支持黄金的催化:CO氧化和黄金氧化状态的催化活性之间的相关性
1Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616, USA.
Journal of the American Chemical Society
|March 5, 2004
概括
这项研究表明,黄金是MgO支持的黄金催化剂中CO氧化催化剂的关键. 黄金集群大小没有影响活动,但黄金存在与催化性能相关.
科学领域:
- 不同质的催化剂.
- 表面科学是一门科学.
- 材料化学 材料化学
背景情况:
- 支持MgO的黄金催化剂正在研究CO氧化.
- 了解黄金催化中的活性位点对于开发高效的催化剂至关重要.
研究的目的:
- 阐明黄金氧化状态和集群大小在MgO支持的黄金对CO氧化的催化活性中的作用.
- 为了确定负责催化活动的特定黄金物种.
主要方法:
- 采用X射线吸收近边结构 (XANES) 谱法来确定黄金的氧化状态.
- 温度编程氧化 (TPO) 和还原 (TPR) 用于研究催化剂表面反应.
- 扩展的X射线吸收细结构 (EXAFS) 光谱分析黄金集群大小.
主要成果:
- 在工作催化剂中检测到黄金(I) 和黄金(0) 两种物种.
- 黄金集群大小在样本中一致 (约为30 Å),与催化活性没有相关性.
- 催化活性和表面黄金度随着CO部分压力的增加而下降,伴随着黄金形成的增加.
结论:
- 支持MgO的黄金用于CO氧化的催化活性主要归因于黄金 (I) 种.
- 黄金集群的大小不是决定该系统活动的决定因素.
- 活跃的催化场所含有黄金.
相关概念视频
Cofactors and Coenzymes
Enzymes require additional components for proper function. There are two such classes of molecules: cofactors and coenzymes. Cofactors are metallic ions and coenzymes are non-protein organic molecules. Both of these types of helper molecule can be tightly bound to the enzyme or bound only when the substrate binds.
Catalysis
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
Properties of Organometallic Compounds
Organometallic compounds are compounds that contain a carbon–metal bond. Carbon belongs to an organyl group like alkyl, aryl, allyl, or benzyl groups. The metal can be from Group I or Group II of the periodic table, a transition metal, or a semimetal.
Cofactors and Coenzymes
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Cofactors can be metallic ions or organic molecules called coenzymes. These types of helper...
Cofactors can be metallic ions or organic molecules called coenzymes. These types of helper...
Catalysis
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Heterogeneous Catalysis
Heterogeneous catalysis involves a catalyst in a different phase from the reactants. It is a process where the catalyst and the reactants are in distinct phases, typically solid and gas or liquid.Most heterogeneous catalysts are metals, metal oxides, or acids. The list includes transition metals like iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), manganese (Mn), tungsten (W), silver (Ag), and copper (Cu). These metals possess partially vacant d orbitals that...


