Comparative structural–vibrational study of nano‐urchin and nanorods of vanadium oxide

Abstract

We present a comparative structural-vibrational study of nanostructured systems of V 2 O 5 : nano-urchin (VONURs) which are spherical structures composed of a radially oriented arrays of VOx nanotubes (VOx-NTs) with a volumetric density of ~40 sr -1 , and vanadium oxide nanorods (VOx-NRDs) with an average length of ~100 nm. The Raman scattering of the nano-urchin exhibits a band at 1014 cm -1 related to the distorted gamma conformation of the vanadium pentoxide (γ-V 5+ ). The infrared vibrational spectra of the nanorods sample also exhibit a distorted laminar V 2 O 5 structure with evidence observed for quadravalent V 4+ species at 921 cm -1 .

Atomic Layer Structure of Vanadium Oxide Nanotubes Grown on Nanourchin Structures

“…The NTs are most often composed of an even number of parallel vanadate atomic layers in its distorted octaherdral γ−V 5+ conformation [14,15]. The longest NTs are measured to be several micrometers in length with overall diameters of 80−100 nm and hollow centers typically measured to be 20−30 nm [12,13,16].…”

Low‐Dimensional, Hinged Bar‐code Metal Oxide Layers and Free‐Standing, Ordered Organic Nanostructures from Turbostratic Vanadium Oxide

“…We have estimated interatomic distances in this wavenumber range corresponding to the presence of the distorted pentavalent orthorhombic γ-V 2 O 5 conformation yielding an associated V=O bond length of 0.155 nm. [11] This observation implies that a distortion of the monoclinic vanadate lamina by deformation of the vanadium-oxygen polyhedra, to that of orthorhombic vanadate occurs during HT and influenced by the presence of the thiol molecular template. The nanotube walls are composed of vanadium oxo-anions with either a neutral or negative charge.…”

“…Nanostructures with lamellar structure, [8] scrolled nanotubes, [11,12] nanowires, [13] nanorods [14] and nanourchin [15,16] have been realized using a variety of organic templates during synthesis. Each of these structures relies on the structural direction provided by intercalated or adsorbed organic molecules.…”

Reduced Surfactant Uptake in Three Dimensional Assemblies of VOx Nanotubes Improves Reversible Li+ Intercalation and Charge Capacity

“…Many of these vanadate based nanostructures may be obtained in quantities of the order of grams [18,19] . Together with the electrical and optical properties of vanadium oxide derivatives, this has encouraged its study as a potential new functional material.…”