乙醇氧化的综合机制和结构敏感性:用于解决复杂反应网络的新过渡状态搜索方法
1Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai, China 200433.
Journal of the American Chemical Society
|July 23, 2008
概括
在 (Pt) 表面上的乙醇氧化是结构依赖的. 开放的Pt{100}表面有效地将乙醇氧化为CO2,而不是Pt{111},它产生部分氧化产品.
科学领域:
- 不同质的催化剂.
- 表面化学 表面化学
- 电触媒溶解是一种电触媒.
背景情况:
- 乙醇对的氧化对直接乙醇燃料电池和生物质转化至关重要.
- 了解反应网络和选择性是催化剂设计的关键.
研究的目的:
- 在不同 (Pt) 表面 (Pt{111}, Pt{211}, Pt{100}) 探索乙醇氧化的反应网络.
- 确定控制乙醇氧化的结构敏感性和选择性的因素,以Pt.
主要方法:
- 利用一种高效的反应路径搜索方法,整合了一种新的过渡状态搜索技术.
- 使用周期密度函数理论 (DFT) 计算.
- 优化了局部最小值以定位表面反应的过渡状态和位点.
主要成果:
- 乙醇对Pt的氧化选择性高度依赖于表面结构.
- 开放的Pt表面 (例如,Pt{100}) 促进C-C键裂变,导致完全氧化到CO2.
- 密集的Pt{111}表面会产生部分氧化产物,如乙甲和酸.
结论:
- 开放的Pt{100} 面对于在低覆盖率下完全氧化乙醇是最佳的.
- 结构选择性源于表面位点的不同能力来结合中间体和稳定基.
- 这些发现解释了Pt四克萨赫德拉纳米晶体在乙醇氧化中的高性能.
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