IL-assisted synthesis of V2O5 nanocomposites and VO2 nanosheets

Lamellar structures of alternating sheets of crystalline V2O5 (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 degrees 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).