Nanostructured Pr-Rich CexPr1-xO2-δ Mixed Oxides for Diesel Soot Combustion: Importance of Oxygen Lability
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http://hdl.handle.net/10045/141308
Títol: | Nanostructured Pr-Rich CexPr1-xO2-δ Mixed Oxides for Diesel Soot Combustion: Importance of Oxygen Lability |
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Autors: | Mekki, Imene | Grzybek, Gabriela | Kotarba, Andrzej | Garcia-Garcia, Avelina |
Grups d'investigació o GITE: | Materiales Carbonosos y Medio Ambiente |
Centre, Departament o Servei: | Universidad de Alicante. Departamento de Química Inorgánica | Universidad de Alicante. Instituto Universitario de Materiales |
Paraules clau: | Ceria-praseodymia nanoparticles | Diesel soot combustion | Catalytic activity | Oxygen vacancies |
Data de publicació: | 7-de març-2024 |
Editor: | MDPI |
Citació bibliogràfica: | Nanomaterials. 2024, 14(6): 483. https://doi.org/10.3390/nano14060483 |
Resum: | Soot combustion experiments with 5%O2/He were conducted using model soot, and four distinct compositions of CexPr1-xO2-δ oxides of varying nominal cerium compositions (x = 0, 0.2, 0.3, and 1) were prepared. The catalyst samples were comprehensively characterized using techniques such as XRD, Raman spectroscopy, HR-TEM, N2 adsorption at −196 °C, XPS, O2-TPD, H2-TPR, and work function measurements. The Pr-rich compositions, ranging from Ce0.3Pr0.7O2-δ to PrO2-δ, resulted in a significant increase in the total evolved O2 amounts and enhanced catalyst reducibility. However, a decrease in the textural properties of the catalysts was noted, which was particularly important for the pure praseodymia under the synthesis route conducted. The catalytic activity was investigated under the two following contact modes of mixing between soot and catalyst: loose and tight. The results revealed that the catalytic performance is associated with the surface contact in tight contact mode and with the combination of surface/subsurface/bulk oxygen mobility and the BET surface area in loose contact mode. Notably, the temperatures estimated at 10% and 50% of the conversion (T10 and T50) parameters were achieved at much lower temperatures than the uncatalyzed soot combustion, even under loose contact conditions. Specifically, the 50% conversion was achieved at 511 °C and 538 °C for Ce0.3Pr0.7O2 and Ce0.2Pr0.8O2, respectively. While no direct correlation between catalytic activity and work function was observed, a significant relationship emerges between work function values and the formation of oxygen vacancies, whatever the conditions used for these measurements. On the other hand, the ability to generate a high population of oxygen vacancies at low temperatures, rather than the direct activation of gas-phase O2, influences the catalytic performance of Pr-doped ceria catalysts, highlighting the importance of surface/subsurface oxygen vacancy generation, which was the parameter that showed a better correlation with the catalytic activity, whatever the soot conversion value or the mode of contact considered. |
Patrocinadors: | This research was funded by the financial support of the Spanish Ministry of Science and Innovation/Research Spanish Agency (PID2019-105542RB-I00/AEI/10.13039/501100011033 project), UE-FEDER funding, and Generalitat Valenciana (CIPROM/2021/070 project). I.M. also acknowledges the Algerian Ministry of Higher Education and Scientific Research for the financial support provided through the national grant. |
URI: | http://hdl.handle.net/10045/141308 |
ISSN: | 2079-4991 |
DOI: | 10.3390/nano14060483 |
Idioma: | eng |
Tipus: | info:eu-repo/semantics/article |
Drets: | © 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). |
Revisió científica: | si |
Versió de l'editor: | https://doi.org/10.3390/nano14060483 |
Apareix a la col·lecció: | INV - MCMA - Artículos de Revistas |
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