Methanol adsorption in carbon nanotubes

Burghaus, U.; Bye, D.; Cosert, K.; Goering, J.; Guerard, A.; Kadossov, E.; Lee, E.; Nadoyama, Y.; Richter, Norina A.; Schaefer, E.A.; Smith, Joshua R.; Ulness, Darin J.; Wymore, B.

doi:10.1016/j.cplett.2007.05.094

Cited by 33 publications

(18 citation statements)

References 24 publications

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“…Because of their large adsorptive capacity and high electron and thermal conductivity, CNTs have many potential applications as, for example, heterogeneous catalysts, 1−3 storage media, 4,5 and gas sensors, 6 for which understanding of the gas−nanotube interactions is rather important. Adsorption isotherm, 7,8 infrared (IR) spectroscopy, 9,10 temperature programmed desorption (TPD), 11,12 and Raman spectroscopy 13,14 have been widely employed to study the adsorption of the gas molecules in CNTs. As compared to these methods, nuclear magnetic resonance (NMR) is a nondestructive technique and can provide bulk information on the adsorption sites, mechanisms, and strengths of adsorbates on nanotubes.…”

Section: Introductionmentioning

confidence: 99%

NMR Study of Preferential Endohedral Adsorption of Methanol in Multiwalled Carbon Nanotubes

et al. 2012

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Adsorption of 13 C-enriched methanol in multiwalled carbon nanotubes (MWNTs) was systematically studied under well-controlled environment by 13 C MAS NMR. The results of variable-pressure experiments indicate that the endohedral adsorption of methanol in carbon nanotubes (CNTs) is preferential over the exohedral adsorption. The exohedral adsorption does not occur until the endohedral adsorption saturates. The 13 C chemical shift of endohedral methanol exhibits a large upfield shift due to the strong spatial diamagnetic shielding effect induced by the delocalized electrons of nanotubes under the influence of external magnetic field. The exohedral methanol is also shielded, but to a lesser extent. DFT calculations support these experimental results. The 13 C spin−lattice relaxation times, T 1 , of endohedral and exohedral methanol were also measured, and they have different vapor pressure dependence at room temperature. Furthermore, variable-temperature experiments suggest that methanol molecules inside CNTs may form a layered structure at low temperature with one layer close to the wall and the second layer near the center of the nanotubes.

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Section: Introductionmentioning

confidence: 99%

NMR Study of Preferential Endohedral Adsorption of Methanol in Multiwalled Carbon Nanotubes

et al. 2012

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“…The majority of classical MD studies utilizing standard force fields (FFs), e.g., CHARMM, 44 AMBER, 45 GROMOS 46 have employed either strong positional restraints or constraints when simulating SWCNTs. 19,26,27,[36][37][38][39][40][41][42] Thus, the tube models are a representation of a rigid hydrophobic/aromatic pore. Similarly, in our work, the tubes are rigid (see Fig.…”

Section: A Molecular Dynamics Simulationsmentioning

confidence: 99%

“…[14][15][16][17] Among many potential applications of nanofluidic devices, the partitioning/filtration of polar molecules, i.e., alcohols from the aqueous solution is of vital importance in industry, as these species are very hard to separate due to their hydrophilic nature. 18,19 Moreover, many water pollutants possess phenolic moieties with an ongoing concern on their e↵ects on the environment and human health. 20 In fact, many e↵orts are currently being carried out to develop cheap alcohol nano-filtering devices.…”

Section: Introductionmentioning

confidence: 99%

“…23,[31][32][33][34][35] Meanwhile, the interaction between CNTs and other solvents has been scarcely explored and only recently, reports of alcohol separation by CNTs have appeared in the literature. 19,[36][37][38][39][40][41][42][43] Small alcohols such as ethanol and methanol share common features with water, having a polar OH group and presenting a dipole; therefore, it is not strange that carbon-nanotubes do partition alcohols from an aqueous phase given the common features shared with water, plus the additional hydrophobicity provided by the carbon backbone. Consequently, in this work, MD simulations of SWCNT ((6,6), (7,7), and (8,8)) assisted partitioning of ethanol and methanol were performed; a fully characterization based on dynamical (rotational relaxation, di↵usional, mean residence times) and structural properties (interaction energies, dipolar alignment, and displacement correlations) was carried out and compared with simulations of water and methane infiltration, taken as examples of the limiting conditions of small fully polar and hydrophobic molecules, respectively.…”

Section: Introductionmentioning

confidence: 99%

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From dimers to collective dipoles: Structure and dynamics of methanol/ethanol partition by narrow carbon nanotubes

