To observe oxygen vacancy influence over pure CeO 2 Raman spectrum profile, nanorods were synthesized and submitted to an in situ strategy to generate or suppress reversibly the oxygen vacancies. No changes were observed in CeO 2 nanorod Raman spectra. However, after the comminution of these nanorods, a reversible frequency downshift in CeO 2 T 2g Raman band was observed. The catalytic activities of CO oxidation were compared for both pristine and comminuted samples. The results indicate that the comminuted sample show higher catalytic activity than the pristine one. This enhancement on catalytic activity is attributed to the exposure of the CeO 2 {110} crystals facets after the comminution process.

This work reports on the in situ strategy to reversibly generate or suppress oxygen vacancies on α-MoO3 which were probed by Raman spectroscopy.

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