]

This article provides information on a study that examined the electrical conduction of carbon black (CB). Information is presented on the method used to measure the electrical resistivity of the CB samples. The structure of electrically conductive CB is discussed, as well as current-voltage characteristics of the samples.

Data science has been rapidly developed and implemented in diverse scientific and technological fields over the past decade, to accelerate new knowledge generation and develop high‐impact applications. Recently, different data science tools and techniques have been widely used, such as optimizations, regressions, and classifications of data (tabular, spectral, or visual). In this review, data science tools and techniques are discussed for their adoption for the synthesis, characterization, and applications of carbon‐based materials. Materials synthesis in conjunction with data science has resulted in optimal growth conditions with desired properties and processing techniques. Regarding characterization, molecular structures can be reconstructed using microscopy images, and a particular property can be predicted based on the other properties of the desired carbon material. Moreover, for the applications of carbon materials, data science has enabled prediction of the water treatment efficiency, classification of electronic signals, prediction of the biological activity, and virus classification. It is clear that by combining data science and carbon‐related materials, it is now possible to accelerate theory‐experimental research in the quest for novel materials and their emerging applications. [ABSTRACT FROM AUTHOR]

Nickel-coated carbon nanofibers have been prepared by an electroless deposition process. The carbon nanofibers were pre-treated prior to the nickel electroless deposition. Polyacrylic acid was used to disperse carbon nanofibers in the pre-treatment solutions. The carbon nanofibers were coated homogeneously with nickel by the electroless deposition process using an electroplating bath containing sodium hypophosphite as a reducing agent. The process resulted in a powdery-nickel-coated carbon nanofiber material. [Copyright &y& Elsevier]

Carbon nanofiber–copper composite powder is prepared by an electrodeposition process using a copper plating bath containing homogeneously dispersed carbon nanofibers. Particles of the composite with a spiky ball structure are accumulated on the plating electrode during the initial stage of electroplating, and can be separated easily to give a powder carbon nanofiber–copper composite. The particle size can be controlled by selecting appropriate electroplating conditions. [Copyright &y& Elsevier]

This paper presents analytical models of wave propagation in single- and double-walled carbon nanotubes, as well as nanotubes embedded in an elastic matrix. The nanotube structures are treated within the multilayer thin shell approximation with the elastic properties taken to be those of the graphene sheet. The double-walled nanotubes are coupled together through the van der Waals force between the inner and outer nanotubes. For carbon nanotubes embedded in an elastic matrix, the surrounding elastic medium can be described by a Winkler model. Tube wave propagation of both symmetrical and asymmetrical modes can be analyzed based on the present elastic continuum model. It is found that the asymmetrical wave behavior of single- and double-walled nanotubes is significantly different. The behavior is also different from that in the surrounding elastic medium. [ABSTRACT FROM AUTHOR]

The article presents a research on the process of producing mesoporous carbon aerogels with hydrophilicity-controlled pore walls. Researchers state that, the process uses carbon dioxide supercritical drying to form interconnected micropores and small mesopores, and at the same time, uses colloidal silica nanocasting to form larger mesopores and increase pore volumes. It is stated that, the controlled removal of the silica from the pore walls increases the nanoporosity of the walls.

In article number 2100205, Morelos-Gomez, Terrones and Endo explore how, with the aid of tools from data science, carbon nanomaterials research and development can accelerate in three key experimental areas: synthesis, characterization, and applications. B Data Science Applied to Carbon Materials b Carbon materials have been the main subject for two Nobel prizes; they exhibit excellent physical and chemical properties that have been used in diverse applications. Data Science Applied to Carbon Materials: Synthesis, Characterization, and Applications (Adv. [Extracted from the article]

Abstract: Rubber composite sheets filled with 5wt.% and 30wt.% of highly aligned carbon nanotubes (CNTs) were fabricated through conventional rubber technology. The alignment of CNTs was possibly derived from dragged shear force during the optimized milling process. The selective alignment of CNTs led to enhancements in the elastic modulus, thermal conductivity, electrical conductivity, and electromagnetic shielding property, compared to neat rubber sheet. [Copyright &y& Elsevier]

