Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
Nat Commun. 2013;4:2214. doi: 10.1038/ncomms3214.
The chemical reactivity of different surfaces of titanium dioxide (TiO2) has been the subject of extensive studies in recent decades. The anatase TiO2(001) and its (1 × 4) reconstructed surfaces were theoretically considered to be the most reactive and have been heavily pursued by synthetic chemists. However, the lack of direct experimental verification or determination of the active sites on these surfaces has caused controversy and debate. Here we report a systematic study on an anatase TiO2(001)-(1 × 4) surface by means of microscopic and spectroscopic techniques in combination with first-principles calculations. Two types of intrinsic point defects are identified, among which only the Ti(3+) defect site on the reduced surface demonstrates considerable chemical activity. The perfect surface itself can be fully oxidized, but shows no obvious activity. Our findings suggest that the reactivity of the anatase TiO2(001) surface should depend on its reduction status, similar to that of rutile TiO2 surfaces.
近年来，二氧化钛（TiO2）不同表面的化学反应性一直是广泛研究的主题。锐钛矿 TiO2(001)及其（1×4）重构表面在理论上被认为是最具反应性的，并受到合成化学家的广泛关注。然而，这些表面上活性位的直接实验验证或确定的缺乏导致了争议和争论。在这里，我们通过微观和光谱技术结合第一性原理计算，对锐钛矿 TiO2(001)-(1×4)表面进行了系统的研究。确定了两种类型的本征点缺陷，其中只有还原表面上的 Ti(3+)缺陷位表现出相当大的化学活性。完整的表面本身可以完全被氧化，但没有明显的活性。我们的发现表明，锐钛矿 TiO2(001)表面的反应性应该取决于其还原状态，类似于金红石 TiO2 表面。
