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.