Surface Refaceting Mechanism on Cubic Ceria
Surface Refaceting Mechanism on Cubic Ceria
复制标题
立方氧化铈的表面修饰机制
DOI：
10.1021/acs.jpclett.0c02409
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发表时间：
2020
影响因子：
5.7
通讯作者：
Wang Yuemin
中科院分区：
文献类型：
--
作者：
Yang Chengwu;Capdevila-Cortada Marcal;Dong Chunyan;Zhou Yan;Wang Junjun;Yu Xiaojuan;Nefedov Alexei;Heissler Stefan;Lopez Nuria;Shen Wenjie;Woell Christof;Wang Yuemin
固体氧化物的极性表面本质上是不稳定的，并且由于分散的静电能而倾向于重构，因此通常表现出独特的物理和化学性质。然而，这些极性表面的重组机制的定量描述仍然具有挑战性。在这里，我们提供了一个原子级的画面的修饰过程中，管理立方氧化铈纳米粒子的表面极性补偿的基础上获得的准确的参考数据，从定义明确的模型系统。先进的红外光谱，原子分辨透射电子显微镜和密度泛函理论计算的综合结果确定了一个两步的方案，其中初始O-终止（2 × 2）重建，然后通过在高温下的大规模质量输运产生{111}主导的纳米锥的严重refaceting。这种显著的表面重组促进了氧化铈纳米立方体的氧化还原性质，这是增强的CO氧化催化活性的原因。
Polar surfaces of solid oxides are intrinsically unstable and tend to reconstruct due to the diverging electrostatic energy and thus often exhibit unique physical and chemical properties. However, a quantitative description of the restructuring mechanism of these polar surfaces remains challenging. Here we provide an atomic-level picture of the refaceting process that governs the surface polarity compensation of cubic ceria nanoparticles based on the accurate reference data acquired from the well-defined model systems. The combined results from advanced infrared spectroscopy, atomic-resolved transmission electron microscopy, and density functional theory calculations identify a two-step scenario where an initial O-terminated (2 × 2) reconstruction is followed by a severe refaceting via massive mass transport at elevated temperatures to yield {111}-dominated nanopyramids. This significant surface restructuring promotes the redox properties of ceria nanocubes, which account for the enhanced catalytic activity for CO oxidation.