1,720,975 research outputs found
Mismatch Strain versus Dangling Bonds: Formation of "Coin-Roll Nanowires" by Stacking Nanosheets
No full text(Figure Presented) The third dimension comes to the rescue in the synthesis of laterally confined 2D crystals. Graphene-type sheets of layered metal(IV) chalcogenides are stabilized by stacking to form nano-objects that resemble a coin roll. Mismatch strain between NbS2 and WS2 lattices is important for the stabilization of the coin-roll structure as well as for preventing the formation of the intrinsically more stable scroll structures such as fullerenes or nanotubes. © 2010 Wiley-VCH Verlag GmbH &. Co. KGaA
Mismatch Strain versus Dangling Bonds: Formation of "Coin-Roll Nanowires" by Stacking Nanosheets
No full textStructure analysis of titanate nanorods by automated electron diffraction tomography
No full textA hitherto unknown phase of sodium titanate, NaTi3O6(OH)center dot 2H(2)O, was identified as the intermediate species in the synthesis of TiO2 nanorods. This new phase, prepared as nanorods, was investigated by electron diffraction, X-ray powder diffraction, thermogravimetric analysis and high-resolution transmission electron microscopy. The structure was determined ab initio using electron diffraction data collected by the recently developed automated diffraction tomography technique. NaTi3O6(OH)center dot 2H(2)O crystallizes in the monoclinic space group C2/m. Corrugated layers of corner- and edge-sharing distorted TiO6 octahedra are intercalated with Na+ and water of crystallization. The nanorods are typically affected by pervasive defects, such as mutual layer shifts, that produce diffraction streaks along c*. In addition, edge dislocations were observed in HRTEM images. RI Tremel, Wolfgang/D-8125-2011; Andrusenko, Iryna/E-6239-2011; Mugnaioli, Enrico/E-6237-2011; Kolb, Ute/A-2642-201
Interaction of Alkaline Metal Cations with Oxidic Surfaces: Effect on the Morphology of SnO2 Nanoparticles
No full textReaction pathways to SnO2 nanomaterials through the hydrolysis of hydrated tin tetrachloride precursors were investigated. The products were prepared solvothermally starting from hydrated tin tetrachloride and various (e.g., alkali) hydroxides. The influence of the precursor base on the final morphology of the nanomaterials was studied. X-ray powder diffraction (XRD) data indicated the formation of rutile-type SnO2. Transmission electron microscopy (TEM) studies revealed different morphologies that were formed with different precursor base cations. Data from molecular dynamics (MD) simulations provide theoretical evidence that the adsorption of the cations of the precursor base to the faces of the growing SnO2 nanocrystals is crucial for the morphology of the nanostructures. RI Birkel, Alexander/D-6123-2011; Tremel, Wolfgang/D-8125-2011; Mugnaioli, Enrico/E-6237-2011; Loges, Niklas/F-2479-201
Synthesis of Fullerene- and Nanotube-Like SnS2 Nanoparticles and Sn/S/Carbon Nanocomposites
No full textSnS2 nested fullerene-type (IF) nanoparticles, nanotubes, and SnS2/C hybrid nanostructures were obtained by vapor transport starting from elemental tin and CS2. The reaction was carried out in a single-step process by heating elemental tin metal powder in a horizontal tube furnace at 800-1000 degrees C. TEM analysis allowed proposing a plausible mechanism for the formation of fullerene-like particles of SnS2 as well as tubes and scrolls from nanosheets of SnS2. Pure material could be obtained by optimizing the reaction based on a product analysis using powder X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) combined with energy-dispersive X-ray spectroscopy (EDX). RI Kolb, Ute/A-2642-2011; Tremel, Wolfgang/D-8125-2011; Mugnaioli, Enrico/E-6237-201
Synthesis of Fullerene- and Nanotube-Like SnS2 Nanoparticles and Sn/S/Carbon Nanocomposites
No full textSnS 2 nested fullerene-type (IF) nanoparticles, nanotubes, and SnS 2/C hybrid nanostructures were obtained by vapor transport starting from elemental tin and CS 2. The reaction was carried out in a single-step process by heating elemental tin metal powder in a horizontal tube furnace at 800-1000 ° C. TEM analysis allowed proposing a plausible mechanism for the formation of fullerene-like particles of SnS 2 as well as tubes and scrolls from nanosheets of SnS 2. Pure material could be obtained by optimizing the reaction based on a product analysis using powder X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) combined with energy-dispersive X-ray spectroscopy (EDX). © 2009 American Chemical Society
Asymmetric tungsten oxide nanobrushes via oriented attachment and Ostwald ripening
No full textTungsten oxide nanobrushes were synthesized using a solvothermal approach that lead to self-branching in the presence of citric acid and hexadecylamine as surfactants. Our synthetic approach yielded branched nanorods of tungsten oxide in a single synthetic step. Based on our results, we propose a phenomenological pathway for the formation, branching, and assembly of these tungsten oxide brushes. The formation of tungsten oxide brushes proceeds by thermal decomposition of ammonium tungstate in the presence of citric acid and hexadecylamine. The pale blue powder obtained after solvothermal reaction was analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The field emission (FE) properties of the tungsten oxide nanostructures which can be tailored by their aspect ratio and the hierarchical nanostructures follow a Fowler-Nordheim behavior. RI Tremel, Wolfgang/D-8125-2011; Mugnaioli, Enrico/E-6237-2011; Kolb, Ute/A-2642-2011; GOLBERG, Dmitri/H-2776-201
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