Adsorption of a carbon atom on the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ni</mml:mi></mml:mrow><mml:mrow><mml:mn>38</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>magic cluster and three low-index nickel surfaces: A comparative first-principles study

Zhang, Q.-M.; Wells, Jack; Gong, Xia; Zhang, Zhenyu

doi:10.1103/physrevb.69.205413

Cited by 44 publications

(20 citation statements)

References 53 publications

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“…For monoatomic carbon, all diffusion modes can be considered (surface, subsurface and bulk) while in the case of a carbon dimer, only the surface diffusion mode is usually studied. For the C adatom diffusion on the (111) face of a Ni nanocluster, a barrier of ∼ 0 4 eV was obtained [18], in agreement with the measured activation energy of the experimental CNT growth process, suggesting that surface diffusion is the rate-limiting step [4]. Subsurface and bulk diffusion occur via hopping of interstitial carbon atoms between adjacent tetrahedral and octahedral voids which is generally higher than for adatom diffusion.…”

Section: Introductionsupporting

confidence: 68%

Simulations on the mechanism of CNT bundle growth upon smooth and nanostructured Ni as well as θ-Al2O3 catalysts

Zhukovskii

Piskunov²,

Kotomin

et al. 2011

Open Physics

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In the current study, we have performed ab initio DFT calculations on the gradually growing 2D periodic models of capped single-wall carbon nanotubes (SW CNTs) upon their perpendicular junctions with the Ni(111) substrate, in order to understand the peculiarities of the initial stage of their growth on either smooth or nanostructured catalytic particles. Appearance of the adsorbed carbon atoms upon the substrate follows from the dissociation of CVD hydrocarbon molecules, e.g., CH4: (CH4)ads → (CH)ads+3Hads and (CH)ads → Cads+Hads. (Since the effective growth of CNTs upon Ni nanoparticles occur inside the nanopores of amorphous alumina, we have also simulated analogous surface reactions upon the θ-Al2O3(010) slabs). Association of the adsorbed carbon atoms upon the catalyst surface precedes further swelling of the (Cn)ads islands after appearance of pentagonal defects within a honeycomb sheet which are more probable upon the catalyst surface containing either defects or nanoclusters (as in the case of the nanostructured substrate). The gradual growth of the capped CNTs is considerably more effective upon the nanostructured Ni(111) substrate compared to a smooth nickel substrate (cf. values of CNT adhesion energy per boundary C atom for chiralities of either armchair-type, 4.04 vs. 2.51 eV, or zigzag-type, 4.61 vs. 2.14 eV, respectively). The electronic charge transfer from the Ni catalyst towards the CNTs has been calculated for both chiralities (> 1 e per C atom), i.e., quite strong chemical bonds are formed within the CNT/Ni(111) interconnects.

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Section: Introductionsupporting

confidence: 68%

Simulations on the mechanism of CNT bundle growth upon smooth and nanostructured Ni as well as θ-Al2O3 catalysts

Zhukovskii

Piskunov²,

Kotomin

et al. 2011

Open Physics

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“…This is a slightly stronger bond than that determined with the same functional and code for a (111) surface of a Ni 38 cluster, which is -7.2 eV [35]. The total energy, E tot , for 1 C adsorbed on Ni 55 ( Fig.…”

Section: Resultsmentioning

confidence: 97%

DFT and tight binding Monte Carlo calculations related to single-walled carbon nanotube nucleation and growth

Zhu

Börjesson

Bolton

2010

Carbon

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Density functional theory (DFT) calculations of the nucleation of (5, 5) and (10, 0) single-walled carbon nanotubes (SWNTs) on a 55 atom nickel cluster (Ni 55 ) showed that it requires a larger chemical potential to grow a carbon island (which is the precursor to the SWNTs) on the cluster than to extend the island into a SWNT or to have the carbon atoms dispersed on the cluster surface. Hence, in the thermodynamic limit the island will only form once the (surface of the) cluster is saturated with carbon, and the island will spontaneously form a SWNT at the chemical potentials required to create the island. The DFT (zero Kelvin) and tight binding Monte Carlo (1000 K) also show that there is a minimum cluster size required to support SWNT growth, and that this cluster size can be used to control the diameter, but probably not the chirality, of the SWNT at temperatures relevant to carbon nanotube growth. It also imposes a minimum size of clusters that are used in SWNT regrowth.

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“…Infinite surfaces were shown to be good models for facets, even in the case of the smallest metallic nanoparticles [16]. We primarily considered the lowest energy (111) facets [17], which dominate the surfaces of fcc-metal nanoparticles [18].…”

Section: Methodsmentioning

confidence: 99%

“…Adatoms on a (111) surface are threefold coordinated and occupy two different positions, ccp and hcp [16]. These two positions differ only by the arrangement of metal atoms in the subsurface monolayer and their chemical potentials are nearly equal within 0.1 eV (cf.…”

Section: Binding Of Monoatomic and Diatomic Carbonmentioning

confidence: 99%

Carbon diffusion in CVD growth of carbon nanotubes on metal nanoparticles

Yazyev¹,

Pasquarello²

2008

Physica Status Solidi (b)

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Diffusion of carbon is the crucial step in chemical vapor deposition (CVD) growth of carbon nanotubes (CNTs) on metal nanoparticles. Using first principles techniques we model the binding and diffusion of carbon atoms and dimers on late transition (Ni, Pd, Pt) and coinage (Cu, Ag, Au) metal catalysts. We consider various diffusion mechanisms including both surface and subsurface channels, finding the lowest activation barriers for carbon adatoms on nanoparticles of coinage metals. For these metals, our calculations further show that the diffusion is restricted to the nanoparticle surface when diatomic carbon is initially obtained from the decomposition of the precursor gas. In combination with the results for the binding of CNT fragments to metal nanoparticles, we conclude that coinage metal catalysts, in particular Cu, favor CVD growth of CNTs at low temperatures and with narrow chirality distributions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Adsorption of a carbon atom on theNi38magic cluster and three low-index nickel surfaces: A comparative first-principles study

Cited by 44 publications

References 53 publications

Simulations on the mechanism of CNT bundle growth upon smooth and nanostructured Ni as well as θ-Al2O3 catalysts

Simulations on the mechanism of CNT bundle growth upon smooth and nanostructured Ni as well as θ-Al2O3 catalysts

DFT and tight binding Monte Carlo calculations related to single-walled carbon nanotube nucleation and growth

Carbon diffusion in CVD growth of carbon nanotubes on metal nanoparticles

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