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Insights into the Structural Dynamics of Pt/CeO$_{2}$ Single-Site Catalysts during CO Oxidation

Dolcet, Paolo 1; Maurer, Florian 1; Casapu, Maria 1; Grunwaldt, Jan-Dierk 1,2
1 Institut für Technische Chemie und Polymerchemie (ITCP), Karlsruher Institut für Technologie (KIT)
2 Institut für Katalyseforschung und -technologie (IKFT), Karlsruher Institut für Technologie (KIT)

Abstract:
Despite their high atomic dispersion, single site catalysts with Pt supported on CeO$_{2}$ were found to have a low activity during oxidation reactions. In this study, we report the behavior of Pt/CeO$_{2}$ single site catalyst under more complex gas mixtures, including CO, C$_{3}$H$_{6}$ and CO/C$_{3}$H$_{6}$ oxidation in the absence or presence of water. Our systematic operando high-energy resolution-fluorescence-detected X-ray absorption near-edge structure (HERFD-XANES) spectroscopic study combined with multivariate curve resolution with alternating least squares (MCR-ALS) analysis identified five distinct states in the Pt single site structure during CO oxidation light-off. After desorption of oxygen and autoreduction of Pt$^{4+}$ to Pt$^{2+}$ due to the increase of temperature, CO adsorbs and reduces Pt$^{2+}$ to Pt$^{δ+}$ and assists its migration with final formation of Pt$_{x^Δ+}$ clusters. The derived structure–activity relationships indicate that partial reduction of Pt single sites is not sufficient to initiate the conversion of CO. The reaction proceeds only after the regrouping of several noble metal atoms in small clusters, as these entities are probably able to influence the mobility of the oxygen at the interface with ceria.


Verlagsausgabe §
DOI: 10.5445/IR/1000133308
Veröffentlicht am 26.05.2021
Originalveröffentlichung
DOI: 10.3390/catal11050617
Scopus
Zitationen: 1
Web of Science
Zitationen: 1
Dimensions
Zitationen: 1
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Katalyseforschung und -technologie (IKFT)
Institut für Technische Chemie und Polymerchemie (ITCP)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 05.2021
Sprache Englisch
Identifikator ISSN: 2073-4344
KITopen-ID: 1000133308
HGF-Programm 38.03.04 (POF IV, LK 01) Technical Fuel Assessment
Erschienen in Catalysts
Verlag MDPI
Band 11
Heft 5
Seiten Art.-Nr. 617
Bemerkung zur Veröffentlichung This article belongs to the Special Issue Present Challenges in Catalytic Emission Control for Internal Combustion Engines
Vorab online veröffentlicht am 11.05.2021
Nachgewiesen in Web of Science
Scopus
Dimensions
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