Metal-Support Effects in Platinum/Zeolite-L Catalysts

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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.