How the Environment Encourages the Natural Formation of Hydrated VO.

Herein, we report the microscopic and spectroscopic signatures of the hydrated VO phase, prepared from the α-VO powder, which was kept in deionized water inside an airtight glass container for approximately 2.5 years. The experimental results show an evolution of the V component in V 2p core energy level spectra, and a peak corresponding to σ-OH bond appeared in the valence band spectra in the hydrated VO powder sample due to the water intercalation. Vanadium metal oxide particles were found to be self-nucleated into micro/nanorods after a long period of exposure to an extremely humid environment. The distinct features in the spectra obtained with high-resolution transmission electron microscopy, micro-Raman scattering, and X-ray photoelectron spectroscopy confirmed the presence of structural water molecules for the first time in the long-aged naturally hydrated VO phase.