Abstract: The multi-walled carbon nanotubes (MWCNTs, mean diameter: 100–200nm) with nickel–phosphorous (Ni–P) coatings were obtained by an electroless deposition process. To prepare the MWCNTs covered with continual Ni–P layers, a pre-treatment procedure comprised of acid-cleaning, sensitization and activation has been developed. The resulting MWCNTs have a uniform distribution of the Ni–P layers coated on the MWCNTs with the fibrous appearance maintained. X-ray diffraction (XRD) and transmission electron microscopy (TEM) observations revealed that the as-coated MWCNTs were comprised of the amorphous Ni–P layers and inner carbon nanotubes covered with the Ni–P layers. These amorphous Ni–P-coated MWCNTs were used as precursors for preparing MWCNTs with nanocrystalline Ni–P(crystalline Ni and Ni3P intermetallic compound) layers by the heat-treatment above 400°C, which were determined by differential scanning calorimeter (DSC) and XRD studies. The results of this work provide an effective electrochemical method for preparing powdery MWCNTs with Ni–P layer as new composite materials from the aqueous solution. [Copyright &y& Elsevier]

Based on a link between molecular and solid mechanics, an analytical method was developed for modeling the elastic properties of single-walled carbon nanotubes (SWNTs). A SWNT is regarded as a continuum-shell model which is composed of the discrete molecular structures linked by the carbon-to-carbon bonds. The elastic properties were investigated for the SWNTs as a function of the nanotube size in terms of the chiral vector integers (n,m). The theoretical prediction on elastic properties agreed reasonably with the existing experiment and theoretical results. The present formulas are able to serve as a good approximation of the elastic properties for SWNTs. [Copyright &y& Elsevier]

Two different processes, which lead to formation of multishell fullerenes, are reported and discussed. The first process is 3000°C high temperature treatment of C 60 -containing carbon blacks. The second process is laser vaporization of composite carbon targets, containing C 60 and vapor-grown carbon fibers (VGCF). It has been shown that the laser vaporization technique allows increasing the yield up to 40%. Possible mechanisms of formation of the outer shells are discussed. [ABSTRACT FROM AUTHOR]

An advantageous procedure has been developed, allowing metallization of multi-walled carbon nanotubes (MWCNTs, mean diameter: 50–80 nm) with Cu layer by an electroless deposition process. Such a procedure for achieving electroless Cu deposition on MWCNTs involves acid pre-clean, sensitization and activation. Results show that metallizated MWCNTs keep the fiber-like appearances with uniform distribution. This resulting nanotube-derived material is comprised of a nanocrocrystalline Cu layer and inner nanotube covered with Cu layer. The results of this work have demonstrated the effectiveness of electroless deposition on the metallization of MWCNTs. [Copyright &y& Elsevier]

We introduce a way to selectively probe local vibration modes at nanostructured asperities such as tips of carbon nanohorns. Our observations benefit from signal amplification in surface-enhanced Raman scattering (SERS) at sites near a silver surface. We observe nanohorn tip vibration modes in the range 200-500 cm-1, which are obscured in regular Raman spectra. Ab initio density functional calculations assign modes in this frequency range to local vibrations at the nanohorn cap resembling the radial breathing mode of fullerenes. Careful interpretation of our SERS spectra indicates presence of caps with 5 or 6 pentagons, which are chemically the most active sites. Changes in the peak intensities and frequencies with time indicate that exposure to laser irradiation may cause structural rearrangements at the cap. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials offer exciting potential for applications in many fields including electronics, optics, catalysis and energy storage. Recently, materials such as graphene, boron nitride, molybdenum sulfide and tungsten sulfide have been widely studied due to their availability, easy synthesis and fascinating properties. The combination of two or more of these 2D materials into hybrid assemblies provides a unique way to obtain novel properties different from those of the parent materials. This review examines recent literature on the synthesis and preparation of 2D hybrid material assemblies and some potential applications such as photo-detection, battery performance and efficient catalysis. We also discuss some of the future challenges that need to be addressed in the near future in this emerging field. [ABSTRACT FROM AUTHOR]

