Cu_x(x=1-4)团簇在CeO_2(111)表面的吸附(英文)  

Adhesion of Small Cu_x (x=1-4) Clusters on a CeO_2(111) Surface

作　　者：杨宗献[1,2] 谢罗刚[1] 

机构地区：[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

出　　处：《物理化学学报》2011年第4期851-857,共7页Acta Physico-Chimica Sinica

基　　金：supported by the National Natural Science Foundation of China(10674042);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.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.

关 键 词：密度泛函理论 Cu团簇 吸附 Cux/CeO2(111) 

分 类 号：O647.3[理学—物理化学]