Showing papers on "Nanotube published in 2012"
TL;DR: It is shown that few-walled carbon nanotubes, following outer wall exfoliation via oxidation and high-temperature reaction with ammonia, can act as an oxygen reduction reaction electrocatalyst in both acidic and alkaline solutions.
Abstract: Oxygen reduction reaction catalysts based on precious metals such as platinum or its alloys are routinely used in fuel cells because of their high activity. Carbon-supported materials containing metals such as iron or cobalt as well as nitrogen impurities have been proposed to increase scalability and reduce costs, but these alternatives usually suffer from low activity and/or gradual deactivation during use. Here, we show that few-walled carbon nanotubes, following outer wall exfoliation via oxidation and high-temperature reaction with ammonia, can act as an oxygen reduction reaction electrocatalyst in both acidic and alkaline solutions. Under a unique oxidation condition, the outer walls of the few-walled carbon nanotubes are partially unzipped, creating nanoscale sheets of graphene attached to the inner tubes. The graphene sheets contain extremely small amounts of irons originated from nanotube growth seeds, and nitrogen impurities, which facilitate the formation of catalytic sites and boost the activity of the catalyst, as revealed by atomic-scale microscopy and electron energy loss spectroscopy. Whereas the graphene sheets formed from the unzipped part of the outer wall of the nanotubes are responsible for the catalytic activity, the inner walls remain intact and retain their electrical conductivity, which facilitates charge transport during electrocatalysis.
1,471 citations
TL;DR: In this paper, the photocatalytic performance of the reduced graphene oxide (hGO)-TNT composites was evaluated for the photodegradation of malachite green using X-ray diffraction (XRD), Raman, FTIR, and XPS analysis.
Abstract: In this study, TiO2 nanotube (TNT)/reduced graphene oxide (hGO) composites were prepared by an alkaline hydrothermal process. This was achieved by decorating graphene oxide (GO) layers with commercially available TiO2 nanoparticles (P90) followed by hydrothermal synthesis, which converts the TiO2 nanoparticles to small diameter (∼9 nm) TNTs on the hGO surface. The alkaline medium used to synthesize the TNTs simultaneously converts GO to deoxygenated graphene oxide (hGO). Compared to GO, the hGO has a ∼70% reduction of oxygenated species after alkaline hydrothermal treatment. The graphene nature of hGO in the composites was confirmed by X-ray diffraction (XRD), Raman, FTIR, and X-ray photoelectron spectroscopy (XPS) analysis. The photocatalytic performance of the hGO-TNT composites was evaluated for the photodegradation of malachite green. It was found that the ratio of hGO to TNT in the composites significantly affects the photocatalytic activity. Higher amounts of hGO in hGO-TNT composites showed lower p...
868 citations
TL;DR: Ferroferric oxide (Fe(3)O(4)) was selected as the phase in multiwalled carbon nanotube (MWCNT)-based composites for enhancing magnetic properties to obtain improved electromagnetic attenuation and exhibited enhanced magnetic properties coupled with increased dielectric properties.
Abstract: Light-weight nanocomposites filled with carbon nanotubes (CNTs) are developed for their significant potentials in electromagnetic shielding and attenuation for wide applications in electronics, communication devices, and specific parts in aircrafts and vehicles. Specifically, the introduction of a second phase into/onto CNTs for achieving CNT-based heterostructures has been widely pursued due to the enhancement in either dielectric loss or magnetic loss. In this work, ferroferric oxide (Fe(3)O(4)) was selected as the phase in multiwalled carbon nanotube (MWCNT)-based composites for enhancing magnetic properties to obtain improved electromagnetic attenuation. A direct comparison between the two-phase heterostructures (Fe(3)O(4)/MWCNTs) and polyaniline (PANI) coated Fe(3)O(4)/MWCNTs, namely, three-phase heterostructures (PANI/Fe(3)O(4)/MWCNTs), was made to investigate the interface influences of Fe(3)O(4) and PANI on the complex permittivity and permeability separately. Compared to PANI/Fe(3)O(4)/MWCNTs, Fe(3)O(4)/MWCNTs exhibited enhanced magnetic properties coupled with increased dielectric properties. Interfaces between MWCNTs and heterostructures were found to play a role in the corresponding properties. The evaluation of microwave absorption of their wax composites was carried out, and the comparison between Fe(3)O(4)/MWCNTs and PANI/Fe(3)O(4)/MWCNTs with respect to highly efficient microwave absorption and effective absorption bandwidth was discussed.