The potential of cup-stacked-type carbon nanotubes (CSCNTs) as a catalyst support for the direct methanol fuel cells has been investigated by the electrochemical oxidation of methanol at various temperatures. The CSCNT-supported platinum–ruthenium (Pt–Ru) bimetallic catalyst exhibited twice as high a power density as the Pt–Ru catalyst supported on Vulcan XC-72 carbon, which is widely used as a catalyst support for the DMFC electrodes. The microscopic analysis of the CSCNT-supported Pt–Ru catalysts revealed that the bimetallic electrocatalysts were well dispersed on the CSCNT supports, and the particle size of the electrocatalysts was ca. 5 nm. The results of this work indicate that the performance of the carbon support materials is largely influenced by their electrical properties, morphology and crystallographic structures. [ABSTRACT FROM AUTHOR]

The article presents chemistry research which describes a nanowindow-regulated capacitance of supercapacitor electrodes of single-wall carbon nanohorns. Results reveal the use of single-wall carbon nanohorns with larger nanoscale-hole size could result in the fabrication of high-capacitance supercapacitors that utilize organic electrolytes.

Abstract: Vertically-aligned carbon nanosheets (CNSs) have been fabricated on the Cu substrate from Kapton polyimide (PI) film under Ar/H2 plasma irradiation. The high purity CNSs possess petal-like structures with many sharp edges, which are composed of few-layer graphene sheets. In addition, the irradiated Kapton PI film was covered by a layer of urchin-like carbon particles with about 4μm in diameter, which also consist of few-layer graphene sheets along radial directions. Except for the morphologies, both the CNSs and urchin-like carbon particles demonstrate similar microstructures and chemical compositions. [Copyright &y& Elsevier]

The electronic interactions between the [Cu(opba)]2− anions (where opba is orthophenylenebis (oxamato)) and single-wall carbon nanotubes (SWCNTs) were investigated by resonance Raman spectroscopy. The opba can form molecular magnets, and the interactions of opba with SWCNTs can produce materials with very different magnetic/electronic properties. It is observed that the electronic interaction shows a dependence on the SWCNT diameter independent of whether they are metallic or semiconducting, although the interaction is stronger for metallic tubes. The interaction also is dependent on the amount of complex that is probably adsorbed on the carbon surface of the SWCNTs. Some charge transfer can be also occurring between the metallic complex and the SWCNTs. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Graphene and graphitic nanoribbons possess different types of carbon hybridizations exhibiting different chemical activity. In particular, the basal plane of the honeycomb lattice of nanoribbons consisting of sp2-hybridized carbon atoms is chemically inert. Interestingly, their bare edges could be more reactive as a result of the presence of extra unpaired electrons, and for multilayer graphene nanoribbons, the presence of terraces and ripples could introduce additional chemical activity. In this study, a remarkable irreversibility in adsorption of CO2 and H2O on graphitic nanoribbons was observed at ambient temperature, which is distinctly different from the behavior of nanoporous carbon and carbon blacks. We also noted that N2 molecules strongly interact with the basal planes at 77 K in comparison with edges. The irreversible adsorptions of both CO2 and H2O are due to the large number of sp3-hybridized carbon atoms located at the edges. The observed irreversible adsorptivity of the edge surfaces of graphitic nanoribbons for CO2 and H2O indicates a high potential in the fabrication of novel types of catalysts and highly selective gas sensors. [ABSTRACT FROM AUTHOR]

Abstract: We fabricated nitrogen-decorated porous carbon exhibiting high capacitance per unit volume and unit weight via chemical activation of novolac resin containing peptide linkage. The porosity and the amount of nitrogen atoms were controlled by changing the molecular weight of novolac resin, the added amount of potassium hydroxide, or both. After chemical activation, positively charged nitrogen atoms (i.e., pyridine/pyrrole) at 400.3eV in photoemission spectra contributed to both a shift in the point of zero charge toward negative potential and the generation of pseudocapacitance. Suitably developed pores and the positively charged nitrogen atoms make nitrogen-decorated novolac resin-derived porous carbon a promising material for electrodes in high-performance supercapacitors. [Copyright &y& Elsevier]

