IL-assisted synthesis of V₂O₅ nanocomposites and VO₂ nanosheets

Lamellar structures of alternating sheets of crystalline V ₂O₅ (shcherbinaite) and cations from certain imidazolium-based ionic liquids (IL) (e.g. 1-ethyl-3-methyl-imidazolium tetrafluoroborate) were obtained starting from VOCl₃. Surprisingly, growth along the [100] direction of shcherbinaite is suppressed due to the intercalation of the IL cations, which can be attributed to the higher charge density perpendicular to this plane compared to other crystallographic planes. In the lamellar nanostructure, V₂O₅ consists of sheets with just one single unit cell in the [100] direction (i.e. perpendicular to the sheets). Owing to the strong interaction with the imidazolium rings, crystallization of vanadium oxide occurs at relatively moderate temperature of ca. 100 °C. Depending on the heat treatment, diverse vanadium oxide nanostructures can be obtained from the lamellar IL-V₂O₅ nanocomposite, namely V₂O₅, V₂O₃ and VO₂. The structure of the materials was characterized by X-ray scattering, scanning (SEM) and transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS).