Density Functional Study of the Adsorption of Methanol and Its Derivatives on Boron Nitride Nanotubes (original) (raw)
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E-Journal of Chemistry, 2011
The density functional theory (DFT) has been used to simultaneously investigate physic/chemi-sorption properties of oxygen on the (5, 5) boron nitride nanotube (BNNT). Geometry optimizations were carried out at B3LYP/6-31G*level of theory using gaussian 98 suites of program. physisorption of O2outside the BNNT with a vertical orientation to the tube axis above a boron atom is the most stable state of physisorption and its binding energy is -0.775 kcal/mol. In the chemisorption of O2molecule, the most stable state is above two adjacent B and N atoms of a hexagon with a B-N bond length of 2.503 Å and the binding energy of adsorbed oxygen atoms -14.389 kcal/mol. Based on these results, We also provide the effects of O2adsorption on the electronic properties of BNNTs.
Crystals, 2016
The adsorption of H 2 O, NH 3 and HCOOH as polar molecules and C 6 H 6 and CH 4 as non-polar ones on a series of zigzag (6,0) single-walled boron nitride nanotubes (BNNTs) both being defect-free (P_BNNT) and containing defects at the nanotube walls has been studied by means of B3LYP-D2* periodic calculations. We focused on defects derived from monovacancies of B (N-rich_BNNT) and N (B-rich_BNNT) atoms and also on Stone-Wales defects (SW_BNNT). The adsorption of polar molecules with defective BNNTs is generally based on dative interactions and H-bonding, and their adsorption energies strongly depend on the type of BNNT. N-rich_BNNT is the most reactive nanotube towards adsorption of polar molecules, as in all cases deprotonation of the polar molecules is spontaneously given upon adsorption. The strength in the adsorption energies is followed by B-rich_BNNT, SW_BNNT and P_BNNT. Adsorption of non-polar molecules is mainly dictated by dispersion interactions, and, accordingly, the adsorption energies are almost constant for a given molecule irrespective of the type of nanotube.
A first principles study on organic molecule encapsulated boron nitride nanotubes
The Journal of Chemical Physics, 2008
The electronic structures of boron nitride nanotubes (BNNTs) doped by organic molecules are investigated with density functional theory. Electrophilic molecule introduces acceptor states in the wide gap of BNNT close to the valence band edge, which makes the doped system a p-type semiconductor. However, with typical nucleophilic organic molecules encapsulation, only deep occupied molecular states but no shallow donor states are observed. There is a significant electron transfer from BNNT to electrophilic molecule, while the charge transfer between nucleophilic molecule and BNNT is neglectable. When both electrophilic and nucleophilic molecules are encapsulated in the same BNNT, large charge transfer between the two kinds of molecules occurs. The resulted small energy gap can strongly modify the transport and optical properties of the system.
Physical chemistry chemical physics : PCCP, 2015
The pristine BNNTs contain both Lewis acid (boron) and Lewis base (nitrogen) centers at their surface. Interactions of ammonia and borane molecules, representatives of Lewis base and acid as adsorbates respectively, with matching sites at the surface of BNNTs, have been explored in the present DFT study. Adsorption energies suggest stronger chemisorption (about 15-20 kcal mol(-1)) of borane than ammonia (about 5-10 kcal mol(-1)) in both armchair (4,4) and zigzag (8,0) variants of the tube. NH3 favors (8,0) over the (4,4) tube, whereas BH3 exhibits the opposite preference, indicating some chirality dependence on acid-base interactions. A new feature of bonding is found in BH3/AlH3-BNNTs (at the edge site) complexes, where one hydrogen of the guest molecule is involved in three-center two-electron bonding, in addition to dative covalent bond (N: → B). This interaction causes a reversal of electron flow from borane/alane to BNNT, making the tube an electron acceptor, suggesting tailori...
