共查询到20条相似文献,搜索用时 15 毫秒
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Shulai Lei Beate Paulus Shujuan Li Burkhard Schmidt 《Journal of computational chemistry》2016,37(14):1313-1320
The curvature dependence of the physisorption properties of a water molecule inside and outside an armchair carbon nanotube (CNT) is investigated by an incremental density‐fitting local coupled cluster treatment with single and double excitations and perturbative triples (DF‐LCCSD(T)) study. Our results show that a water molecule outside and inside (n, n) CNTs (n = 4, 5, 6, 7, 8, 10) is stabilized by electron correlation. The adsorption energy of water inside CNTs decreases quickly with the decrease of curvature (increase of radius) and the configuration with the oxygen pointing toward the CNT wall is the most stable one. However, when the water molecule is adsorbed outside the CNT, the adsorption energy varies only slightly with the curvature and the configuration with hydrogens pointing toward the CNT wall is the most stable one. We also use the DF‐LCCSD(T) results to parameterize Lennard‐Jones (LJ) force fields for the interaction of water both with the inner and outer sides of CNTs and with graphene representing the zero curvature limit. It is not possible to reproduce all DF‐LCCSD(T) results for water inside and outside CNTs of different curvature by a single set of LJ parameters, but two sets have to be used instead. Each of the two resulting sets can reproduce three out of four minima of the effective potential curves reasonably well. These LJ models are then used to calculate the water adsorption energies of larger CNTs, approaching the graphene limit, thus bridging the gap between CNTs of increasing radius and flat graphene sheets. © 2016 Wiley Periodicals, Inc. 相似文献
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Phenol adsorption on closed carbon nanotubes 总被引:1,自引:0,他引:1
Pacholczyk A Terzyk AP Wiśniewski M Gauden PA Wesołowski RP Furmaniak S Szcześ A Chibowski E Kruszka B 《Journal of colloid and interface science》2011,361(1):288-292
We present the results of systematic studies of phenol adsorption on closed commercially available, unmodified carbon nanotubes. Phenol adsorption is determined by the value of tube-specific surface area, the presence of small amount of surface groups influence adsorption only in very small amount. Phenol can be applied as a probe molecule for comparative analysis of tube surface areas. Tube curvature influences adsorption from solution, i.e., we observe increasing adsorption energy (and slower desorption process) with the decrease in tube curvature. This is in full accordance with molecular simulation results. 相似文献
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The properties and applications of CNT have been studied extensively since Iijima discovered them in 1991[1,2]. They have exceptional mechanical properties and unique electrical property, highly chemical stability and large specific surface area. Thus far, they have widely potential applications in many fields. They can be used as reinforcing materials in composites[3], field emissions[4], hydrogen storage[5], nanoelectronic components[6], catalyst supports[7], adsorption material and so on.… 相似文献
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《Comptes Rendus Chimie》2003,6(5-6):597-602
Self-assembly and morphological organization of various fulleropyrrolidine derivatives affords different and individual supramolecular architectures. Nanospheres, tubules and bundles of nanorods are formed depending on the nature of the added group in the fullerene unit. The current work represents, in the nanometer scale, a novel connection between spherical-shaped fullerene-based materials and fibrous-structurally nanotubes. We also report on the organic functionalization of carbon nanotubes via 1,3-dipolar cycloaddition of azomethine ylides, which results in solubilization of the functionalized nanotubes in most common organic solvents. To cite this article: D. Tasis et al., C. R. Chimie 6 (2003). 相似文献
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Simulation of adsorption of DNA on carbon nanotubes 总被引:2,自引:0,他引:2
We report molecular dynamics simulations of DNA adsorption on a single-walled carbon nanotube (SWNT) in an aqueous environment. We have modeled a DNA segment with 12 base pairs (Dickerson dodecamer) and a (8,8) SWNT in water, with counterions to maintain total charge neutrality. Simulations show that DNA binds to the external surface of an uncharged or positively charged SWNT on a time scale of a few hundred picoseconds. The hydrophobic end groups of DNA are attracted to the hydrophobic SWNT surface of uncharged SWNTs, while the hydrophilic backbone of DNA does not bind to the uncharged SWNT. The binding mode of DNA to charged SWNTs is qualitatively different from uncharged SWNTs. The phosphodiester groups of the DNA backbone are attracted to a positively charged SWNT surface while DNA does not adsorb on negatively charged SWNTs. There is no evidence for canonical double-stranded DNA wrapping around either charged or uncharged SWNTs on the very short time scales of the simulations. The adsorption process appears to have negligible effect on the internal stacking structure of the DNA molecule but significantly affects the A to B form conversion of A-DNA. The adsorption of A-DNA onto an uncharged SWNT inhibits the complete relaxation of A-DNA to B-DNA within the time scale of the simulations. In contrast, binding of the A-DNA onto a positively charged SWNT may promote slightly the A to B conversion. 相似文献
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I. G. Sidorenko O. V. Markitan N. N. Vlasova G. M. Zagorovskii V. V. Lobanov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(6):1002-1005
The adsorption of phenylethylamine, tryptamine, and tyramine on carbon nanotubes from aqueous solutions (pH 7.4) was studied
depending on time and sorbate concentration. The suggestion was made that their interaction with electrodes was determined
by electrostatic attraction between protonated amino groups and oxygen-containing functional groups of the surface of carbon.
