物理化学学报 >> 2014, Vol. 30 >> Issue (12): 2224-2232.doi: 10.3866/PKU.WHXB201410101

理论与计算化学 上一篇    下一篇

Li和Al掺杂的MgO(001)表面负载W3O9团簇的构型与电子结构

罗云清1, 邱美1, 杨伟1, 朱佳2, 李奕1, 黄昕1, 章永凡1   

  1. 1. 福州大学化学学院, 福州 350116;
    2. 江西师范大学化学化工学院, 南昌 330022
  • 收稿日期:2014-07-28 修回日期:2014-10-10 发布日期:2014-11-27
  • 通讯作者: 章永凡 E-mail:zhangyf@fzu.edu.cn
  • 基金资助:

    国家自然科学基金(21373048, 21371034, 21403094), 福建省杰出青年科学基金(2013J06004)和江西省教育厅(GJJ14261)资助项目

Configuration and Electronic Structure of W3O9 Clusters Supported on Li- and Al-Doped MgO(001) Surfaces

LUO Yun-Qing1, QIU Mei1, YANG Wei1, ZHU Jia2, LI Yi1, HUANG Xin1, ZHANG Yong-Fan1   

  1. 1. College of Chemistry, Fuzhou University, Fuzhou 350116, P. R. China;
    2. College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022, P. R. China
  • Received:2014-07-28 Revised:2014-10-10 Published:2014-11-27
  • Contact: ZHANG Yong-Fan E-mail:zhangyf@fzu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21373048, 21371034, 21403094), Natural Science Foundation of Fujian Province for Distinguished Young Investigator Grant, China (2013J06004), and Fund of Jiangxi Province Office of Education, China (GJJ14261).

摘要:

采用基于第一性原理的分子动力学和量子力学相结合的方法, 对W3O9团簇在经Li 和Al 原子掺杂的MgO(001)表面的负载构型、稳定性以及体系的电子结构进行了系统研究. 结果表明, 当掺杂发生在表层时, 杂质原子的类型对W3O9团簇的负载构型有显著影响. 对于缺电子的Li 掺杂, 负载后W3O9团簇环状构型并不稳定, 转化为链状结构; 而Al 原子的掺杂则使得MgO(001)表面电子富余, 此时W3O9团簇存在平躺和垂直两种吸附方式, 二者能量稳定性相近, 其中前者存在同时与三个W原子成键的帽氧结构. 当掺杂发生在次表层时, 两种掺杂体系W3O9的负载构型相似, 团簇仍保持环状结构并倾向于采用垂直方式沉积在表面上. 与Li 掺杂体系相比, 富电子的Al 掺杂可显著增强W3O9与MgO(001)表面之间的结合能力, 负载后有较多电子从表面转移到团簇中特定的W原子上, 这将对W3O9团簇的催化性能产生显著影响.

关键词: 钨氧化物团簇, 掺杂, MgO表面, 密度泛函理论, 电子结构

Abstract:

The configuration, stability, and electronic structure of W3O9 clusters deposited on Li- and Al-doped MgO(001) surfaces were investigated using first- principles molecular dynamic simulations combined with quantum mechanical calculations. The results indicated that when the doping was in the top layer of the MgO (001) surface, the type of dopant had a great influence on the configuration of theW3O9 clusters. In the presence of electron-deficient Li doping, the cyclic conformation of the gas-phase W3O9 clusters was not stable, and it changed to a chain-like structure. While the introduction of the Al dopant made the surface electron-rich, the W3O9 clusters preferred parallel and vertical arrangements, respectively; the stabilities of the two configurations were similar, except that in the former case the one terminal oxygen of the clusters became a capped oxygen via bonding with three W atoms. When the doping was present in the sublayer, the W3O9 clusters still showed a cyclic conformation, and favored a vertical deposition model. In comparison with the Li-doping of the MgO(001) surface, the Al-doping significantly enhanced the interactions between theW3O9 and the MgO(001) surface, and more electrons were transferred from the substrate to certain W atoms, which would have significant effects on the catalytic performance of the W3O9 clusters.

Key words: Tungsten oxide cluster, Doping, MgO surface, Density functional theory, Electronic structure

MSC2000: 

  • O641