催化学报

催化学报 ›› 2010, Vol. 31 ›› Issue (1): 24-32.

• 研究论文 • 上一篇    下一篇

Pt(111) 表面上表层 Fe (FeO) 结构和次表层 Fe 结构的可控转变

马腾, 傅强, 崔义, 张镇, 王珍, 谭大力, 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:2010-01-25 出版日期:2010-01-25 发布日期:2010-01-25

Controlled Transformation of the Structures of Surface Fe (FeO) and Subsur-face Fe on Pt(111)

MA Teng, FU Qiang#, CUI Yi, ZHANG Zhen, WANG Zhen, TAN Dali, BAO Xinhe*   

  1. State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
  • Received:2010-01-25 Online:2010-01-25 Published:2010-01-25

PDF

585

被引次数

3

摘要： 利用扫描隧道显微镜 (STM) 和 X 射线光电子能谱 (XPS) 对 Pt(111) 表面制备的 Fe 单层薄膜及其在不同环境气氛条件下的多种结构进行了研究. 在温度为 487 K 的 Pt(111) 表面制备出了完整的 Fe 单层薄膜Fe/Pt(111). 对 Fe/Pt(111) 依次升高温度进行超高真空退火, STM 和 XPS 结果表明退火温度高于 800 K 时, 表面 Fe 原子扩散到次表层区域, 形成次表层 Fe 结构Pt/Fe/Pt(111). Pt/Fe/Pt(111) 在 O2 氧化气氛中经 850 K 退火可转变成表面 FeO 薄膜FeO/Pt(111). FeO/Pt(111) 结构在温和的 H2 还原气氛中 (600 K) 转变成表面 Fe 结构, 进一步的还原处理 (800 K) 则可以重新生成 Pt/Fe/Pt(111). 控制样品的环境气氛在 O2 和 H2 之间切换, 使得表面 Fe (FeO) 和次表面 Fe 可以重复地转变. 本研究实现了多种 Fe-Pt 表面结构的可控制备, 可为合理地设计高效、价廉的催化剂提供借鉴.

关键词: 双金属催化剂, 氧化物, Pt 富集表面, 反相模型体系

Abstract: Monolayer Fe films on Pt(111) and their derived structures under different environments were investigated by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). The growth of monolayer Fe films was seen at 487 K. The surface composition and structure of the Fe/Pt(111) surface were monitored by XPS and STM during stepwise annealing under vacuum. Surface Fe was driven into the subsurface region during annealing above 800 K. This resulted in a Pt-skin surface of Pt/Fe/Pt(111). Oxidation of the Pt-skin structure in O2 produced a FeO surface structure, FeO/Pt(111). This was transformed into a surface Fe structure by mild reduction in H2 (600 K) and into subsurface Fe by further severe reduction (800 K). The transformation of surface Fe (FeO) and subsurface Fe in Pt(111) was reversible in cycled oxidation and reduction treatments. The results demonstrated the controlled preparation of various Fe-Pt surfaces. This can be important for the design of high-performance and low-cost catalysts.

Key words: bimetallic catalyst, oxide, platinum-skin, inverse model system