The photoluminescence properties and reversible photoinduced spectral change of CeO2 bulk, film and nanocrystals

The photoluminescence properties of different pristine CeO2 specimens (bulk crystal, film, and nanocrystals) have been studied at different temperatures between 7 K and room temperature. The photoinduced luminescence spectral change has been observed at room temperature for the first time. The phenomenon observed in a vacuum is explained as a photoinduced associative detachment Of O-2 on the specimen surface, while that observed in O-2 gas is explained as a photoinduced dissociative adsorption Of O-2 on the specimen surface. The photoreduction is accompanied both by a valence number change of cerium ions (Ce4+ --> Ce3+) and by oxygen-defect formation. Such reversible photoinduced phenomena of CeO2 can be applied to light control of the oxygen-storage and oxygen-release processes at metal-oxide surfaces. A tentative result obtained at room temperature for an oxygen-storage material (0.3)CeO2-(0.7)ZrO2 solid solution is also described. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim