One-dimensional electron systems for anchoring growth of carbon nanostructures

Hyldgaard, Per; Jacobson, Niclas; Ruberto, Carlo; Razaznejad, Behrooz; Lundqvist, Bengt I.

doi:10.1016/j.commatsci.2004.12.002

Cited by 2 publications

(3 citation statements)

References 22 publications

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“…38 It has been recently suggested that it may have useful applications in carbon nanotubes fabrication because of its affinity to strongly interact and chemisorb graphite sheets. 40 Test calculations have shown that such metallic state would have a dramatic effect on the reducibility of the vanadia aggregates supported on the (001) surface of the slab. Therefore, we terminated the bottom (001 h) surface by water molecules, thus "quenching'' the metallic state and keeping the Al…”

Section: Modelsmentioning

confidence: 99%

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Vanadium Oxides on Aluminum Oxide Supports. 3. Metastable κ-Al₂O₃(001) Compared to α-Al₂O₃(0001)

2007

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Low-coverage vanadia species (monomers, dimers, trimers, and one-dimensional vanadia rows) as well as vanadium oxide films of varying thickness supported on the metastable κ-Al2O3(001) surface are investigated by density functional theory in combination with statistical thermodynamics. At low-vanadium chemical potentials and typical reducing conditions, species with V−O(3)−Al interface bonds are stable. These aggregates are partially reduced with vanadium in the VIII oxidation state. This correlates with defect formation energy values for the initial removal of lattice oxygen in the range of 1.3−2.7 eV. As the length of the polymeric species increases, the reduction energy decreases. We demonstrate that the support structure does affect the structure of the model catalyst and the lattice oxygen bond strength. On the α-Al2O3(0001) surface, the only stable low-coverage VO x species are dimers with V−O(2)−Al interface bonds and a defect formation energy of 2.8 eV. Reduction remains more facile for vanadia films on κ-Al2O3 than on α-Al2O3. The systematic lower values relate to the presence of tetrahedral sites that allow for significant lattice relaxation upon reduction. Using the oxygen defect formation energy as a reactivity descriptor, we discuss possible effects of the support structure and vanadia loading in Mars-van Krevelen-type oxidation reactions. We also analyze the influence of the support structure on the interface vibrational modes.

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Section: Modelsmentioning

confidence: 99%

“…As a consequence, the existence of a one-dimensional (1D) metallic surface state on κ-Al 2 O 3 (001̄) has been predicted . It has been recently suggested that it may have useful applications in carbon nanotubes fabrication because of its affinity to strongly interact and chemisorb graphite sheets …”

Section: Modelsmentioning

confidence: 99%

Vanadium Oxides on Aluminum Oxide Supports. 3. Metastable κ-Al₂O₃(001) Compared to α-Al₂O₃(0001)

2007

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“…PAHS in the melted liquid crystal could possibly anchor on the internal surface of silica template, which is unaffected by carbonization process. As a result, the tailored crystalline structure is obtained [15,16]. Fig.…”

Section: Methodsmentioning

confidence: 99%

A comparative study of anode properties of two ordered mesoporous carbons with tailored crystalline structure for lithium ion batteries

Cao¹,

Hou²,

Zeng³

et al. 2012

Proceedings of the 2nd International Conference on Electronic and Mechanical Engineering and Information Technology (2012)

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Abstract. Ordered mesoporous carbons (C-1 and C-2) with tailored pore size and defined crystal orientation are prepared by liquid crystal template carbonization method using AR-mesophase pitch as carbon precursors and SBA-15 as template. The topography, pore/crystalline structure are extensively characterized via high-resolution transmission electron microscope (HR-TEM), N 2 adsorption/desorption and powder X-ray diffraction (XRD). The electrochemical properties of C-1 and C-2 as anode materials for lithium ion batteries (LIBs) are examined by galvano-statically charge/discharge and electrochemical impedance spectroscopy (EIS). Materials characterization shows that the carbons prepared in this work replicate the ordered mesoporous structure of the SBA-15 and possess tailored crystalline structure with graphene layers perpendicular to the axial of pore walls. The carbons both display preferable anode performance for LIBs. However, C-2 with thicker pore wall exhibits better properties than C-1 with larger pore size. Possible reasons for different properties are the influence of the pore structure and wall thickness of as-prepared mesoporous carbons.

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One-dimensional electron systems for anchoring growth of carbon nanostructures

Cited by 2 publications

References 22 publications

Vanadium Oxides on Aluminum Oxide Supports. 3. Metastable κ-Al₂O₃(001) Compared to α-Al₂O₃(0001)

Vanadium Oxides on Aluminum Oxide Supports. 3. Metastable κ-Al₂O₃(001) Compared to α-Al₂O₃(0001)

A comparative study of anode properties of two ordered mesoporous carbons with tailored crystalline structure for lithium ion batteries

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One-dimensional electron systems for anchoring growth of carbon nanostructures

Cited by 2 publications

References 22 publications

Vanadium Oxides on Aluminum Oxide Supports. 3. Metastable κ-Al2O3(001) Compared to α-Al2O3(0001)

Vanadium Oxides on Aluminum Oxide Supports. 3. Metastable κ-Al2O3(001) Compared to α-Al2O3(0001)

A comparative study of anode properties of two ordered mesoporous carbons with tailored crystalline structure for lithium ion batteries

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Product

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Vanadium Oxides on Aluminum Oxide Supports. 3. Metastable κ-Al₂O₃(001) Compared to α-Al₂O₃(0001)

Vanadium Oxides on Aluminum Oxide Supports. 3. Metastable κ-Al₂O₃(001) Compared to α-Al₂O₃(0001)