Anodic Deposition of Vanadium Oxides for Thermal-Induced Growth of Vanadium Oxide Nanowires

Abstract

Hydrous vanadium oxides (denoted hereafter as ) were prepared by anodic deposition from an aqueous solution containing and . X-ray photoelectron spectroscopic analyses demonstrated that the valence of vanadium in the deposits was mixed pentavalent and tetravalent. Growth of vanadium oxide nanowires to unique sea-urchin-like structure from the as-deposited oxides can be induced by postdeposition annealing in air at with time . The success in growing one-dimensional (1D) vanadium oxide nanowires strongly depends on the deposition variables such as the ratio (adjusted by addition) in the solution and the applied current density during anodic deposition. From the transmission electron microscopic and selected area electron diffraction analyses, nanowires show single-crystalline structures of , , and . This thermal-induced growth of 1D vanadium oxide nanowires is attributable to the extrusion of , , and single crystals originating from the thermal expansion of .