Funct. Mater. 2018; 25 (3): 439-444.

doi:https://doi.org/10.15407/fm25.03.439

Formation of oxygen vacancies in ceria-zirconia nanocrystals studied by spectroscopic techniques

E.N.Okrushko, V.V.Seminko, P.O.Maksimchuk, I.I.Bespalova, Yu.V.Malyukin

Institute for Scintillation Materials, STC Institute for Single Crystals National Academy of Sciences, 60 Nauky Ave, 61072 Kharkiv, Ukraine

Abstract: 

Incorporation of doped ions with different ionic radius (like Zr4+) or valence state (like Eu3+) into CeO2 structure leads to sufficient modification of the processes of oxygen transport due to formation of additional oxygen vacancies (Ov). These vacancies can form complexes with doped ions (RE-Ov-RE) or cerium ions (Ce3+-Ov-Ce3+) determining the oxygen mobility in these structures. In the paper the formation of oxygen vacancies in ceria (CeO2-x) and ceria-zirconia (CeO2-ZrO2) nanocrystals was studied by conventional spectroscopic techniques. Ratio between intensities of 5D0->7F1 and 5D07F2 spectral lines of Eu3+ ions was used for determination of the content of oxygen vacancies and their location within ceria-zirconia nanocrystal. It was shown that while high-temperature treatment of 50 nm ceria nanocrystal in reducing atmosphere leads only to slight change of the content of oxygen vacancies which are formed preferably near its surface, incorporation of 20 % of zirconium ions is manifested in almost tenfold increase of the content of oxygen vacancies as compared to CeO2-x nanocrystal, and these vacancies are formed within whole nanoparticle.

Keywords: 
ceria-zirconia, nanocrystal, oxygen vacancies, luminescence.
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