Activation of Cu(111) surface by decomposition into nanoclusters driven by CO adsorption
Activation of Cu(111) surface by decomposition into nanoclusters driven by CO adsorption
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DOI：
10.1126/science.aad8868
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发表时间：
2016-01-29
期刊：
影响因子：
56.9
通讯作者：
Salmeron, Miquel
中科院分区：
文献类型：
--
作者：
Eren, Baran;Zherebetskyy, Danylo;Salmeron, Miquel
铜（Cu）的（111）面是其最致密和能量最低的表面，当暴露于一氧化碳（CO）气体时变得不稳定。扫描隧道显微镜显示，在室温下，在0.1至100托的压力范围内，表面分解成簇装饰的CO分子连接到边缘原子。在0.2和几托CO之间，簇在分钟的尺度上变得移动的。密度泛函理论表明，CO与低配位Cu原子结合的能量增益和Cu与相邻原子结合的减弱有助于推动这一过程。特别是对于较软的金属，这两种效应的最佳平衡发生在反应条件附近。团簇的形成激活了表面的水解离，这是水煤气变换反应中的重要步骤。
The (111) surface of copper (Cu), its most compact and lowest energy surface, became unstable when exposed to carbon monoxide (CO) gas. Scanning tunneling microscopy revealed that at room temperature in the pressure range 0.1 to 100 Torr, the surface decomposed into clusters decorated by CO molecules attached to edge atoms. Between 0.2 and a few Torr CO, the clusters became mobile in the scale of minutes. Density functional theory showed that the energy gain from CO binding to low-coordinated Cu atoms and the weakening of binding of Cu to neighboring atoms help drive this process. Particularly for softer metals, the optimal balance of these two effects occurs near reaction conditions. Cluster formation activated the surface for water dissociation, an important step in the water-gas shift reaction.