Studies of Zeolite Catalysts of Control of Emissions: RedoxReactions and Cation Siting

这是一项过渡金属交换成沸石或含硅磷酸铝分子筛（SAPOs）作为氧化还原反应催化剂的研究。所研究的沸石包括富硅的faujasites和其他大孔沸石，如沸石L和沸石omega。动力学的反应，如还原一氧化氮与一氧化碳或氨，分解一氧化二氮和甲烷的部分氧化进行了检查。重点放在这些材料中过渡金属阳离子的配位环境如何与它们的催化行为相关。动力学测量与涉及同位素示踪剂的研究相结合，这些发现与阳离子与各种吸附质分子相互作用的光谱和量热研究相结合。目的是确定交换阳离子的位置及其与沸石（或SAPO）基质、吸附气体和其他共交换金属阳离子的相互作用性质。所用的光谱学技术包括高场魔角核磁共振、红外光谱学（包括中程和远程）和穆斯堡尔光谱学。正在处理的问题具有相当重要的根本意义。此外，所研究的系统可以直接应用于各种工业环境中的部分氧化，甲烷固定，汽车排放控制和酸雨改善。这是威斯康星大学密尔沃基分校和麦迪逊分校的合作成果。

This is a study of transition metals exchanged into zeolites or into silicon-containing aluminophosphate molecular sieves (SAPOs) as catalysts for redox reactions. The zeolites studied include silicon-enriched faujasites and other large-pore zeolites such as zeolite L and zeolite omega. The kinetics of reactions such as the reduction of nitric oxide with carbon monoxide or ammonia, the decomposition of nitrous oxide, and the partial oxidation of methane are examined. Emphasis is placed on how the coordination environments of the transition-metal cations in these materials are related to their catalytic behavior. Kinetic measurements are combined with studies involving isotopic tracers, and these findings are coupled with spectroscopic and calorimetric studies of the interactions of the cations with various adsorbate molecules. A goal is to determine the sitings of exchanged cations and the natures of their interactions with the zeolite (or SAPO) matrix, adsorbed gases, and other coexchanged metal cations. Spectroscopic techniques used include high-field magic-angle nuclear magnetic resonance, infrared spectroscopy (both midrange and far range), and Moessbauer spectroscopy. The issues being addressed are of considerable fundamental importance. In addition the systems under investigation may have direct application in partial oxidation in a variety of industrial settings, fixation of methane, automotive emission control, and acid rain amelioration. This is a collaborative effort between the Milwaukee and Madison campuses of the University of Wisconsin.