Gárate

Pérez-Acle

2016

The Journal of Chemical Physics

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Alcohol partitioning by narrow single-walled carbon nanotubes (SWCNTs) holds the promise for the development of novel nanodevices for diverse applications. Consequently, in this work, the partition of small alcohols by narrow tubes was kinetically and structurally quantified via molecular dynamics simulations. Alcohol partitioning is a fast process in the order of 10 ns for diluted solutions but the axial-diffusivity within SWCNT is greatly diminished being two to three orders of magnitude lower with respect to bulk conditions. Structurally, alcohols form a single-file conformation under confinement and more interestingly, they exhibit a pore-width dependent transition from dipole dimers to a single collective dipole, for both methanol and ethanol. Energetic analyses demonstrate that this transition is the result of a detailed balance between dispersion and electrostatics interactions, with the latter being more pronounced for collective dipoles. This transition fully modifies the reorientational dynamics of the loaded particles, generating stable collective dipoles that could find usage in signal-amplification devices. Overall, the results herein have shown distinct physico-chemical features of confined alcohols and are a further step towards the understanding and development of novel nanofluidics within SWCNTs.

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“…[20] the adsorption of methanol on very small flakes of graphene-benzene and coronene-was also calculated by the higher accuracy correlation method second-order Møller-Plesset perturbation theory (MP2). Desorption energies from highly oriented pyrolytic graphite (HOPG) or from various sizes CNTs have also been measured previously in a number of desorption experiments [22,23].…”

Section: Introductionmentioning

confidence: 99%

First-principle study of methanol adsorption on Ni (Pd)-decorated graphene

Peyghan

Moradi

2014

J IRAN CHEM SOC

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have been investigated extensively. CNTs have recently emerged as a promising substitute for materials of different properties and they have various applications in hydrogen storages, gas sensors, textiles, and many more [2][3][4][5]. In addition CNTs, graphene has attracted increasing scientific and technological interests because of its special electronic and mechanical features [6,7]. In graphene research, molecular interaction (e.g., of NO 2 , NH 3 , and so forth) with the graphene surface is a subfield of considerable interest because of potential applications such as chemical sensors, gas storages, and electronic devices [8,9]. The reactivity of these nanotubes is often adjusted by doping or decoration with other elements. It is important to understand and be able to quantify the modification of the surface properties by the addition of such elements. In recent years, metal dispersed carbon nanostructures have been approved to be efficient for gas storage because of their light weight, diversity in structures, large surface area, and interesting hydrogen adsorption properties [10][11][12][13]. Most of the results suggest that the adsorption energy of the gas molecule on decorated carbon-based systems increases compared with their pristine ones.Within the last years, there has been an increased interest in direct methanol fuel cells (DMFCs) as they are a promising power source for micro and portable applications, since methanol is a liquid at room temperature, has high energy density, is easy to handle, and easy to store and distribute. However, a number of issues need to be solved before DMFC can be commercially viable. These include the slow anode kinetics arising from a multi-step fuel oxidation process at the anode which results in higher anodic over potentials, and the fuel crossover from anode to cathode. The crossover not only lowers the fuel utilization, but also degrades the cathode performance and generates extra heat. Therefore, optimizing the design and the Abstract Ab initio first-principle calculations, including dispersion correction, were carried out to investigate Ni (Pd)-decorated graphene for its application as methanol storage materials. Structural optimization showed that the CH 3 OH molecule is physisorbed on the pristine sheet via van der Waals forces with the adsorption energy of −11.7 kcal/mol. It was found that unlike the pristine graphene, metal-decorated sheet can effectively interact with the CH 3 OH molecule, so that single Ni and Pd atoms prefer to bind strongly on the top of the bridge site of graphene, and each metal atom bound on the sheet may adsorb up to four CH 3 OHs. Furthermore, no bond dissociation was observed for the adsorption of CH 3 OH on Ni (Pd)-decorated graphene, which means that decorated sheet can act as a storage device for methanol safety storage. The results also indicated that decoration of the Ni and Pd atoms on the surface of graphene induces some changes in the electronic properties of the sheet and its E g remained unchanged after the adsorption of CH...

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Methanol adsorption in carbon nanotubes

Cited by 33 publications

References 24 publications

NMR Study of Preferential Endohedral Adsorption of Methanol in Multiwalled Carbon Nanotubes

NMR Study of Preferential Endohedral Adsorption of Methanol in Multiwalled Carbon Nanotubes

From dimers to collective dipoles: Structure and dynamics of methanol/ethanol partition by narrow carbon nanotubes

First-principle study of methanol adsorption on Ni (Pd)-decorated graphene

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