Oscillations of Cerium Oxidation State Driven by Oxygen Diffusion in Colloidal Nanoceria (CeO2 - x ).

ABSTRACT: The redox performance of CeO2 - x nanocrystals (nanoceria) is always accompanied by the switching of cerium oxidation state between Ce3+ and Ce4+. We monitored Ce3+ → Ce4+ oxidation of nanoceria stimulated by oxidant in aqueous colloidal solutions controlling the luminescence of Ce3+ ions located at different distances from nanoceria surface. The observed Ce3+ luminescence changes indicate that Ce3+ → Ce4+ reaction develops inside nanoceria being triggered by the diffusing oxygen originated from the water splitting on oxidized nanoceria surface. We present the first observation of the pronounced oscillations of Ce3+ luminescence intensity arising from Ce3+ ↔ Ce4+ reversible switching. This threshold effect is to be driven by uptaking and releasing oxygen by nanoceria, when the concentratio

SUBMITTER: Malyukin Y 

PROVIDER: S-EPMC5640564 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature