物理化学学报 >> 2011, Vol. 27 >> Issue (04): 851-857.doi: 10.3866/PKU.WHXB20110405

理论与计算化学 上一篇    下一篇

Cux (x=1-4)团簇在CeO2(111)表面的吸附

杨宗献1,2, 谢罗刚1   

  1. 1. 河南师范大学物理与信息工程学院, 河南 新乡 453007;
    2. 河南省光伏材料重点实验室, 河南 新乡 453007
  • 收稿日期:2010-12-20 修回日期:2011-01-14 发布日期:2011-03-29
  • 通讯作者: 杨宗献 E-mail:yzx@henannu.edu.cn
  • 基金资助:

    国家自然科学基金(10674042)和河南省科技创新杰出人才计划(104200510014)资助项目

Adhesion of Small Cux (x=1-4) Clusters on a CeO2(111) Surface

YANG Zong-Xian1,2, XIE Luo-Gang1   

  1. 1. College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007, Henan Province, P. R. China;
    2. Henan Key Laboratory of Photovoltaic Materials, Xinxiang 453007, Henan Province, P. R. China
  • Received:2010-12-20 Revised:2011-01-14 Published:2011-03-29
  • Contact: YANG Zong-Xian E-mail:yzx@henannu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (10674042) and Innovation Scientists and Technicians Troop Construction Projects of Henan Province, China (104200510014).

摘要:

用基于密度泛函理论的第一性原理方法研究了Cu团簇(Cux, x=1-4)在CeO2(111)表面的吸附. 研究发现当团簇比较小时(x=2, 3), 倾向于平铺表面; 当x=4时, Cu团簇在CeO2(111)表面以三维的四面体结构吸附较为稳定, 从Cu 3d到Ce 4f的电荷转移使Cu团簇带正电荷. 由二维的菱形结构到三维的四面体结构的转变势垒为1.05 eV, 并且其中一个Cu原子直接迁移到另外三个Cu原子的空位顶部的转变路径比较有利. 在Cu团簇与CeO2的相互作用过程中, Cu-O和Cu-Cu相互作用的竞争最终决定了Cu团簇在CeO2上的形貌. 这种CeO2(111)负载的带正电的三维Cu团簇将对水分解, 进而对水煤气反应具有高的催化活性.

关键词: 密度泛函理论, Cu团簇, 吸附, Cux/CeO2(111)

Abstract:

We investigated the adhesion behavior of Cu clusters (Cux, x=1-4) on a CeO2(111) surface using first-principles density functional theory (DFT). We found that small Cux clusters (x=2, 3) tended to adhere as two dimensional (2D) planar structures on the CeO2(111) surface. For the Cu4 cluster, a three dimensional (3D) tetrahedral structure is preferred and the 3D Cu4 particle is positively charged because of charge transfer from Cu 3d to Ce 4f. The transition from a 2D planar structure to 3D particles occurs with a transition barrier of 1.05 eV and the favorable route consists of one Cu atom hopping directly from the interface site to the hollow site above the Cu triangle. Because the Cu-O interactions are comparable with the Cu-Cu intra-cluster interactions, their competition determines the morphologies of the eventual Cu clusters on CeO2. The 3D positively charged Cu4 particle obtained on CeO2 is expected to result in distinct catalytic performance compared to the unsupported Cu4 cluster for water dissociation, and thus the water gas shift reactions.

Key words: Density functional theory, Cu cluster, Adhesion, Cux/CeO2(111)

MSC2000: 

  • O641