Functional Materials, 23, No.2 (2016), p.202-205.
Structural rearrangement and change of cerium valence in cerium dioxide (CeO2) nanocrystals
1V.Karazin Kharkiv National University, 4 Svobody Sq., 61077 Kharkiv, Ukraine
2Institute for Scintillation Materials, STC Institute for Single Crystals , National Academy of Sciences of Ukraine, 60 Nauky Ave., 61001 Kharkiv, Ukraine
For CeO2 nanocrystals a large number of cerium ions undergo Ce4+→ Ce3+ transition leading to formation of oxygen-deficient CeO2-x phase in the subsurface layer of nanocrystal. Such structural rearrangement leads to density gradient in ceria nanocrystals changing thereby the elastic constants of material. The analysis of free energy balance has shown that formation of highly deficient CeO2-x phase occurs inevitably for the nanocrystals with sizes d≤6 nm.
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