An increase in the adsorption of biological amines was caused by the interaction of the π systems of their aromatic rings with carbon surface hexagons. The adsorption of biogenic amines on carbon nanotubes was necessary
for their possible electrooxidation and analytic determination by electrochemical methods with the use of carbon electrodes.
Original Russian Text ? I.G. Sidorenko, O.V. Markitan, N.N. Vlasova, G.M. Zagorovskii, V.V. Lobanov, 2009, published in Zhurnal
Fizicheskoi Khimii, 2009, Vol. 83, No. 6, pp. 1139–1142. 相似文献
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The potential energies of interaction between carbon nanotubes and internal fullerenes of spherical and ellipsoidal shape, as well as between nanotubes in multi-walled nanotubes were calculated using the Lennard–Jones (LJ) potential for carbon–carbon interactions. The optimum and maximum size of internal fullerenes and multi-walled nanotubes are determined as a function of the external nanotube radius. It was found that at the potential energy minimum, the van der Waals distance is close to that in graphite for all studied cases. The calculated results agree with available experimental observations and could be used as a guide for future experiments. 相似文献
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Recently there has been lot of interest in the development of hydrogen storage in various systems for the large-scale application
of fuel cells, mobiles and for automotive uses. Hectic materials research is going on throughout the world with various adsorption
mechanisms to increase the storage capacity. It was observed that physisorption proves to be an effective way for this purpose.
Some of the materials in this race include graphite, zeolite, carbon fibers and nanotubes. Among all these, the versatile
material carbon nanotube (CNT) has a number of favorable points like porous nature, high surface area, hollowness, high stability
and light weight, which facilitate the hydrogen adsorption in both outer and inner portions. In this work we have considered
armchair (5,5), zig zag (10,0) and chiral tubes (8,2) and (6,4) with and without structural defects to study the physisorption
of hydrogen on the surface of carbon nanotubes using DFT calculations. For two different H2 configurations, adsorption binding energies are estimated both for defect free and defected carbon nanotubes. We could observe
larger adsorption energies for the configuration in which the hydrogen molecular axis perpendicular to the hexagonal carbon
ring than for parallel to C–C bond configuration corresponding to the defect free nanotubes. For defected tubes the adsorption
energies are calculated for various configurations such as molecular axis perpendicular to a defect site octagon and parallel
to C–C bond of octagon and another case where the axis perpendicular to hexagon in defected tube. The adsorption binding energy
values are compared with defect free case. The results are discussed in detail for hydrogen storage applications. 相似文献
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Terzyk AP Pacholczyk A Wiśniewski M Gauden PA 《Journal of colloid and interface science》2012,376(1):209-216
We present the new results of systematic studies of paracetamol adsorption on closed, commercially available, unmodified carbon nanotubes. The results of thermal analysis, static adsorption measurements and the comparison with phenol adsorption data lead to suggestion that the formation of paracetamol nanoaggregates in the interstitial spaces between nanotubes occurs. This effect is also confirmed by the results of (performed in two ways) independent dynamic measurements and by molecular dynamics simulation technique. Next, we show that the behavior of adsorbed paracetamol during heating leads to the creation of a new drug delivery system. The properties of this system depend on the type of applied nanotubes and the parameters of the process called hot-melt drug deposition. Thus, we conclude that confined nanoaggregate formation, as well as hot-melt deposition should be promising effects in the preparation of highly effective, new drug delivery systems. 相似文献
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Mansoor H. Alshehri Barry J. Cox James M. Hill 《Journal of mathematical chemistry》2012,50(9):2512-2526
Deoxyribonucleic acid (DNA) is the genetic material for all living organisms, and as a nanostructure offers the means to create novel nanoscale devices. In this paper, we investigate the interaction of deoxyribonucleic acid inside single-walled carbon nanotubes. Using classical applied mathematical modeling, we derive explicit analytical expressions for the encapsulation of DNA inside single-walled carbon nanotubes. We adopt the 6–12 Lennard–Jones potential function together with the continuous approach to determine the preferred minimum energy position of the dsDNA molecule inside a single-walled carbon nanotube, so as to predict its location with reference to the cross-section of the carbon nanotube. An analytical expression is obtained in terms of hypergeometric functions which provides a computationally rapid procedure to determine critical numerical values. We observe that the double-strand DNA can be encapsulated inside a single-walled carbon nanotube with a radius larger than 12.30 ?, and we show that the optimal single-walled carbon nanotube to enclose a double-stranded DNA has radius 12.8 ?. 相似文献
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Müller EA 《The journal of physical chemistry. B》2008,112(30):8999-9005
Grand canonical Monte Carlo molecular simulations of the adsorption of three quadrupolar moleculesnitrogen (N(2)), carbon dioxide (CO(2)), and perfluoroethane (C(2)F(6))within single walled carbon nanotubes are reported. A unique slanted ordering is seen in the nanotubular systems (1-D geometry) which has not been reported before nor is present in slit nanopores (2-D geometry), and is due to the particular combination of steric effects and the unique anisotropic attraction experienced by these fluids. 相似文献
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V. V. Turov G. P. Prikhod’ko S. Ya. Brichka M. D. Tsapko 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(4):591-596
The joint adsorption of water and benzene on nanosized carbon tubes (NCTs) (with a specific surface area of 413 m2/g) synthesized by carbonizing methylene chloride in cylindrical pores of an Al2O3 matrix was studied. 1H NMR spectroscopy with layer-by-layer freezing of the liquid phase was used to characterize the water bound in pores at various contents of benzene and water. Due to its higher energy of interaction with carbon surfaces, benzene was demonstrated to decrease the energy of interaction of water with the surface of the NCT sample from 43 to 15 J/g. It was suggested that, in the presence of benzene, H-bonded water clusters only weakly bound to the surface are formed in the cylindrical cavities of the NCTs. 相似文献
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Picozzi S Santucci S Lozzi L Valentini L Delley B 《The Journal of chemical physics》2004,120(15):7147-7152
First-principles calculations within the density functional theory have been performed in order to investigate ozone adsorption on carbon nanotubes. Particular emphasis is placed on the effects of Stone-Wales-like defects on the structural and electronic properties of (i) ideal tubes and (ii) tubes in the presence of ozone. Our results show that structural deformations induced on the pure carbon nanotubes by Stone-Wales defects are similar, as expected, to those induced on graphite; for the (10,0) tube, the semiconducting character is kept, though with a small reduction of the band gap. As for the ozone adsorption, the process on ideal nanotubes is most likely physisorption, though slightly stronger if compared to other previously studied molecules and consistent with the strong oxydizing nature of O(3). However, when ozone adsorbs on Stone-Wales defects, a strong chemisorption occurs, leading to relevant structural relaxations and to the formation of a CO covalent bond; this is consistent with experimental observations of CO functional groups, as well as of the liberation of CO gas phase and of the formation of C vacancies, thus explaining the consumption of the nanotube film upon ozone exposure. 相似文献
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Gotovac S Hattori Y Noguchi D Miyamoto J Kanamaru M Utsumi S Kanoh H Kaneko K 《The journal of physical chemistry. B》2006,110(33):16219-16224
Phenanthrene was adsorbed from ethanol solution to the surface of single wall carbon nanotubes, which were previously physically and chemically characterized. Different anionic surfactants were added in the solutions to enhance the phenanthrene solubility and apparently have also improved the dispersion of two respective nanotube samples used. Adsorbed amount was determined through the concentration difference measured by UV-visible spectrophotometry. Results suggest that adsorption of phenanthrene is extremely improved in the case of nanotube purified with higher quality. These findings were confirmed by X-ray photoelectron spectroscopy. The influence of the surfactant on the adsorption kinetics of phenanthrene is suggested to be significant as well. 相似文献
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Possible ways for manipulating carbon nanotubes (CNTs) with cyclic supermolecules are studied using density functional theory. Electronic structure calculations with structure optimizations have been performed for the (4,4) and (8,0) single-walled carbon nanotubes (SWNTs) complexed with crown ethers as well as for the (4,0) SWNT with beta-cyclodextrin. A slight polarization of charge in both the nanotube and the supermolecule is observed upon rotaxane complexation, but the interaction is mainly repulsive, and the systems stay 2.8-3.5 A apart. The supermolecule does not affect the electronic band structure of the nanotube significantly within such a configuration. The situation differs noticeably for chemically cross-linked SWNTs and crown ethers, where a peak arises at the Fermi energy in the density of states. As a result, the band gap of semiconducting CNT(8,0) (0.5 eV) vanishes, and a new conduction channel opens for the metallic CNT(4,4). 相似文献