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).