798 citations
TL;DR: A conductive multiwalled carbon nanotube (MWCNT) interlayer acting as a pseudo-upper current collector not only reduces the charge transfer resistance of sulfur cathodes significantly, but also localizes and retains the dissolved active material during cycling.
696 citations
TL;DR: This first demonstration of CNT transistors with channel lengths down to 9 nm shows substantially better scaling behavior than theoretically expected and should ignite exciting new research into improving the purity and placement of nanotubes, as well as optimizing CNT transistor structure and integration.
Abstract: Although carbon nanotube (CNT) transistors have been promoted for years as a replacement for silicon technology, there is limited theoretical work and no experimental reports on how nanotubes will perform at sub-10 nm channel lengths. In this manuscript, we demonstrate the first sub-10 nm CNT transistor, which is shown to outperform the best competing silicon devices with more than four times the diameter-normalized current density (2.41 mA/μm) at a low operating voltage of 0.5 V. The nanotube transistor exhibits an impressively small inverse subthreshold slope of 94 mV/decade-nearly half of the value expected from a previous theoretical study. Numerical simulations show the critical role of the metal-CNT contacts in determining the performance of sub-10 nm channel length transistors, signifying the need for more accurate theoretical modeling of transport between the metal and nanotube. The superior low-voltage performance of the sub-10 nm CNT transistor proves the viability of nanotubes for consideration in future aggressively scaled transistor technologies.
681 citations
TL;DR: The synergy between nanotubular structures of TiO(2) and uniformly dispersed Pd QDs on TiO.(2) facilitated the charge transfer of photoinduced electrons from TiO (2) nanotubes to PD QDs and the high activity of PdQDs catalytic center, thereby leading to high-efficiency photoelectrocatalytic hydrogen generation.
Abstract: TiO(2) nanotube arrays (TNTAs) sensitized by palladium quantum dots (Pd QDs) exhibit highly efficient photoelectrocatalytic hydrogen generation. Vertically oriented TNTAs were prepared by a three-step electrochemical anodization. Subsequently, Pd QDs with uniform size and narrow size distribution were formed on TiO(2) nanotubes by a modified hydrothermal reaction (i.e., yielding nanocomposites of Pd QDs deposited on TNTAs, Pd@TNTAs). By exploiting Pd@TNTA nanocomposites as both photoanode and cathode, a substantially increased photon-to-current conversion efficiency of nearly 100% at λ = 330 nm and a greatly promoted photocatalytic hydrogen production rate of 592 μmol·h(-1)·cm(-2) under 320 mW·cm(-2) irradiation were achieved. The synergy between nanotubular structures of TiO(2) and uniformly dispersed Pd QDs on TiO(2) facilitated the charge transfer of photoinduced electrons from TiO(2) nanotubes to Pd QDs and the high activity of Pd QDs catalytic center, thereby leading to high-efficiency photoelectrocatalytic hydrogen generation.
541 citations
TL;DR: Using aberration-corrected scanning transmission electron microscopy, the covalent transformation of sp(2) carbon between the planar graphene and the single-walled carbon nanotubes at the atomic resolution level is observed, providing a new benchmark for understanding the three-dimensional graphene/single-walling carbon Nanotube-conjoined materials.
Abstract: Graphene and single-walled carbon nanotubes have high electrical conductivities and large specific surface areas. Here, these properties are extended into three dimensions by producing a seamless carbon nanotube graphene hybrid material.
491 citations
TL;DR: In this paper, an actual understanding of the relation between processing conditions, state of CNT dispersion and structure of the filler network, and the resulting electrical, melt rheological and mechanical properties is presented.
466 citations
TL;DR: A highly elastic strain gauge based on capacitive sensing of parallel, carbon nanotube-based percolation electrodes separated by a dielectric elastomer that is reliable, linear performance over thousands of cycles at up to 100% strain with less than 3% variability and the highest reported gauge factor for a device of this class.
Abstract: We present a highly elastic strain gauge based on capacitive sensing of parallel, carbon nanotube-based percolation electrodes separated by a dielectric elastomer. The fabrication, relying on vacuum filtration of single-walled carbon nanotubes and hydrophobic patterning of silicone, is both rapid and inexpensive. We demonstrate reliable, linear performance over thousands of cycles at up to 100% strain with less than 3% variability and the highest reported gauge factor for a device of this class (0.99). We further demonstrate use of this sensor in a robotics context to transduce joint angles.
430 citations
TL;DR: Simulations show that the bandwidth of this branched intracellular nanotube FET (BIT-FET) is high enough for it to record fast action potentials even when the nanot tube diameter is decreased to 3 nm, a length scale which is well below that accessible with other methods.
Abstract: A silicon nanowire field-effect transistor coupled to the interior of a cell by means of a hollow silicon dioxide nanotube can detect changes in the electric potential of the intracellular fluid.
426 citations
TL;DR: The high specific capacitance and charge-discharge rates offered by such MnO(2)/Mn/Mn O(2) sandwich-like nanotube arrays make them promising candidates for supercapacitor electrodes, combining high-energy densities with high levels of power delivery.
Abstract: We demonstrate the design and fabrication of novel nanoarchitectures of MnO2/Mn/MnO2 sandwich-like nanotube arrays for supercapacitors. The crystalline metal Mn layers in the MnO2/Mn/MnO2 sandwich-like nanotubes uniquely serve as highly conductive cores to support the redox active two-double MnO2 shells with a highly electrolytic accessible surface area and provide reliable electrical connections to MnO2 shells. The maximum specific capacitances of 937 F/g at a scan rate of 5 mV/s by cyclic voltammetry (CV) and 955 F/g at a current density of 1.5 A/g by chronopotentiometry were achieved for the MnO2/Mn/MnO2 sandwich-like nanotube arrays in solution of 1.0 M Na2SO4. The hybrid MnO2/Mn/MnO2 sandwich-like nanotube arrays exhibited an excellent rate capability with a high specific energy of 45 Wh/kg and specific power of 23 kW/kg and excellent long-term cycling stability (less 5% loss of the maximum specific capacitance after 3000 cycles). The high specific capacitance and charge–discharge rates offered by su...
TL;DR: Porous Pt-Ni-P composite nanotube arrays (NTAs) on a conductive substrate in good solid contact are successfully synthesized via template-assisted electrodeposition and show high electrochemical activity and long-term stability for methanol electrooxidation.
Abstract: Porous Pt-Ni-P composite nanotube arrays (NTAs) on a conductive substrate in good solid contact are successfully synthesized via template-assisted electrodeposition and show high electrochemical activity and long-term stability for methanol electrooxidation. Hollow nanotubular structures, porous nanostructures, and synergistic electronic effects of various elements contribute to the high electrocatalytic performance of porous Pt-Ni-P composite NTA electrocatalysts.
TL;DR: A multifunctional phase change composite in which the energy storage can be driven by small voltages or light illumination with high electro- to-heat or photo-to-thermal storage efficiencies and results in enhanced phase change enthalpy and thermal conductivity compared to pure paraffin wax.
Abstract: Organic phase change materials are usually insulating in nature, and they are unlikely to directly trigger latent heat storage through an electrical way. Here we report a multifunctional phase change composite in which the energy storage can be driven by small voltages (e.g., 1.5 V) or light illumination with high electro-to-heat or photo-to-thermal storage efficiencies (40% to 60%). The composite is composed of paraffin wax infiltrated into a porous, deformable carbon nanotube sponge; the latter not only acts as a flexible encapsulation scaffold for wax but also maintains a highly conductive network during the phase change process (for both solid and liquid states). Uniform interpenetration between the nanotube network and paraffin wax with high affinity results in enhanced phase change enthalpy and thermal conductivity compared to pure paraffin wax. Our phase change composite can store energy in practical ways such as by sunlight absorption or under voltages applied by conventional lithium-ion batteries.
TL;DR: This work pioneers the bulk synthesis of 3D macroscale nanotube elastic solids directly via a boron-doping strategy during chemical vapour deposition, which influences the formation of atomic-scale “elbow” junctions and nanotubes covalent interconnections.
Abstract: The establishment of covalent junctions between carbon nanotubes (CNTs) and the modification of their straight tubular morphology are two strategies needed to successfully synthesize nanotube-based three-dimensional (3D) frameworks exhibiting superior material properties. Engineering such 3D structures in scalable synthetic processes still remains a challenge. This work pioneers the bulk synthesis of 3D macroscale nanotube elastic solids directly via a boron-doping strategy during chemical vapour deposition, which influences the formation of atomic-scale "elbowg" junctions and nanotube covalent interconnections. Detailed elemental analysis revealed that the "elbowg" junctions are preferred sites for excess boron atoms, indicating the role of boron and curvature in the junction formation mechanism, in agreement with our first principle theoretical calculations. Exploiting this materialĝ€™s ultra-light weight, super-hydrophobicity, high porosity, thermal stability, and mechanical flexibility, the strongly oleophilic sponge-like solids are demonstrated as unique reusable sorbent scaffolds able to efficiently remove oil from contaminated seawater even after repeated use.
