In-Situ Extended X-Ray Absorption Fine Structure Study of Chemical Promoters in Catalysis

催化化学促进剂的原位扩展X射线吸收精细结构研究

• 批准号: 8715541
• 负责人: James Goodwin, Jr.
• 金额: $ 24.45万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-05-01 至 1991-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8715541&HistoricalAwards=false
• 关键词: Situ; Extended; Ray; Absorption; Fine

The interaction of alkali-metal promoters with supported rhodium catalysts is studied using extended X-ray absorption fine structure (EXAFS). By use of an in-situ EXAFS cell, it is possible to observe the nature and diversity of the alkali-metal and transition-metal atoms both in the reduced catalysts and under reaction conditions. These data are combined with results of catalyst characterization by atomic absorption, X-ray diffraction, gas adsorption, infrared spectroscopy, and thermal desorption, as well as transient kinetic studies, on the same catalysts to define the bonding, electronic state, nearest neighbors, and local structure of both the promoter and the catalytic metal. Chemical modification of catalysts by the addition of small quantities of a promoter can greatly affect catalyst activity and selectivity. Many fundamental questions about how promoters function remain unanswered, including where they are located on the surface, what relationship they have with the support, and what interactions they have with the reactants. These questions are addressed using a combination of EXAFS, transient kinetics, and more traditional techniques. This could lead to a general theory of surface chemical promotion.

碱金属助剂与负载铑的相互作用 用扩展X射线吸收精细 结构（EXAFS）。 通过使用现场EXAFS池， 可以观察到碱金属的性质和多样性 和过渡金属原子， 在反应条件下。 这些数据与结果相结合 通过原子吸收、X射线、 衍射、气体吸附、红外光谱和热分析 解吸，以及瞬态动力学研究，在同一 催化剂来定义键合，电子状态，最近的 邻居，以及启动子和启动子的局部结构。 催化金属 通过添加少量的 助催化剂的量可极大地影响催化剂活性， 选择性 关于发起人如何 功能仍未得到解答，包括它们位于何处 表面，它们与支撑物的关系， 它们与反应物之间的相互作用。 这些问题 使用EXAFS，瞬态动力学， 更传统的技术。 这可能会导致一个将军 表面化学促进理论