Fundamental Studies of Metal Dispersion for Uniformly and Nonuniformly Distributed Catalysts

均匀和非均匀分布催化剂金属分散的基础研究

• 批准号: 8709019
• 负责人: John Regalbuto
• 金额: $ 7万
• 依托单位: University of Illinois at Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-09-01 至 1990-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8709019&HistoricalAwards=false
• 关键词: Fundamental; Studies; Metal; Dispersion; Uniformly

The objective of this project is to establish a scientific basis for the prediction of catalyst dispersion from fundamental studies of the impregnation step of catalyst preparation. Techniques must first be developed for this new approach. Experiments will be designed in which the number of coupled elementary processes of impregnation is minimized. Thus, the first type of system to be studied will be adsorption over a planar substrate. A high-resolution electron microscopy technique will be employed with a special "cold stage" to enable direct, detailed observation of catalyst precursor morphology just after impregnation. A second scheme will be designed for strongly adsorbing systems to permit measurement of an adsorption isotherm from the liquid phase (by atomic adsorption) and measurement of dispersion directly from the solid phase (by chemisorption and possibly TEM) for the same catalyst batch. A third apparatus will be designed to investigate the variation of dispersion with position in nonuniformly distributed catalysts. Different one-dimensional distribution profiles will be produced in an elongated catalyst sample, containing sufficient material so that the bulk metal concentration and metal dispersion can be measured for discrete sections along the sample length. In all cases, direct measurements of catalyst dispersion will be compared to existing impregnation theory. Finally, revised theory will be developed where needed, using as a basis these relatively simple impregnation systems. These studies are intended to provide a background to design of catalyst system preparation procedures that would give predictable results, in contrast to the trial-and-error methods now in use.

本项目的目的是通过对催化剂制备过程中浸渍步骤的基础性研究，为催化剂分散性的预测提供科学依据。必须首先为这种新方法开发技术。设计的实验将使浸渍的耦合基本过程的数量最小化。因此，要研究的第一类系统将是在平面衬底上的吸附。高分辨率电子显微镜技术将与特殊的“冷阶段”一起使用，以便能够直接、详细地观察浸渍后催化剂前体的形态。第二个方案将设计用于强吸附系统，以允许测量同一批催化剂的液相吸附等温线(通过原子吸附)和直接从固相分散(通过化学吸附和可能的透射电子显微镜)。第三个装置将被设计用来研究非均匀分布催化剂中分散度随位置的变化。在加长的催化剂样品中将产生不同的一维分布曲线，其中包含足够的材料，以便可以测量沿样品长度的离散部分的整体金属浓度和金属分散度。在所有情况下，催化剂分散性的直接测量将与现有的浸渍理论进行比较。最后，将在需要的地方发展修正的理论，使用这些相对简单的浸渍系统作为基础。这些研究旨在为催化剂系统制备程序的设计提供一个背景，这些程序将提供可预测的结果，而不是目前使用的反复试验的方法。