Raman spectroscopy-in situ characterization of reversibly intercalated oxygen vacancies in α-MoO(3)

This work reports on the in situ strategy to reversibly generate or suppress oxygen vacancies on α-MoO(3) which were probed by Raman spectroscopy. Reversible changes in two features of the α-MoO(3) Raman spectrum could be correlated to the generation of oxygen vacancies: displacement of the T(b) band frequency and the intensity decrease of the symmetrical stretching (ν(s)) band. These two features could be used to qualitatively describe oxygen vacancies. Raman results also indicate that oxygen vacancies are located in the interlayer region of the α-MoO(3) lattice. This observation is corroborated by in situ X-ray diffraction, which also indicates the absence of nonstoichiometric phase transitions.