Unravelling the Different Reaction Pathways for Low Temperature CO Oxidation on Pt/CeO2 and Pt/Al2O3 by Spatially Resolved Structure-Activity Correlations

Andreas M Gänzler; Maria Casapu; Dmitry E Doronkin; Florian Maurer; Patrick Lott; Pieter Glatzel; Martin Votsmeier; Olaf Deutschmann; Jan-Dierk Grunwaldt

doi:10.1021/acs.jpclett.9b02768

Unravelling the Different Reaction Pathways for Low Temperature CO Oxidation on Pt/CeO₂ and Pt/Al₂O₃ by Spatially Resolved Structure-Activity Correlations

J Phys Chem Lett. 2019 Dec 19;10(24):7698-7705. doi: 10.1021/acs.jpclett.9b02768. Epub 2019 Dec 2.

Authors

Andreas M Gänzler¹, Maria Casapu¹, Dmitry E Doronkin^{1

2}, Florian Maurer¹, Patrick Lott¹, Pieter Glatzel³, Martin Votsmeier⁴, Olaf Deutschmann^{1

2}, Jan-Dierk Grunwaldt^{1

2}

Affiliations

¹ Institute for Chemical Technology and Polymer Chemistry (ITCP) , Karlsruhe Institute of Technology (KIT) , Engesserstraße 20 , 76131 Karlsruhe , Germany.
² Institute of Catalysis Research and Technology (IKFT) , Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1 , 76344 Eggenstein-Leopoldshafen , Germany.
³ European Synchrotron Radiation Facility , 71 avenue des Martyrs CS 40220, 38000 Grenoble Cedex 9, France.
⁴ Umicore AG & Co. KG , Rodenbacher Chaussee 4 , 63457 Hanau , Germany.

PMID: 31730353
DOI: 10.1021/acs.jpclett.9b02768

Abstract

Spatially resolved operando HERFD-XANES (high energy resolution fluorescence detected X-ray absorption near edge structure) complemented by CO concentration gradient profiles along the catalyst bed (SpaciPro) was used to identify the dominant reaction paths for the low and high temperature CO oxidation on Pt/CeO₂ and Pt/Al₂O₃. At low temperatures, features associated with CO adsorption on Pt were found for both catalysts. During the oxidation reaction light-off, the evolution of the spectral and catalytic profile diverged along the catalyst bed. The CO oxidation rate was high on Pt/CeO₂ from the beginning of the catalyst bed with CO being adsorbed on Pt, whereas low CO conversion due to strong CO poisoning was found on Pt/Al₂O₃. This correlation of the CO concentration gradient with unique insight by HERFD-XANES gave direct proof of the crucial contribution of the Pt-CeO₂ perimeter sites overcoming the CO self-inhibition effect at low temperatures.