Abstract: The quantitatively limited use of hydrogen peroxide in supercritical water allows for the in situ formation of iron oxides and graphitic carbon from ferrocene in one step. The structure of the particles prepared at 400–500°C is comprised of nano- to micro-meter size of magnetite and maghemite cores covered with graphitic carbon shells. The morphology and size of the core–shell particles and the phase composition of iron-oxide cores are different dependent on the preparation conditions. The particles prepared at 400°C contain, as dominant iron-oxide phase, the magnetite core particles ranging from nano- to micro-meter scales with no morphological regularity, while those prepared at 500°C are comprised of hexagram shape and micro-meter size of maghemite cores. The observed morphology, the dimension of the core particles, and the dominant phase composition suggested that the iron-oxide cores would be formed through the oxidation of iron(II) to iron(III) and two different hydrolysis paths. Furthermore, the higher preparation temperature of 500°C has shown a tendency to form smaller crystallite sizes of polycrystalline iron-oxide cores. The decrease of subcrystal sizes in the vicinity of superparamagnetic thresholds effects the reduction of coercivity in the ferromagnetic hysteresis. [Copyright &y& Elsevier]

Abstract: A novel nitrogen-rich carbon material, silk carbon, was prepared from Bombyx mori silk fibroins by simple heat-treatment under inert atmosphere. The nitrogen atoms were originated from copious peptide bonds contained in the silk fibroins. The adequate heat-treatment temperature turned the nitrogen atoms of the peptide bonds to the silk carbons in the form of nitrogen-containing functional groups. Furthermore, the activation of the silk carbons with steam and potassium hydroxide provided nitrogen-containing activated carbons (ACs) with different pore-size distribution. In the application to electric double layer capacitors, the silk carbon-based ACs showed a higher capacitance and an excellent electrochemical stability in the high voltage region, compared with a typical AC prepared from phenolic resin. More significantly, the steam-activated silk carbon showed the energy density that was comparable to that of the phenolic resin-based AC prepared by chemical activation. This indicates the superiority of steam-activated silk carbons to conventional KOH-activated carbon materials in supercapacitor application, due to the low production cost by the facilities of steam activation, and the relevant capacitance comparable with that of chemical activation. [Copyright &y& Elsevier]

Abstract: Multiwalled carbon nanotubes were used as filler to furan resin in the aim of producing an electrically conducting polymer composite that may be useful for electrode applications. The orientation of the nanotubes is controlled to prepare a composite with fillers unidirectionally oriented, which may result in higher electrical conductivity at one direction and at lower nanotube loading. Using the doctor blade technique, composite films were prepared and the alignment and its effect on the electrical conductivity of the composite were investigated. It was found that the doctor blade technique induced preferential alignment of the nanotubes in composite and a higher degree of alignment is achieved in composites with lower contents of nanotubes. Also, for low contents of nanotubes, the electrical conductivity of the composite with preferentially aligned nanotubes was up to a million times higher in the direction of alignment compared to that of the composite with randomly oriented nanotubes; however, at higher contents of nanotubes, this effect was diminished. The preferential alignment of the nanotubes also caused anisotropic electrical conductivity. The alignment and distribution is thought to create more junctions between nanotubes that resulted into the formation of more conducting channels in the polymer matrix parallel to blading direction. [Copyright &y& Elsevier]

Abstract: Carbon spheres (CSs) have been subjected to a high temperature annealing process at 2800°C under an Ar atmosphere. These high temperature annealed carbon spheres (HTACSs) have been characterised by SEM, HRTEM, BET surface area, XRD, Raman, SQUID and TGA techniques. The study indicates that the original spheroidal morphology of CSs have been converted to polyhedral. The graphitic flakes possessing relatively short range order of which the original are composed of appear to have coalesced into more extended graphitic layers possessing long range order. Furthermore three dimensional interplanar graphitic ordering occurs. Charge–discharge capacity measurements have been performed on both carbon materials to access the potential of these materials in Li-ion secondary battery applications. The measurements indicate that HTACSs exhibit better performance than CSs in terms of greater reversible capacity and their longer plateau in voltage profiles. [Copyright &y& Elsevier]

Abstract: Here, we carried out Raman study on chemically doped single wall carbon nanotube (SWNT)/double-walled carbon nanotube (DWNT) mixed bucky-papers. Their highly different Raman responses (e.g., a large upshift of tangential mode of SWNT and no large changes in the frequencies of tangential mode assigned to the outer tubes of the DWNT) upon doping with the sulfuric acid could be used as a qualitative indicator of the purity of the DWNT samples with the concentration of its SWNTs contents. [Copyright &y& Elsevier]

