Reaction of O2 with Subsurface Oxygen Vacancies on TiO2 Anatase (101)
Reaction of O2 with Subsurface Oxygen Vacancies on TiO2 Anatase (101)
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DOI：
10.1126/science.1239879
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发表时间：
2013-08-30
期刊：
影响因子：
56.9
通讯作者：
Diebold, Ulrike
中科院分区：
文献类型：
--
作者：
Setvin, Martin;Aschauer, Ulrich;Diebold, Ulrike
吸附在金属氧化物上的氧（O-2）在催化氧化反应、化学传感和电化学分析中是重要的。例如，强吸附需要从氧空位（V（O）s）或掺杂剂转移负电荷。利用扫描隧道显微镜，我们观察、转化并结合理论确定了掺杂铌的锐钛型（二氧化钛，TiO 2）（101）表面上O-2分子的性质。V（O）只存在于本体中，但我们用带强烈负电荷的扫描隧道显微镜尖端将它们拉到表面。O-2以超氧（O-2（-））形式吸附在五配位的Ti位上，转化为过氧（O-2（2-）），并通过与V-O反应，以（O-2）（O）形式进入阴离子表面晶格位。当O-2直接与V（O）s在表面或表面以下反应时，也形成这种所谓的桥接二聚体。
Oxygen (O-2) adsorbed on metal oxides is important in catalytic oxidation reactions, chemical sensing, and photocatalysis. Strong adsorption requires transfer of negative charge from oxygen vacancies (V(O)s) or dopants, for example. With scanning tunneling microscopy, we observed, transformed, and, in conjunction with theory, identified the nature of O-2 molecules on the (101) surface of anatase (titanium oxide, TiO2) doped with niobium. V(O)s reside exclusively in the bulk, but we pull them to the surface with a strongly negatively charged scanning tunneling microscope tip. O-2 adsorbed as superoxo (O-2(-)) at fivefold-coordinated Ti sites was transformed to peroxo (O-2(2-)) and, via reaction with a V-O, placed into an anion surface lattice site as an (O-2)(O) species. This so-called bridging dimer also formed when O-2 directly reacted with V(O)s at or below the surface.