电荷状态对含有基氧中心的金属氧化物集群中的催化氧化反应的影响
Grant E Johnson1, Roland Mitrić, Melanie Nössler
1Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Journal of the American Chemical Society
|April 2, 2009
概括
阳离子氧化集群 (Zr(x) O(2x+1)) (((-) 具有独特的反应性,氧化CO和关联乙烯,与它们的阴离子对应物不同. 电荷状态显著影响这些金属氧化物集群中的催化活性和反应通路.
科学领域:
- 表面科学是一门学科.
- 催化剂是一种催化剂.
- 计算化学计算化学
背景情况:
- 氧化集群正在研究催化应用.
- 了解电荷状态对集群反应性的影响,对于催化剂设计至关重要.
研究的目的:
- 为了合成和表征离子氧化集群 (Zr(x) O(2x+1)) ((-) (x = 1-4).
- 为了比较这些阴离子集群的活性与以前研究的阴离子集群 ((ZrO(2)) ((x) ((+)).
- 阐明电荷状态和电子结构在催化氧化和分子协会中的作用.
主要方法:
- 导向离子束质谱实验被用于集群合成和表征.
- 密度函数理论 (DFT) 的计算被用来研究反应机制和电子性质.
- 对金属-氧键长度和静电电位的分析为反应性提供了洞察力.
主要成果:
- 阴离子集群 (Zr(x) O(2x+1)) (((-) 与基氧中心和延长的金属-氧键形成.
- 阳离子集群强烈氧化一氧化碳和相关的乙,但乙烯较弱.
- 阴离子团 ((ZrO(2)) ((x) ((+)) 显示了所有三个分子的高活性.
- 乙烯和乙烯氧化过程中的转移对阳离子有利,但对阳离子不利.
- 静电电位分析揭示了基于电荷状态的核友分子相互作用的差异.
结论:
- 氧化集群的电荷状态极大地影响了它们的催化活性和选择性.
- 阳离子集群可以再生,使CO氧化过程中的多个催化循环成为可能.
- 了解这些取决于电荷的效应是设计高效异质催化剂的关键.
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