Morphology and Topochemical Reactions of Novel Vanadium Oxide Nanotubes

Abstract

Vanadium oxide nanotubes were obtained as the main product in a sol−gel reaction followed by hydrothermal treatment from vanadium(V) alkoxide precursors and primary amines (C n H2 n +1NH2 with 4 ≤ n ≤ 22) or α,ω-diamines (H2N[CH2] n NH2 with 14 ≤ n ≤ 20). The structure of the nanotubes has been characterized by transmission electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, and magnetic measurements. The tubes are up to 15 μm long and have outer diameters ranging from 15 to 150 nm and inner diameters from 5 to 50 nm. The tube walls consist of 2−30 crystalline vanadium oxide layers with amine or diamine molecules intercalated in between. The distance between the layers (1.7−3.8 nm) is proportional to the length of the alkylamine, which acts as a structure-directing template. The structure within the layers has a square metric with a ≈ 0.61 nm. Cross-sectional TEM images demonstrate the predominance of serpentine-like scrolls rather than of concentric tubes. The intercalated templates can be easily substituted, e.g. by diamines, while the tubular morphology is preserved. This points to a highly flexible structure.

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

“…We note that unlike other vanadate systems, e.g. amine intercalated V 2 O 5 , [15,53] rolling of the laminar fibers does not occur, but rather site-specific bending and ultimately breakage of the vanadate lamina is observed. The cleaved segments form macroscopic defects in the nanofibers leaving mainly organic moleculecontaining areas segmented periodically by inorganic layers in a barcoded manner.…”

Morphological Evolution of (NH4)0.5V2O5·mH2O Fibers into Belts, Triangles, and Rings

“…For instance, Nesper et al 8 synthesized vanadium oxide nanotubes via the intercalation of primary alkylamines. Luca et al 9,10 prepared mesoporous sieves of vanadium oxide via the intercalation of tetramethylammonium cations.…”

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

“…Although the majority of research and development has been based on carbon nanotubes, considerable attention is now being directed to transition metal nanostructures based on their metal oxides which, due to their versatile chemical properties often modulable by changes in the oxidation state of in the metal coordination sphere, may lead to a variety of products and tunable materials [7,8].…”