O-vacancy and surface on CeO₂: A first-principles study

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• 作者：Siqi Shi ; Yuanhao Tang ; Chuying Ouyang ; Lixia Cui ; Xiaogui Xin ; Peijuan Li ; Weiwei Zhou ; Hua Zhang ; Minsheng Lei ; Liquan Chen
• 关键词：A. Ceramics ; A. Oxides ; A. Surfaces ; D. Electronic structure ; C. Ab initio calculations
• 刊名：Journal of Physics and Chemistry of Solids
• 出版年：2010
• 出版时间：May 2010
• 年：2010
• 卷：71
• 期：5
• 页码：788-796
• 全文大小：1338 K

文摘

Atomic and electronic structures of CeO₂ (1 1 1), (1 1 0) and (1 0 0) surfaces are investigated using the first-principles density functional theory taking into account the on-site Coulomb interaction. Both the stoichiometric and O-deficient surfaces are examined in order to clarify the overall features. The CeO₂ (1 1 1) is found to be the most stable surface, followed by the (1 1 0) and (1 0 0) surfaces, consistent with experimental observations. Three surfaces exhibit different features of relaxation. Large relaxations are found at the (1 1 0) and (1 0 0) surfaces, while very small changes are observed at the (1 1 1) surface. It is found that the O-vacancy occurs more readily at the (1 1 0) surface as compared with the (1 1 1) surface. Furthermore, the formation energies of the O-vacancy in the surfaces are lower than that in the bulk. The energetically favorable O-vacancy locates in the second O-atomic layer for the (1 1 1) while at the surface layer for the (1 1 0). The excess electrons left with the removal of the O atom are distributed in the first two layers with certain (a considerable) fraction filling the Ce-4f states.