Direct Observation of Site-Specific Molecular Chemisorption of O2 on TiO2(110)
Direct Observation of Site-Specific Molecular Chemisorption of O2 on TiO2(110)
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DOI：
10.1021/jz101535f
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发表时间：
2010-12
影响因子：
5.7
通讯作者：
Zhi-tao Wang;Yingge Du;Z. Dohnálek;I. Lyubinetsky
中科院分区：
文献类型：
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作者：
Zhi-tao Wang;Yingge Du;Z. Dohnálek;I. Lyubinetsky
分子化学吸附的O2物种直接成像还原TiO2（110）在50 K的高分辨率扫描隧道显微镜（STM）。两个不同的O2吸附通道，一个在桥接氧空位（VO）和另一个在5倍协调终端钛原子（Ti5c），已被确定。虽然O2物种在Ti5c网站出现作为一个单一的突出中心的Ti5c行，在VO的O2表现出自己的VO功能消失。据发现，STM针尖可以很容易地解离O2物种，除非使用非常低的幅度的隧穿参数。在这两个不同的网站在低温下化学吸附的O2分子是最有可能的前体的两个O2解离通道，观察到在温度高于150和230 K的VO和Ti5C网站，分别。
Molecularly chemisorbed O2 species were directly imaged on reduced TiO2(110) at 50 K with high-resolution scanning tunneling microscopy (STM). Two different O2 adsorption channels, one at bridging oxygen vacancies (VO) and another at 5-fold coordinated terminal titanium atoms (Ti5c), have been identified. While O2 species at the Ti5c site appears as a single protrusion centered on the Ti5c row, the O2 at VO manifests itself by a disappearance of the VO feature. It is found that the STM tip can easily dissociate O2 species, unless extremely low magnitude of the tunneling parameters are used. The O2 molecules chemisorbed at low temperatures at these two distinct sites are the most likely precursors for the two O2 dissociation channels, observed at temperatures above 150 and 230 K at the VO and Ti5c sites, respectively.