In situ XRD and Raman study of the phase transition in V2O5 xerogels

Vanadium oxide xerogel samples (V2O5 center dot nH2O) were successfully synthesized using a liquid phase reaction between alpha-V2O5 and H2O2, as well as through the interaction of amorphous V2O5 films with atmospheric water. The samples were systematically investigated by X-ray diffraction and Raman spectroscopy. Temperature-dependent studies confirmed the existence of two distinct phases. Depending on synthesis and processing protocols, either phase can be stabilized in ambient conditions. It was proved that the formation of a high-temperature phase from amorphous vanadium oxide previously led to some misinterpretations associated with the high-pressure 6-V2O5 polymorph. While current structural models of vanadium oxide xerogel provide some insights, our findings underscore the exciting potential for refining and expanding these models in future research endeavors.