TL;DR: In this paper, a self-assembled cylindrical graphene-carbon nanotube (G-CNT) hybrid was used to remove methylene blue (MB) from aqueous solution.
TL;DR: In this paper, the morphology of the hierarchical top-layer/bottom-tube TiO2 (TiO2 NTs) can be finely tuned between nanoring/nanotube, nanopore/notube and nanohole-nanocave/nanoxube morphologies to optimize the photocurrent density and photoconversion efficiency.
Abstract: In this paper, we show that by varying the voltages during two-step anodization the morphology of the hierarchical top-layer/bottom-tube TiO2 (TiO2 NTs) can be finely tuned between nanoring/nanotube, nanopore/nanotube, and nanohole–nanocave/nanotube morphologies. This allows us to optimize the photoelectrochemical (PEC) water splitting performance on the hierarchical TiO2 NTs. The optimized photocurrent density and photoconversion efficiency in this study, occurring on the nanopore/nanotube TiO2 NTs, were 1.59 mA cm−2 at 1.23 V vs. RHE and 0.84% respectively, which are the highest values ever reported on pristine TiO2 materials under illumination of AM 1.5G. Our findings contribute to further improvement of the energy conversion efficiency of TiO2-based devices.
TL;DR: This work attained a highly ordered ZnO/TNTs hybrid nanostructure and found that the hybrid photocatalyst demonstrated excellent photostability, which could present a straightforward paradigm for preparation of hierarchical semiconductor/1-D semiconductor heterostructures.
Abstract: In recent years, strenuous efforts have been devoted to exploring ZnO functionalized TiO(2) nanotube arrays (ZnO/TNTs) nanocomposites; however, there is still a paucity of reports on the construction of well-defined ZnO/TNTs heterostructure via efficient and easily accessible approach. In this work, drawing on a two-step anodization combined pyrolysis strategy, we attained a highly ordered ZnO/TNTs hybrid nanostructure. Combined with a collection of characterizations including X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), diffusion reflectance spectrum (DRS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), we found that, in this coupling, in situ formed ZnO phases were uniformly grafted to TNTs framework giving rise to hybrid nanostructure, which is ascribed to cooperative interfacial interaction between polar TiO(2) layer and ZnO precursor. The underlying interaction leading to judicious combination of TNTs and ZnO was unveiled by Fourier transformed infrared spectrum (FTIR) and XPS. Alternatively, it has been shown that ZnO nanocrystals distributed on the TNTs could serve as favorable hole channels and receptors for efficient separation of photoexcited charge carriers, which results in significantly enhanced photocatalytic performances of ZnO/TNTs heterostructure in comparison with pure TNTs, ZnO film, and P25 particulate film. Furthermore, it is found that the hybrid photocatalyst demonstrated excellent photostability. It is hoped that our work could present a straightforward paradigm for preparation of hierarchical semiconductor/1-D semiconductor heterostructures.
TL;DR: A short [5,5] CNT has now been synthesized by stepwise chemical methods, isolated, purified, crystallized, and fully characterized by NMR spectroscopy, UV-vis absorption spectroscopic, high resolution mass spectrometry, and X-ray crystallography.
Abstract: The inaccessibility of uniform-diameter, single-chirality carbon nanotubes (CNTs) in pure form continues to thwart efforts by scientists to use these ultrathin materials in innovative applications that could revolutionize nanoscale electronics. Stimulated by the challenge to address this long-standing problem, we and other organic chemists have envisioned a new production strategy involving the controlled elongation of small hydrocarbon templates, such as hemispherical nanotube end-caps, prepared by bottom-up chemical synthesis; the diameter and rim structure encoded in the template would dictate the diameter and chirality of the resulting CNT. Toward that objective, a short [5,5] CNT has now been synthesized by stepwise chemical methods. This C50H10 geodesic polyarene has been isolated, purified, crystallized, and fully characterized by NMR spectroscopy, UV–vis absorption spectroscopy, high resolution mass spectrometry, and X-ray crystallography.
TL;DR: It is shown that TiO(2)-H nanowire-microspheres have Ti-H and O-H bonds on their surface and exhibit improved visible-light absorption and highly enhanced photocatalytic activity.
