The role of interstitial sites in the Ti3d defect state in the band gap of Titania
The role of interstitial sites in the Ti3d defect state in the band gap of Titania
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DOI：
10.1126/science.1159846
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发表时间：
2008-06-27
期刊：
影响因子：
56.9
通讯作者：
Besenbacher, Flemming
中科院分区：
文献类型：
--
作者：
Wendt, Stefan;Sprunger, Phillip T.;Besenbacher, Flemming
二氧化钛（TiO 2）在催化、光化学和传感方面有许多用途，这些用途与氧化物的还原有关。通常，假定桥接氧（O-br）空位导致金红石TiO 2（110）的带隙中的Ti 3d缺陷态。从高分辨扫描隧道显微镜和光电子能谱测量，我们提出，在近表面区域的Ti晶体可能是主要负责的缺陷态的带隙。我们认为，这些供体特异性位点发挥了关键作用，并可能决定随后的表面化学，如提供所需的O-2吸附和解离的电子电荷。具体来说，我们确定了第二个O-2解离通道，发生在Ti槽内，除了O-2解离通道中的O-br空位。全面的密度泛函理论计算支持这些实验观察。
Titanium dioxide ( TiO2) has a number of uses in catalysis, photochemistry, and sensing that are linked to the reducibility of the oxide. Usually, bridging oxygen ( O-br) vacancies are assumed to cause the Ti3d defect state in the band gap of rutile TiO2( 110). From high- resolution scanning tunneling microscopy and photoelectron spectroscopy measurements, we propose that Ti interstitials in the near- surface region may be largely responsible for the defect state in the band gap. We argue that these donor- specific sites play a key role in and may dictate the ensuing surface chemistry, such as providing the electronic charge required for O-2 adsorption and dissociation. Specifically, we identified a second O-2 dissociation channel that occurs within the Ti troughs in addition to the O-2 dissociation channel in O-br vacancies. Comprehensive density functional theory calculations support these experimental observations.