水在金红石型TiO_2(110)表面<001>阶梯边缘吸附的第一性原理研究  

A First-principles study of water adsorption at ＜001＞ step edge on rutile TiO_2(110) surface

作　　者：洪峰[1] 徐文娟[1] 倪宇恒 马忠权[1] 李拥华[1] 徐飞[1] 

机构地区：[1]上海大学理学院物理系索朗光伏材料与器件R&D联合实验室,上海200444

出　　处：《中国科学：化学》2012年第6期806-814,共9页SCIENTIA SINICA Chimica

基　　金：国家自然科学基金项目(60876045;11104117)资助

摘　　要：利用第一性原理计算方法,研究了水在金红石型TiO2(110)表面及<001>阶梯边缘处的吸附.关于水在(110)表面上的吸附,研究表明,对不同的吸附率,水都是以分子模式吸附在表面.关于水在<001>阶梯边缘处的吸附,研究表明,其吸附模式和吸附率有密切的联系.当水的吸附率为一个单层(1ML)时,分子吸附和解离吸附对应的吸附能分别为0.92和0.60eV,分子吸附模式更稳定.当吸附率降为1/2ML时,分子吸附和解离吸附所对应的吸附能分别为0.86和0.84eV,两种吸附模式都可能存在.在表面上,不同吸附模式的吸附能随吸附率变化趋势是一致的.而在<001>阶梯边缘处,对于不同的吸附模式,吸附能随吸附率的变化呈现出不同的变化趋势.这是由在<001>阶梯边缘处低吸附率时解离模式的独特结构引起的.Water adsorption on rutile TiO2 （110） surface, as well as 〈001〉 step edges has been investigated using first principles calculations. For water on （110） surface, we find that the molecular adsorption is more stable at all coverage. When water adsorbs on the intrinsic 〈001〉 step edge, the adsorbed mode depends strongly on the water coverage. At 1 ML of water coverage, the adsorption energies, 0.92 and 0.60 eV for molecular and dissociative adsorption respectively, are obtained. While with water coverage decreasing to 1/2 ML, the molecular and dissociative adsorptions have very similar energies, 0.86 and 0.84 eV, respectively. Therefore, the qualitative trend of the adsorption energy with water coverage for both adsorption modes exhibits a very different behavior. We find that this unusual behavior is mainly induced by the unique atomic configuration of dissociative adsorption at 1/2 ML.

关 键 词：二氧化钛 水 吸附 阶梯 第一性原理 

分 类 号：O647.31[理学—物理化学]