How the Environment Encourages the Natural Formation of Hydrated V 2 O 5 .

Herein, we report the microscopic and spectroscopic signatures of the hydrated V 2 O 5 phase, prepared from the α-V 2 O 5 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 4+ component in V 2p 3/2 core energy level spectra, and a peak corresponding to σ-OH - bond appeared in the valence band spectra in the hydrated V 2 O 5 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 V 2 O 5 phase.