| Abstract
| - Octahedral clusters (CeO2-x)n (n ≤ 85) have been studied using a density functional method (DFT+U) adaptedto model nanocrystalline ceria. The binding energies of the clusters Ce19O32, Ce44O80, and Ce85O160 are shownto converge to the bulk limit almost linearly with respect to the average coordination number of Ce. Theexperimentally detected anomalous lattice expansion for nanoscale (CeO2-x)n particles of decreasing size isexplicitly assigned to the presence of oxygen vacancies. Partially reduced Ce3+ cations are found to occupymore open edge and corner sites of the nanoparticles, whereas most oxidized Ce4+ centers are located inhighly coordinated positions. This finding is crucial for the understanding of ceria reactivity at the nanoscale.
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