Electron- and Hole-Mediated Reactions in UV-Irradiated O2 Adsorbed on Reduced Rutile TiO2(110)
Electron- and Hole-Mediated Reactions in UV-Irradiated O2 Adsorbed on Reduced Rutile TiO2(110)
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DOI：
10.1021/jp108909p
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发表时间：
2011-01
影响因子：
3.7
通讯作者：
N. G. Petrik;G. Kimmel
中科院分区：
文献类型：
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作者：
N. G. Petrik;G. Kimmel
研究了低温(<；100K)条件下，氧在还原的二氧化钛(110)表面吸附时的紫外光激发反应。当单个O2被化学吸附在每个桥氧空位上时，在长时间的紫外光照射下，只有14%的O2被∼解吸。对于辐照后表面剩余的O2，约有一半解离，另一半处于非解离状态，对空穴介导的光解吸不起作用。对于化学吸附氧的最大覆盖率，光解吸氧的比例大幅增加，但仍仅为∼的40%。然而，当物理吸附氧也存在时，∼最初化学吸附的O2的70%被光解吸。在实验结果的基础上，我们提出了空穴和电子与O2化学吸附在TiO2(110)表面的反应是重要的。空穴介导的反应导致O2光解吸，而电子介导的反应导致O2解离。电子介导的反应解释了总光解吸产率较低的原因。
The ultraviolet (UV) photon-stimulated reactions in oxygen adsorbed on reduced TiO2(110) at low temperatures (<100 K) are studied. When a single O2 is chemisorbed in each bridging oxygen vacancy, only ∼14% of the O2 desorbs after prolonged UV irradiation. For the remaining O2 on the surface after irradiation, about one-half dissociates, and the other one-half is left in a nondissociated state that is inactive for hole-mediated photodesorption. For the maximum coverage of chemisorbed oxygen, the fraction of O2 that photodesorbs increases substantially, but is still only ∼40%. However, when physisorbed oxygen is also present, ∼70% of the initially chemisorbed O2 photodesorbs. On the basis of the experimental results, we propose that both hole- and electron-mediated reactions with O2 chemisorbed on TiO2(110) are important. Hole-mediated reactions lead to O2 photodesorption, while electron-mediated reactions lead to O2 dissociation. The electron-mediated reactions explain the low total photodesorption yield w...