催化学报

催化学报 ›› 2010, Vol. 31 ›› Issue (8): 1013-1018.DOI: 10.1016/S1872-2067(10)60102-7

• 研究论文 • 上一篇    下一篇

单层 FeO 薄膜表面周期性氧缺陷结构的形成

马腾, 傅强, 姚运喜, 崔义, 谭大力, 翟润生, 包信和   

  1. 中国科学院大连化学物理研究所催化基础国家重点实验室, 辽宁大连 116023
  • 收稿日期:2010-05-04 出版日期:2010-08-30 发布日期:2013-12-26
  • 通讯作者: 傅强

Formation of Periodic Arrays of O Vacancy Clusters on Monolayer FeO Islands Grown on Pt(111)

MA Teng, FU Qiang#, YAO Yunxi, CUI Yi, TAN Dali, ZHAI Runsheng, BAO Xinhe*   

  1. State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
  • Received:2010-05-04 Online:2010-08-30 Published:2013-12-26

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被引次数

1

摘要： 采用扫描隧道显微镜和 X 射线光电子能谱对含有次表层 Fe 的 Pt 表皮结构 (Pt skin), 即 0.4 ML Fe 的 Pt/Fe/Pt(111) 表面, 在 1.1 × 10?7 kPa 氧气气氛退火过程中的变化进行了研究. 结果表明, 当退火温度为 600 K 时, 氧气在 Pt/Fe/Pt(111) 表面上解离吸附并诱导表面局域结构的重构; 750 K 时次表层 Fe 可以扩散到表面并被氧化; 当升至 850 K 时, 在样品表面形成单层 FeO 结构, 并且 FeO 表面具有周期性的缺陷. 这种缺陷是由于单层 FeO 薄膜的摩尔条纹单胞中 fcc 位上一个或多个氧原子缺失形成的, 其中多原子空位被确定为缺失 6 个氧原子所致. FeO 表面缺陷结构的研究为理解 Fe-Pt 催化剂在氧化气氛中的结构稳定性以及构造表面活性位提供一定的基础.

关键词: 铁, 铂, 双金属催化剂, 氧化亚铁薄膜, 氧空位缺陷, 扫描隧道显微镜

Abstract: The structural evolution of a Pt surface with 0.4 monolayer (ML) subsurface Fe on annealing in 1.1 × 10?7 kPa O2 was studied by scanning tunneling microscopy and X-ray photoelectron spectroscopy. When the annealing temperature was 600 K, only dissociative adsorption of O2 occurred, which induced the local restructuring of surface regions. At 750 K, subsurface Fe atoms segregated onto the surface and were oxidized. When the annealing temperature was increased to 850 K, well defined monolayer FeO islands with periodic arrays of defects were formed. The defects were located at the hexagonal closest packed sites (fcc) of FeO Moiré unit cells and were either single oxygen vacancies or multiple oxygen vacancies consisting of six missing O atoms. The formation of periodic defects on monolayer FeO islands may be a way to construct active sites on Pt-Fe model catalysts.

Key words: iron, platinum, bimetallic catalyst, iron oxide film, oxygen vacancy, scanning tunneling microscopy