Theoretical Studies of the Interaction of an Open-Ended Boron Nitride Nanotube (BNNT) with Gas Molecules
ABSTRACT We have systematically studied the effects of several gaseous adsorbates (H2, N2, O2, and H2O) on the electronic properties of open edges of boron nitride nanotubes (BNNTs) by using density functional theory calculations. The results indicate that all of the molecules, except N2, dissociate and chemisorb on open BNNT edges with large adsorption energies because the tube edge has either an open or capped structure and thus has dangling bonds or pentagonal defects. The high reactivity of an open-ended BNNT even can be comparable with that of its carbon counterpart, although the wall of the BNNT is chemically more stable than a single-walled carbon nanotube’s wall. Moreover, we note that adsorption of gases at the tips of open BNNTs can modify their electronic properties in various ways. A considerable amount of charge transferred for the adsorption of gases on the open BNNTs may account for the changes of the electronic properties. Interestingly, the open (5,5) BNNT exhibits the properties of wide-band-gap materials when gases are adsorbed at top sites, while a smaller band gap is observed when these gases are adsorbed on seat sites. Additionally, the magnetic moments of gas-adsorbed N atoms in the open N-rich-ended (8,0) are significantly decreased because the dangling bonds are “saturated”. The present results might be helpful in the design of BNNT-based nanomaterials such as field emitters or nanojunctions.
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ABSTRACT: We have performed a comparative study of nine predominant gas molecules (H2, H2O, O2, CO, CO2, NO, NO2, NH3, and CH3OH) adsorption property on the top surface of the (10, 0) zigzag single-walled pristine Carbon nanotube (C-CNT), Boron doped carbon nanotube (B-CNT), and Silicon doped carbon nanotube (Si-CNT) are investigated by using density functional theory (DFT) computations to exploit their potential applications as gas sensors. For the first time, we calculated the optimal equilibrium position, absorption energy (Ead ), Band structure and density of states (DOS) of the considered gas molecules adsorbed on the open end of zigzag single-walled (10, 0) B-CNT and Si-CNT. Our first principle calculations demonstrate that the B-CNT and Si-CNT adsorbent materials are able to adsorb the considered gas molecules with variety of adsorption energy and their electronic structure dramatic changes in the density of states near the Fermi level. The obtained comparative DFT studies results are useful for designing a high-fidelity gas sensor materials and selective adsorbents for a selective gas sensor.Journal of Nanomaterials 12/2013; 2013. · 1.61 Impact Factor
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ABSTRACT: We have performed studies of the structural and electronic properties of functionalized single wall silicon carbide nanotubes (SW-SiCNTs) with chirality (5,5). Our first principles studies are done using density functional theory. The exchange-correlation energies are modeled according to the Hamprecht-Cohen-Tozer-Handy functional in the generalized gradient approximation (HCTH-GGA) and the DNP basis function with double polarization is applied. To determine the most stable geometry, we have applied the minimum energy criterion considering several initial configurations of the hydroxyl (OH) functional group interacting with the single wall SiCNT. In particular, we tested different orientations of the OH adsorbed on the nanotube surface (oriented towards the Si or C atoms) and at the end of the nanotube. Results indicate that the most favorable geometry corresponds to OH adsorption (chemisorption) at the end of the nanotube. The polarity increases yielding better conditions for solubility and dispersion. The work function of the SW-SiCNT-OH is reduced, which in turn favors conditions for field emission properties (FEPs). Finally, the presence of silicon or carbon mono-vacancies in the functionalized nanotubes suggests this may be a good structure to fabricate semiconductor devicesCentral European Journal of Chemistry 01/2014; 12(1). · 1.33 Impact Factor
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ABSTRACT: The interaction of collagen amino acids with (5, 5) armchair and (9, 0) zigzag single-walled boron nitride nanotubes (BNNTs) are studied using density functional theory. Our results show that the BNNTs can act as a suitable drug delivery vehicle of collagen amino acids within biological systems. DFT-LDA/DNP calculations revealed that the binding and solvation energies were negative for (5, 5)/(9, 0) BNNTs–collagen amino acid complexes implying the thermodynamic favorability and spontaneous interactions of collagen amino acids with BNNTs sidewall. These results were extremely relevant in order to identify the potential applications of functionalized BNNTs as drug delivery systems.Structural Chemistry 01/2014; · 1.90 Impact Factor