Abstract: The effect of the dispersion, ozone treatment and concentration of cup-stacked carbon nanotubes on mechanical, electrical and thermal properties of the epoxy/CSCNT nanocomposites were investigated. Ozone treatment of carbon fibers was found to increase the surface oxygen concentration, thereby causing the contact angle between water, epoxy resin and carbon fiber to be decreased. Thus, the tensile strength, modulus and the coefficient friction of carbon fiber reinforced epoxy resin were improved. Moreover, the dispersion of fibers in polymer was increased and the electrical resistivity was decreased with the addition of filler content. The dynamic mechanical behavior of the nanocomposite sheets was studied. The storage modulus of the polymer was increased by the incorporation of CSCNTs. But the glass transition temperature decreased with increasing fiber loading for the ozone treated fiber composites. The ozone treatment did affect the morphology, mechanical and physical properties of the CSCNT. [Copyright &y& Elsevier]

Two classes of carbon materials with different microstructures were chosen for electric double layer capacitors (EDLCs). One is a mesophase pitch-based carbon fiber (MPCF). The other is an isotropic pitch-based carbon fiber (IPCF). Both series of samples were activated by KOH with varying the KOH addition fraction. The MF-series prepared from MPCFs by several KOH fractions exhibited a good capacitance in comparison with the IF-series prepared from IPCFs, although the former had smaller specific surface areas than those of the latter. The specific capacitance per weight (F/g) of both samples increased with an increase in KOH fraction. Further evaluation of the capacitance using the specific capacitance per unit area elucidates the efficiency of the surface area. The MF-series prepared by the addition of 200–250 wt.% KOH showed a larger capacitance per unit volume and surface area under the same charge/discharge conditions, despite their smaller specific surface areas. [Copyright &y& Elsevier]

Polyparaphenylene (PPP)-based carbon is expected for a high-performance material of a negative electrode of lithium (Li) ion secondary battery, but the details of relationship between characteristics and heat treatment have not been known. In this report, electrochemical and electrical properties of heat-treated PPP-based carbon powder were investigated and the possibility of the use as the negative electrode of Li ion secondary batteries was shown. [ABSTRACT FROM AUTHOR]

Structural characterization of novel nanofibers, so called "cup-stacked type carbon nanofibers" with large hollow core and their potential applications are described as compared with those of tubular type of nanotubes and nanofibers. This novel carbon nanofiber containing peculiar features provide the variety of carbon nanotubes and nanofibers from basic science to application field. [ABSTRACT FROM AUTHOR]

Structural changes of truncated graphitic conical graphene layers (cups) stacked carbon nanofiber by post-treatment, such as oxidation and heat treatment, are described in terms of microstructure and morphology. [ABSTRACT FROM AUTHOR]

Recently, the lattice image of well ordered carbons can be observed pretty easily by high-resolution transmission electron microscopy (HRTEM). In this study, the cross section of the new type carbon nanofiber, of which the special structure was unknown, was observed by HRTEM and the detailed structure was analyzed by image processing. Defects were observed in the ordered structure of this material, that is, the (00·1) lattice planes show large fluctuation in alignment of them and the (10·0) lattice planes make several angles with the (00·1) lattice planes. The average repeat distance d 002 was estimated by HRTEM image and image analysis. [ABSTRACT FROM AUTHOR]

High-resolution transmission electron microscopy study of ball-milled lampshade carbon nanofibers is reported in the present paper. Milled fibers became shorter in length, preserving the lampshade structure with highly ordered graphene layers. We have also shown the simulated model for the shortening process of the fiber. [ABSTRACT FROM AUTHOR]

Abstract: Carbon black–silver hybrid catalysts were easily synthesized by a mixing method of acid-oxidized carbon black and the colloidal dispersion of silver nanoparticles. The silver colloidal dispersion was pre-synthesized by a chemical reduction of silver nitrate by dimethyl sulfoxide in the presence of trisodium citrate dihydrate as capping agents. In the mixing method, approx. 6.0 nm diameters of silver nanoparticles with face-centered cubic crystal structures are highly dispersed on the acid-oxidized carbon blacks due to the surface reactivity resulting from the enhancement of oxygen-containing functional groups. The hybrid catalysts were examined for electro-catalytic activity towards oxidation of hydrazine. The results clearly show that the carbon black–silver hybrid catalysts are highly active for electro-catalytic oxidation of hydrazine. [Copyright &y& Elsevier]