Cu <sub><i>x</i></sub> O / Cu（111）“ 29”结构的结构精确模型：DFT和STM研究,The Journal of Physical Chemistry C

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Cu _x O / Cu（111）“ 29”结构的结构精确模型：DFT和STM研究
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2016-05-10 00:00:00 , DOI: 10.1021/acs.jpcc.6b01284
Andrew J. Therrien ₁ , Renqin Zhang ₂ , Felicia R. Lucci ₁ , Matthew D. Marcinkowski ₁ , Alyssa Hensley ₂ , Jean-Sabin McEwen _{2,

3,

4} , E. Charles H. Sykes ₁

Affiliation

铜是许多重要化学反应的常用催化剂，包括低温水煤气变换，选择性催化还原NO _x，甲醇合成，甲醇蒸汽重整和甲醇部分氧化。在这些反应过程中，表面氧化程度或活性位点的氧化态一直存在争议，并且已知会对反应速率产生很大影响。因此，阐明铜表面氧化物的原子尺度结构是全面理解多相催化反应机理的重要一步。所谓的“ 29”单层氧化膜是Cu（111）氧化过程中的常见中间体。迄今为止，其大尺寸的晶胞阻碍了其结构的确定模型的发展。使用高分辨率扫描隧道显微镜（STM）和密度泛函理论（DFT）计算，我们得出了“ 29” Cu _x的模型在Cu（111）上形成O膜。在一定范围的偏差下，实验和计算STM图像之间有很好的一致性。通过从第一性原理构建相图，我们进一步发现，从DFT计算得出的“ 29”结构在所考虑的实验条件下确实是最稳定的结构。这项工作产生了“ 29”氧化膜的原子尺度结构的准确图片，因此是开始了解该催化相关表面上的吸附位点和反应机理的基础。

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Structurally Accurate Model for the “29”-Structure of CuxO/Cu(111): A DFT and STM Study

Copper is a common catalyst for many important chemical reactions including low-temperature water gas shift, selective catalytic reduction of NO_x, methanol synthesis, methanol steam reforming, and partial oxidation of methanol. The degree of surface oxidation, or the oxidation state of the active site, during these reactions has been debated and is known to have a large influence on the reaction rates. Therefore, elucidating the atomic-scale structure of copper surface oxides is an important step toward a fuller understanding of reaction mechanisms in heterogeneous catalysis. The so-called “29” monolayer oxide film is a common intermediate in the oxidation of Cu(111). The large size of its unit cell has thus far prevented the development of a definitive model for its structure. Using high-resolution scanning tunneling microscopy (STM) and density functional theory (DFT) calculations, we arrive at a model for the “29” Cu_xO film on Cu(111). There is very good agreement between experimental and computational STM images over a range of biases. Through the construction of a phase diagram from first-principles, we further find that the “29” structure derived from the DFT calculations is indeed the most stable structure under the experimental conditions considered. This work yields an accurate picture of the atomic scale structure of the “29” oxide film and therefore a basis for beginning to understand adsorption sites and reaction mechanisms on this catalytically relevant surface.

更新日期：2016-05-10

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