Kinetics and Mechanism of Catalytic Oxidation with Ozone

臭氧催化氧化动力学及机理

• 批准号: 0321979
• 负责人: S. Ted Oyama
• 金额: $ 31万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-15 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0321979&HistoricalAwards=false
• 关键词: Kinetics; Mechanism; Catalytic; Oxidation; Ozone

This proposal deals with the destruction of volatile organic compounds (VOCs) using a novel oxidant, ozone, which is economic at low VOC concentrations and has good potential for practical applications. The research focuses on aspects of fundamental importance in catalysis: the study of mechanism at a molecular level, the treatment of nonuniform surfaces, and the understanding of the origin of reactivity in oxides. The broader impact of the project is addressed in five areas that include 1) high relevancy, 2) advanced training in science, 3) recruitment of minorities, 4) support of undergraduate education, and 5) broad dissemination of results. The aim of the work is to obtain molecular level information about the various steps in the catalytic reactions. The catalysts to be studied will be supported MnOx and VOx, which are highly active catalysts for complete and partial oxidation. These will be characterized by laser Raman spectroscopy (LRS), extended x-ray absorption fine structure (EXAFS) measurements, and ab initio molecular orbital calculations to provide information such as atomic coordination, bond lengths, and vibrational frequencies. The specific substrates will be methanol and acetone, which are commonly used solvents. The mechanism studies will combine rate measurements at a variety of conditions (partial pressure, temperature) together with LRS measurements of adsorbed intermediates and theoretical calculations. Another objective in the present work is to better understand the origin of reactivity enhancement in catalytic oxidation reactions. The hypothesis that will be investigated is whether for alcohol oxidation and ozone decomposition the ability of the catalytic site to accept electrons in the rate-determining step of the reaction is a key determinant of activity. This will be done using near-edge x-ray absorption fine structure (NEXAFS) measurements, which are ideal for obtaining the density of unoccupied electronic states in metal centers, and therefore, to probe the electron-accepting properties of the catalysts.

该建议涉及使用一种新型氧化剂臭氧的挥发性有机化合物（VOC）的破坏，该臭氧是经济浓度低的经济性，并且具有良好的实用应用潜力。 该研究的重点是催化中基本重要性的各个方面：分子水平的机制研究，不均匀表面的处理以及对氧化物反应性起源的理解。 该项目的更广泛影响是在包括1）高相关性的五个领域解决的，2）科学高级培训，3）招募少数族裔，4）支持本科教育和5）成果的广泛传播。这项工作的目的是获得有关催化反应中各个步骤的分子水平信息。 要研究的催化剂将受到MNOX和VOX的支持，它们是用于完整和部分氧化的高活性催化剂。 这些将以激光拉曼光谱法（LRS），扩展的X射线吸收良好结构（EXAFS）测量以及AB INLIO算分子轨道计算为特征，以提供原子配位，键长和振动频率等信息。 特定的底物将是甲醇和丙酮，它们是通常使用的溶剂。 该机理研究将在多种条件（部分压力，温度）下结合速率测量，以及吸附的中间体的LRS测量和理论计算。 本工作的另一个目标是更好地了解催化氧化反应中反应性增强的起源。 将要研究的假设是对于酒精氧化和臭氧分解，催化位点在反应的速率确定步骤中接受电子的能力是否是活性的关键决定因素。 这将是使用近边缘X射线吸收精细结构（NEXAFS）测量值进行的，这是获得金属中心中无占电子状态的密度的理想之选，因此可以探测催化剂的电子感知特性。