Retracted: Computational study of hydrogen adsorption on potassium-decorated boron nitride nanotubes
International Nano Letters
We have investigated the potassium-decorated boron nitride nanotubes for hydrogen storage using semi-empirical AM1 method. The ultra narrow (3,3) and (5,0) boron nitride nanotubes of same diameter but of different chirality have been used. Both of them show hydrogen storage greater than 8 % by weight. Density of states have been calculated, and it is found that the presence of alpha density of state of potassium results in smaller energy gap; as a result of which, the conductivity of the potassium-decorated boron nitride nanotubes is enhanced as compared to pristine boron nitride nanotubes. Charge decomposition analysis showed that there is significant transfer of charge from adsorbate potassium to boron nitride nanotubes; the same is also confirmed by Mulliken population analysis. For same diameter, due to different electronic configuration, zigzag tube is found to be slightly more favorable for hydrogen adsorption. The results of the present simulation study suggest that the potassiumdecorated boron nitride nanotubes are good candidate for hydrogen adsorption.
Vacuum, 2018
The adsorption of ammonia molecules (NH 3) on the surfaces of (4,4) boron nitride nanotubes (BNNTs), in presence and absence of applied static electric field (SEF, 0.03-z and 0.04-z) and ionic field (IF) of Be +2 , Mg +2 , Ca +2 , Sr +2 and Ba +2 has been investigated using density functional theory (DFT). The changes in geometric and electronic structures of all adsorption configurations were analyzed to characterize the sensitivity of BNNTs towards NH 3 molecules. Our calculations clearly showed that SEF and IF significantly impact the adsorption characteristics of NH 3 molecules on (4,4) BNNTs, indicating the chemisorption process. According to the results, the application of SEF and IF decreased the primary symmetry of BNNTs and consequently enhanced the chemical activity of BNNTs towards NH 3 molecules. Therefore, applying SEF and IF may be a suitable strategy for enhancing gas molecule adsorption capability of BNNTs, improving their sensor applicability.
2021
Based on density functional theory (DFT) and the semiempirical method PM7, we analyze the encapsulation process of polluting gases and/or their adsorption on different sites, viz., on the inner wall, the outer wall, and on the boron nitride (BN) nanotube ends, with chirality (7,7) armchair. DFT calculations are performed using the Perdew–Burke–Ernzerhof (PBE) functional and the M06-2X method through the 6-31G(d) divided valence orbitals as an atomic basis. Various geometrical configurations were optimized by minimizing the total energy for all analyzed systems, including the calculation of vibrational frequencies, which were assumed to be of a nonmagnetic nature, and where the total charge was kept neutral. Results are interpreted in terms of adsorption energy and electronic force, as well as on the analysis of quantum molecular descriptors for all systems considered. The study of six molecules, namely, CCl4, CS2, CO2, CH4, C4H10, and C6H12, in gas phase is addressed. Our results sh...
Monatshefte für Chemie - Chemical Monthly, 2011
Density functional theory (DFT) calculations at the B3LYP/6-31G* level were performed to investigate the adsorbtion properties and quantum molecular descriptors of OCNadsorbed on the external surface of H-capped (6,0), (7,0), and (8,0) zigzag single-walled boron nitride nanotubes. We present the nature of the OCNinteraction in selected sites of the nanotubes. The chemical reactivity of these compounds was compared using DFT-based descriptors such as global softness, global electrophilicity, electronic chemical potential, global hardness, and electronegativity. Our results show that the pristine boron nitride nanotubes can be used as an OCNstorage medium as long as OCNis adsorbed on the exterior walls of the nanotubes because of the high binding energy. Binding energy corresponding to adsorption of OCNon the B site in the (6,0) single-walled boron nitride nanotube was calculated to be-312.3 kJ mol-1. The calculated binding energies for OCNin N-down orientation are higher than those in O-down orientation for all of the configurations. More efficient binding could not be achieved by increasing the nanotube diameter. Adsorption of OCNon the (6,0) zigzag boron nitride nanotube model increases the reactivity of the model.
Adsorption of carbon dioxide and ammonia in transition metal–doped boron nitride nanotubes
Journal of Molecular Modeling, 2019
Density functional theory calculations were carried out to analyze the performance of single-walled boron nitride nanotubes (BNNT) doped with Ni, Pd, and Pt as a sensor of CO 2 and NH 3. Binding energies, equilibrium distances, charge transference, and molecular orbitals, as well as the density of states, are used to study the adsorption mechanism of the gas species on the surface of the nanotube. Our results suggest a considerable rise in the adsorption potential of BNNTs when the doping scheme is employed, as compared with adsorption in pristine nanotubes. Ni-doped nanotubes are observed to be the best candidates for adsorption of both carbon dioxide and ammonia.