Electron localization determines defect formation on ceria substrates
Electron localization determines defect formation on ceria substrates
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DOI：
10.1126/science.1111568
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发表时间：
2005-07-29
期刊：
影响因子：
56.9
通讯作者：
Rosei, R
中科院分区：
文献类型：
--
作者：
Esch, F;Fabris, S;Rosei, R
二氧化铈（CeO（2））作为氧缓冲剂和贵金属催化活性载体的高性能依赖于在由氧空位形成控制的反应位点处晶格氧的有效供应。我们使用高分辨率扫描隧道显微镜和密度泛函计算来解开（111）表面上的表面和亚表面氧空位的局部结构。释放的氧留下的电子定域在铈离子上。超过两个空位的簇专门暴露这些还原的铈离子，主要是通过包括表面下的空位，因此在空位簇形成的过程中发挥至关重要的作用。这些结果对我们理解可还原稀土氧化物的氧化过程具有一定的意义。
The high performance of ceria (CeO(2)) as an oxygen buffer and active support for noble metals in catalysis relies on an efficient supply of lattice oxygen at reaction sites governed by oxygen vacancy formation. We used high-resolution scanning tunneling microscopy and density functional calculations to unravel the local structure of surface and subsurface oxygen vacancies on the (111) surface. Electrons left behind by released oxygen localize on cerium ions. Clusters of more than two vacancies exclusively expose these reduced cerium ions, primarily by including subsurface vacancies, which therefore play a crucial role in the process of vacancy cluster formation. These results have implications for our understanding of oxidation processes on reducible rare-earth oxides.