吸附在TiO2(110)表面的Aun-1Ag(n=1-5)团簇的第一性原理研究  

A First Principles Study on Au_(n-1)Ag(n=1-5)Clusters Adsorbed on TiO_2(110)Surface

作　　者：杨广丽[1] 岳瑞英 赵健[1] 朱小蕾[1] 

机构地区：[1]南京工业大学化学化工学院,材料化学工程国家重点实验室,江苏南京210009

出　　处：《南京师大学报（自然科学版）》2016年第2期38-43,共6页Journal of Nanjing Normal University(Natural Science Edition)

基　　金：国家自然科学基金项目(21276122、21136001、91434109)

摘　　要：采用第一性原理对Au_(n-1)Ag(n=1-5)团簇所有异构体吸附在TiO_2(110)表面的负载构型进行了结构优化,并分析了负载团簇的最稳定结构的电子性质.研究结果表明:在较稳定的吸附构型中,团簇都与TiO_2表面的两配位的氧(O_(2c))相连接.将不稳定的Au3Ag异构体负载在TiO_2表面后稳定性明显提高.能量分析表明,负载的Au_3Ag为最稳定体系.根据bader电荷和DOS分析,吸附Au_(n-1)Ag(n=1-5)团簇后,有电子从金属团簇转移到吸附基底上.Au_(n-1)Ag(n=4,5)团簇吸附后的TiO_2(110)表面不再具有半导体性质.Au Ag和Au_2Ag团簇与TiO_2表面的作用较弱,它们与TiO_2表面之间的电荷转移较少.All possible isomers of Aun-1Ag （n= 1-5）supported on TiO2 surface are optimized and electronic properties of the supported most-stable metal clusters are analyzed based on the first-principles density functional theory. The results show that in the most stable configurations, the metal clusters combine with the two-coordinated oxygen （O2c）of the TiO2 surface. The stability of unstable Au3Ag isomer is significantly improved by supporting it on the TiO2 surface. Energy analyses demonstrate that the supported Au3Ag is most stable cluster among the supported Aun-1Ag（n=1-5）clusters. The analyses of charge and density of state（DOS）reveal that there is obvious charge transfer from metal cluster to substrate after the cluster adsorption on the surface of TiO2. The TiO2（110）surfaces don＇t have the semiconducting character for TiO2- Aun-1Ag（n=4,5）systems. There are weaker interactions and few charge transfer between AuAg/Au2Ag and the TiO2 surface.

关 键 词：双金属团簇 Ti O2表面 吸附 密度泛函理论 态密度 

分 类 号：O641.1[理学—物理化学]