碳掺杂TiO_2(101)晶面上水的吸附和解离

Adsorption and Splitting of Water on(101) Surface of Carbon-doped Anatase Titania

运用密度泛函理论研究了未掺杂、体相掺杂和表层掺杂碳的锐钛矿型二氧化钛(101)晶面(TiO_2(101))上水吸附及其分解动力学。结果表明:分子态水在3种表面上吸附结构比解离态的吸附结构更稳定,说明水在这3种表面上自发解离在热力学上是不允许的。进一步对3种表面上水解离的动力学研究表明:表面掺杂碳的TiO_2(101)上水解离的势垒最低,水在这个面上解离速度最快。这归因于表面碳掺杂对TiO_2(101)面的表层结构有很大影响。

The adsorptioia and the splitting dynamics of water on the TiO2 （101） surface were investigated in the pure, bulk carbon-doped and surface carbon-doped states using density functional theory. The results indicated that the adsorption structures of molecular water on three surfaces were more stable than the corresponding structures of dissociated water. This implied that the spontaneous dissociation of water on these surfaces was not thermodynamically favored. Furthermore, the dynamical analysis of the water splitting on these surfaces demonstrated that the dissociation of water had the smallest energy barrier on the surface carbon-doped TiO2（ 101 ） among three surfaces, indicating the fastest dissociation of water on this surface. This phenomenon could be attributed to the influences of surface carbon-doping on the surface structure of TiO2 （ 101 ）.