Adsorption and Reaction Sites on Supported Metal Catalysts

本项目的目标是确定和表征负载型金属催化剂上加氢反应的活性中心，并确定活性中心的浓度和活性与催化剂的物理性质的关系。这包括确定氧化物载体上是否发生氢化，金属和氧化物上位置之间的转移速率，过程中的限制步骤，以及这些因素如何依赖于催化剂的性质和制备方式。采用程序升温反应、程序升温脱附、同位素标记、瞬时同位素训练和红外光谱等方法研究了负载型铂、钯催化剂上的多个反应中心。被氢化的底物包括吸附的甲氧基和吸附的有机物。采用了一系列催化剂制备方法，对催化剂进行了氢化学吸附、比表面积测量、X射线光电子能谱和原子吸收等表征。这个项目考察了类似于工业中使用的系统中加氢反应的基本方面。虽然这项研究不是针对任何特定的应用，但它可以在许多情况下导致工业加氢的改进。这种工艺在特种化工、制药、食品加工和石油行业中很常见。

The objectives of this project are to identify and characterize the active sites for hydrogenation reactions on supported metal catalysts and to determine the dependence of the concentration and activity of the active sites on the physical properties of the catalyst. This involves determining whether hydrogenation occurs on the oxide support, the rates of transfer between sites on the metal and on the oxide, what the limiting steps in the process are, and how these factors depend on the properties and mode of preparation of the catalysts. Temperature-programmed reaction, temperature-programmed desorption, isotopic labelling, transient isotope training, and infrared spectroscopy are used to study multiple reaction sites on supported platinum and palladium catalysts. Substrates to be hydrogenated include adsorbed methoxy and adsorbed organics. A series of catalyst preparations is used, with the catalysts characterized by hydrogen chemisorption, surface-area measurements, X-ray photoelectron spectroscopy, and atomic absorption. This project examines fundamental aspects of hydrogenation reactions in systems similar to those used in industry. Although the study is not directed to any particular application, it could lead to improvement in industrial hydrogenation in many contexts. Such processes are common in the specialty chemical, pharmaceutical, food processing, and petroleum industries.