TL;DR: In this article, a humidity sensor on cellulose paper is demonstrated using single-walled carbon nanotubes functionalized with carboxylic acid, which exhibits linear behavior up to a relative humidity of 75% with good repeatability and low hysteresis.
Abstract: A humidity sensor on cellulose paper is demonstrated using single-walled carbon nanotubes functionalized with carboxylic acid. The conductance shift of the nanotube network entangled on the microfibril cellulose is utilized for the humidity sensing. Compared to the control sensor made on a glass substrate, the cellulose-mediated charge transport on the paper substrate enhances the sensitivity. The sensor response exhibits linear behavior up to a relative humidity of 75% with good repeatability and low hysteresis. A simple circuit model is used to explain the sensor results. This approach is a step toward future paper electronics for low-cost disposable applications.
TL;DR: In this article, a novel way of synthesizing graphene-carbon nanotube hybrid nanostructure as an anode for lithium ion batteries was proposed, which was obtained by homogeneous mixing of chemically modified graphene and carbon nanotubes constituents.
Abstract: We report a novel way of synthesizing graphene-carbon nanotube hybrid nanostructure as an anode for lithium (Li) ion batteries. For this, graphene was prepared by the solar exfoliation of graphite oxide, while multiwalled carbon nanotubes (MWNTs) were prepared by the chemical vapor deposition method. The graphene–MWNT hybrid nanostructure was synthesized by first modifying graphene surface using a cationic polyelectrolyte and MWNT surface with acid functionalization. The hybrid structure was obtained by homogeneous mixing of chemically modified graphene and MWNT constituents. This hybrid nanostructure exhibits higher specific capacity and cyclic stability. The strengthened electrostatic interaction between the positively charged surface of graphene sheets and the negatively charged surface of MWNTs prevents the restacking of graphene sheets that provides a highly accessible area and short diffusion path length for Li-ions. The higher electrical conductivity of MWNTs promotes an easier movement of the electrons within the electrode. The present synthesis scheme recommends a new pathway for large-scale production of novel hybrid carbon nanomaterials for energy storage applications and underlines the importance of preparation routes followed for synthesizing nanomaterials.
TL;DR: The use of a catecholic anchor (Dopa) for selective modification of the inner surface of an halloysite clay nanotube and surface-initiated atom transfer radical polymerization (SI-ATRP) was performed.
Abstract: We demonstrate the use of a catecholic anchor (Dopa) for selective modification of the inner surface of an halloysite clay nanotube. Aqueous Dopa binds to alumina at the tube lumen and does not bind the silica surface under the same conditions. Selectivity of surface modification was evidenced using X-ray photoelectron spectroscopy (XPS) and 13C solid state NMR spectroscopy. Surface-initiated atom transfer radical polymerization (SI-ATRP) was performed through selectively adsorbed Dopa to graft a layer of polymer brush into the nanotube lumen.
TL;DR: This tutorial review presents an overview of nanotubes derived from this class of cyclic peptides, and highlights the recent expansion of the nanotube toolbox through conjugation of (macro)molecules to the cycling peptides.
Abstract: β-Sheet forming self assembling cyclic peptides offer a versatile scaffold for the construction and control of hydrogen-bonded nanotube assemblies. These structures have major advantages over other nanoscale tubular structures, including sub-nanometer control over the internal diameter, and the ability to control internal and external chemical functionality. This Tutorial Review presents an overview of nanotubes derived from this class of cyclic peptides. The design rationale for functional nanotubes based on cyclic peptide ring size and chemical functionality is discussed. Additionally, we highlight the recent expansion of the nanotube toolbox through conjugation of (macro)molecules to the cyclic peptides. These provide additional functionality and control nanotube dimensions that could potentially prove beneficial in future applications.
TL;DR: A group IVA based nanotube heterostructure array, consisting of a high-capacity Si inner layer and a highly conductive Ge outer layer, to yield both favorable mechanics and kinetics in battery applications.
Abstract: Problems related to tremendous volume changes associated with cycling and the low electron conductivity and ion diffusivity of Si represent major obstacles to its use in high-capacity anodes for lithium ion batteries. We have developed a group IVA based nanotube heterostructure array, consisting of a high-capacity Si inner layer and a highly conductive Ge outer layer, to yield both favorable mechanics and kinetics in battery applications. This type of Si/Ge double-layered nanotube array electrode exhibits improved electrochemical performances over the analogous homogeneous Si system, including stable capacity retention (85% after 50 cycles) and doubled capacity at a 3C rate. These results stem from reduced maximum hoop strain in the nanotubes, supported by theoretical mechanics modeling, and lowered activation energy barrier for Li diffusion. This electrode technology creates opportunities in the development of group IVA nanotube heterostructures for next generation lithium ion batteries.
