Metal-Support Effects in Platinum/Zeolite-L Catalysts

本文用物理和化学相结合的方法研究了铂/沸石-L催化剂中金属与载体的相互作用。尝试用X射线吸收(近边(XANES)和精细结构(EXAFS)光谱)和氢-1和碳-13的核磁共振表征铂颗粒与L沸石之间的相互作用。这些研究的结果与催化活性和化学吸附有关，涉及氢、氧、一氧化碳、苯和甲苯。所使用的测试反应包括C-6烷烃的异构化和氢解，苯-甲苯混合物的竞争加氢，以及巴豆醛的选择性加氢。为了提供参考，其中许多测量也将使用Y型沸石上的铂和二氧化硅上的铂进行。这些反应研究是与阿根廷马德普拉塔大学的丹尼尔·雷萨斯科博士合作完成的。以L沸石为基础、含铂族金属的催化剂是炼油厂汽油改质的最新一代重整催化剂。石油和催化剂公司都在积极寻找新的配方，但系统的研究很少。这项工作不仅阐明了这些系统是如何工作的，而且可能直接导致改进的配方。

This is an investigation of metal-support interactions in platinum/zeolite-L using a combination of physical and chemical probes. Attempts are made to characterize the interactions between platinum particles and zeolite-L using X- ray absorption (both near-edge (XANES) and fine-structure (EXAFS) spectroscopies) and nuclear magnetic resonance of hydrogen-1 and carbon-13. Results of these studies are correlated with catalytic activity and chemisorption involving hydrogen, oxygen, carbon monoxide, benzene, and toluene. Test reactions used include the isomerization and hydrogenolysis of C-6 alkanes, competitive hydrogenation of benzene-toluene mixtures, and selective hydrogenation of crotonaldehyde. To provide points of reference, many of these measurements will also be done using platinum on zeolite-Y and platinum on silica. The reaction studies are done in collaboration with Dr. Daniel Resasco of the University of Mar del Plata in Argentina. Catalysts based on zeolite-L and containing platinum-group metals represent the newest generation of reforming catalysts used to upgrade gasoline in refineries. Both oil and catalyst companies are actively seeking new formulations, but systematic studies are rare. This work not only sheds light on how these systems work, but could possibly lead directly to improved formulations.