Understanding sulfur poisoning of bimetallic Pd-Pt methane oxidation catalysts and their regeneration

Applied Catalysis B: Environmental Journal

Pd-Pt/Al₂O₃ and Pd-Pt/CeO₂-ZrO₂-Y₂O₃-La₂O₃ methane oxidation catalysts were investigated under typical lean-burn gas engine conditions with respect to sulfur poisoning and during reactivation, particularly under the most efficient rich conditions. Sulfation of the noble metal and the support material led to pronounced catalyst deactivation. A pronounced transfer of sulfates to the support, particularly alumina, only partially protects the noble metal. In situ X-ray absorption spectroscopy gave insight into the nature and evolution of Pd species during regenerative treatment. Although palladium sulfate that formed during poisoning is decomposed at approximately 200°C in oxygen-free conditions, support regeneration requires higher temperatures, which result in PdS formation above 400°C. Despite its high stability under rich conditions, PdS decomposition by oxidation in lean atmosphere leads to the recovery of the activity. In addition, water vapor that is present during the rich regeneration exhibited a beneficial effect on the regeneration with higher catalytic activity after regeneration.

For details: Understanding sulfur poisoning of bimetallic Pd-Pt methane oxidation catalysts and their regeneration

Patrick Lott ^a, Mario Eck ^a, Dmitry E. Doronkin ^a,b, Anna Zimina ^b, Steffen Tischer ^b, Radian Popescu ^c, Stéphanie Belin ^d, Valérie Briois ^d, Maria Casapu ^a, Jan-Dierk Grunwaldt ^a,b, Olaf Deutschmann ^a,b

a. Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Engesserstr. 20, 76131, Karlsruhe, Germany

b. Institute of Catalysis Research and Technology (IKFT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344, Eggenstein-Leopoldshafen, Germany

c. Laboratory for Electron Microscopy (LEM), Karlsruhe Institute of Technology (KIT), Engesserstr. 7, 76131, Karlsruhe, Germany

d. Synchrotron SOLEIL, L’Orme des Merisiers - St. Aubin, BP 48, 91192, Gif-sur-Yvette Cedex, France

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Applied Catalysis B: Environmental Journal
https://doi.org/10.1016/j.apcatb.2020.119244
© 2020 Elsevier B.V. All rights reserved. 

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