TL;DR: The postmodification of the MONT can be easily operated by unmarking the imidazolium moieties in the channel walls, which was conducted as a highly active heterogeneous catalyst for Suzuki-Miyaura and Heck coupling reactions, hydrogenation of olefins and nitrobenzene, while the constituent elements are less efficient for these reactions under the same conditions.
Abstract: A metal–organic nanotube (MONT) was synthesized by linking up the bent organic ligands and the tetra-coordinated zinc cations under mild conditions. Structural analysis revealed that the MONT has a very large exterior wall diameter of 4.91 nm and an interior channel diameter of 3.32 nm. Interlocking of the nanotubes gives rise to a 3D chiral framework containing 1D helical cylindered channels with diameter of 2.0 nm. The MONT has very interesting property by synergizing the functionality of nanotubes, metal–organic frameworks (MOFs), and N-heterocyclic carbenes (NHCs). The dye adsorption experiments demonstrate that the channels of the MONTs are accessible to large reagents typically used for catalysis. The postmodification of the MONT can be easily operated by unmarking the imidazolium moieties in the channel walls, which was conducted as a highly active heterogeneous catalyst for Suzuki–Miyaura and Heck coupling reactions, hydrogenation of olefins and nitrobenzene, while the constituent elements are les...
TL;DR: In this paper, a new kind of porous beads was prepared by immobilizing halloysite nanotubes with alginate (Alg), and the as-prepared product was characterized by scanning electron microscope (SEM).
TL;DR: In this paper, the 3D graphene-CNT hybrid foams were used as novel 3D electrochemical electrodes for sensing applications, and they showed high sensitivity (∼470.7 mA M−1 cm−2) and low detection limit (∲20 nM with S/N ≈ 9.2) for dopamine detection.
Abstract: Three-dimensional (3D) graphene–carbon nanotube (CNT) hybrids are synthesized by two-step chemical vapor deposition (CVD) under atmospheric pressure. As revealed by scanning electron microscopy (SEM), the hybrid is a monolithic graphene foam with conformal coverage of a dense CNT mesh. We further demonstrate that the obtained graphene–CNT hybrid foams can be used as novel 3D electrochemical electrodes for sensing applications. Specifically, the 3D graphene–CNT electrodes exhibit a high sensitivity (∼470.7 mA M−1 cm−2) and low detection limit (∼20 nM with S/N ≈ 9.2) for dopamine detection. Modified with horseradish peroxidase and Nafion, the 3D hybrid electrodes are also used to detect H2O2 with a high sensitivity (137.9 mA M−1 cm−2), low detection limit (∼1 μM with S/N ≈ 17.4), and wide linear detection range (10 μM–1 mM).
TL;DR: This work has grown vertically aligned single-walled carbon nanotube forests with an area density of 1.5 × 10(13) cm(-2), the highest yet achieved, by reducing the average diameter of the nanotubes.
Abstract: We have grown vertically aligned single-walled carbon nanotube forests with an area density of 1.5 × 10(13) cm(-2), the highest yet achieved, by reducing the average diameter of the nanotubes. We use a nanolaminate Fe-Al(2)O(3) catalyst design consisting of three layers of Al(2)O(3), Fe, and Al(2)O(3), in which the lower Al(2)O(3) layer is densified by an oxygen plasma treatment to increase its diffusion barrier properties, to allow a thinner catalyst layer to be used. This high nanotube density is desirable for using carbon nanotubes as interconnects in integrated circuits.
TL;DR: It is found that electron-electron interactions shift the optical resonance energies by the same amount for both metallic and semiconducting nanotubes, and that this shift increases monotonically with nanotube diameter.
Abstract: The results of simultaneous measurements of the structure and optical properties of more than 200 single-walled carbon nanotubes are reported and included in an atlas that allows the chiral index of any single-walled nanotube to be determined from a measurement of its optical resonances, and vice versa.
TL;DR: In this article, five different structures, namely SWNT, DWNT, FWNT, and two different multiwalls were applied in order to investigate the dependence of carbon nanotube (CNT) structures in water-based nanofluid, as well as their dependence to temperature and time variation.