Kajita Seiji, Minato Taketoshi, Kato Hiroyuki S, Kawai Maki, Nakayama Takashi
Surface Chemistry Laboratory, RIKEN (Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
J Chem Phys. 2007 Sep 14;127(10):104709. doi: 10.1063/1.2768951.
Density functional calculations are performed to study the H-atom diffusion on titanium dioxide (110) surface in the cases of water-molecule dissociation and splitting of the adjacent hydroxyl OH pair. It is shown that, when a water molecule is adsorbed at a surface oxygen-vacancy site, a fragment H atom of the water molecule tends to diffuse toward the nearest-neighboring bridging-oxygen sites by using a straight-line or relay-point path. As the result, a pair of surface hydroxyl OH is formed on the same oxygen row. In a thermal process, on the other hand, such OH pair favorably splits only by using a relay-point path, i.e., by transferring one H atom from a bridging-oxygen site to a next-neighboring one along the same oxygen row by way of another in-plane oxygen site. We found that the latter splitting reaction is activated around room temperature.
进行密度泛函计算以研究在水分子解离和相邻羟基OH对分裂的情况下氢原子在二氧化钛（110）表面上的扩散。结果表明，当一个水分子吸附在表面氧空位处时，水分子的一个氢原子片段倾向于通过直线或中继点路径扩散到最近邻的桥氧位点。结果，在同一氧行上形成了一对表面羟基OH。另一方面，在热过程中，这种OH对仅通过中继点路径有利地分裂，即通过将一个氢原子从桥氧位点沿着同一氧行通过另一个面内氧位点转移到相邻的下一个位点。我们发现后者的分裂反应在室温左右被激活。
