在Pt上的CO氧化过程中,各种氧化物和化学吸收的氧气的不同反应性111)
Daniel Miller1, Hernan Sanchez Casalongue, Hendrik Bluhm
1SUNCAT Center for Interface Science and Catalysis and §Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , 2575 Sand Hill Rd, Menlo Park, California 94025, United States.
Journal of the American Chemical Society
|April 9, 2014
概括
氧气覆盖的 (Pt) 表面对一氧化碳 (CO) 的反应性随着氧气覆盖面的增加而降低. 化学吸收氧气 (Oad) 是最有反应性的,而二氧化 (α-PtO2) 表面是惰性的.
科学领域:
- 表面科学是一门学科.
- 催化剂是一种催化剂.
- 材料科学 材料科学 材料科学
背景情况:
- (Pt) 表面是各种化学反应中的关键催化剂.
- 了解表面氧对Pt反应性的作用对于优化催化过程至关重要.
研究的目的:
- 为了研究不同覆盖氧气的Pt(111) 表面对一氧化碳 (CO) 的反应性.
- 确定不同氧气覆盖和氧气相如何影响CO吸附和对Pt的反应.
主要方法:
- 使用X射线光电子光谱 (XPS) 分析表面成分和氧化状态.
- 极化分辨率的OK边缘X射线吸收光谱 (XAS) 提供了对氧物种电子结构和结合的洞察.
主要成果:
- 表面对二氧化碳的反应性随着Pt上氧气覆盖率的增加而单调地降低了.
- 化学吸收氧 (Oad) 的反应性最高,而α-PtO2三层的反应性最低.
- 111) 完全覆盖着α-PtO2的表面被发现对CO无效.
结论:
- 反应性氧物种可能是化学吸收氧 (Oad) 或类似PtO的表面氧化物.
- 二氧化 (α-PtO2) 充当观众物种,其存在使Pt表面对CO.
- 优化催化活性可能涉及控制氧气覆盖,以有利于反应性Oad或PtO类相.
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