Imaging oxygen molecular adsorption and dissociation on the Ti site of rutile TiO₂(110) surface with real configuration at 78 K by atomic force microscopy
Imaging oxygen molecular adsorption and dissociation on the Ti site of rutile TiO₂(110) surface with real configuration at 78 K by atomic force microscopy
复制标题
通过原子力显微镜对 78 K 下真实构型的金红石 TiO−(110) 表面 Ti 位点上的氧分子吸附和解离进行成像
DOI：
10.1039/d0cp03549a
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发表时间：
2020
影响因子：
3.3
通讯作者：
Yan Jun Li
中科院分区：
文献类型：
--
作者：
Huan Fei Wen;Hongqian Sang;Yasuhiro Sugawara;Yan Jun Li
了解氧在金红石型TiO2表面五重配位钛（Ti5c）位点上的吸附和解离作用，对于阐明化学反应过程具有重要意义。在78 K原子分辨率下，通过原子力显微镜直接观察了分子吸附O2的三种不同构型（平行侧对、倾斜侧对和端对）及其解离过程。我们的实验结果表明，电场刺激可以改变三种吸附O2的构型。吸附O2的初始构型和O2构型的转变与其覆盖范围有关。另一方面，隧道电流刺激可以解离这些O2，表明它们是O合原子（Oad）的前体。提出电场刺激的作用有助于这三种吸附O2构型的转变，而隧道电流的作用是导致吸附O2解离的主要因素。此外，根据Oad的原子对比和高度直方图，观察到Oad的不同电荷态，这些电荷态可以在表面区域共存。本研究直观地观察了O2在Ti5c位点上的吸附和解离，因此有望有助于理解氧化物表面的表面反应。
Understanding oxygen adsorption and dissociation on the five-fold coordinated titanium (Ti5c) site of the rutile TiO2 surface is important in clarifying chemical reaction processes. Accordingly, three different configurations of molecularly adsorbed O2, including parallel side-on, inclined side-on and end-on configurations, and their dissociation were directly observed with atomic resolution at 78 K by atomic force microscopy. Our results experimentally demonstrated that the three adsorbed O2 configurations could be changed by electric field stimulation. The initial configurations of the adsorbed O2 and transition of O2 configurations were related to their coverage. On the other hand, the tunneling current stimulation could dissociate these O2 species, indicating that they are precursors for the O adatom (Oad). It is proposed that the effect of electric field stimulation contributes to the transition of these three adsorbed O2 configurations, and the effect of the tunneling current is the main factor for the dissociation of the adsorbed O2. In addition, based on the atomic contrast and height histograms of Oad, different charge states of Oad were observed, which could coexist on the surface region. The present study demonstrates an intuitional observation of O2 adsorption and dissociation on the Ti5c site, and thus is expected to be useful to understand the surface reactions on the oxide surface.