Combined investigation of water sorption on TiO2 rutile (110) single crystal face:: XPS vs. periodic DFT
Combined investigation of water sorption on TiO2 rutile (110) single crystal face:: XPS vs. periodic DFT
复制标题
DOI：
10.1016/j.susc.2006.10.015
复制
发表时间：
2007-01-15
期刊：
影响因子：
1.9
通讯作者：
Catalette, H.
中科院分区：
文献类型：
--
作者：
Perron, H.;Vandenborre, J.;Catalette, H.
用XPS和周期性密度泛函理论计算研究了水在金红石(110)晶面上的吸附。在清洁的和预先暴露在水中的二氧化钛(110)单晶上收集了两组XPS光谱：第一组收集的光电子沿平行于表面的法线方向收集；第二组样品分别倾斜70度。这种倾斜过程促进了来自表面物种的信号，并揭示了第一水合层与表面强烈配位，尽管光谱是在超高真空下记录的，但水分子存在于较高的水合层中。此外，还进行了周期性的密度泛函计算，以研究水的吸附过程，以确定是否发生了分子和/或解离吸附。理论部分的第一步是干表面模型的优化，然后是水吸附的研究。计算的分子水吸附能与以前发表的实验数据相一致，似乎即使它的稳定性稍差，也可以发生解离水吸附。在第二步中，这一假设被考虑在一个更大的表面模型上，其中分子和解离水分子以不同的比例吸附在一起。研究发现，由于氢键的稳定作用，当离解水分子的比例小于33%时，分子水分子和离解水分子可以共存于表面。这些结果与以前的实验工作一致，给出了10%-25%的范围。(C)2006爱思唯尔B.V.保留所有权利。
XPS and periodic DFT calculations have been used to investigate water sorption on the TiO2 rutile (110) face. Two sets of XPS spectra were collected on the TiO2 (110) single crystal clean and previously exposed to water: the first set with photoelectrons collected in a direction parallel to the normal to the surface; and the second set with the sample tilted by 70 degrees, respectively. This tilting procedure promotes the signals from surface species and reveals that the first hydration layer is strongly coordinated to the surface and also that, despite the fact that the spectra were recorded under ultra-high vacuum, water molecules subsist in upper hydration layers. In addition, periodic DFT calculations were performed to investigate the water adsorption process to determine if molecular and/or dissociative adsorption takes place. The first step of the theoretical part was the optimisation of a dry surface model and then the investigation of water adsorption. The calculated molecular water adsorption energies are consistent with previously published experimental data and it appears that even though it is slightly less stable, the dissociative water sorption can also take place. This assumption was considered, in a second step, on a larger surface model where molecular and dissociated water molecules were adsorbed together with different ratio. It was found that, due to hydrogen bonding stabilisation, molecular and dissociated water molecules can coexist on the surface if the ratio of dissociated water molecules is less than approximate to 33%. These results are consistent with previous experimental works giving a 10-25% range. (c) 2006 Elsevier B.V. All rights reserved.