Effect of defects and framework Sn on the stability and activity of Pt clusters for ethane dehydrogenation in chabazite zeolite
| Author(s) | Srinivas, Sanjana | |
| Author(s) | Vlachos, Dionisios G. | |
| Author(s) | Caratzoulas, Stavros | |
| Date Accessioned | 2024-08-14T16:50:22Z | |
| Date Available | 2024-08-14T16:50:22Z | |
| Publication Date | 2024-08-06 | |
| Description | This article was originally published in Reaction Chemistry and Engineering. The version of record is available at: https://doi.org/10.1039/D4RE00187G. This journal is © The Royal Society of Chemistry 2024. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. http://creativecommons.org/licenses/by-nc/3.0/ | |
| Abstract | With increasing interest in new catalytic materials based on atomically dispersed transition metals on various supports (e.g., zeolites or oxides), it is necessary to have an atomic level understanding of the factors that determine their structural and electronic properties as well as catalytic activity. Encapsulated Pt atoms and sub-nanometer Pt clusters in Sn-substituted zeolitic frameworks have demonstrated extended catalytic stability and remarkable selectivity for alkane dehydrogenation to alkenes. Despite efforts to characterize these materials, the bonding environment of the dispersed atoms in the presence of framework Sn or of defect silanols is uncertain. We have employed ab initio molecular dynamics simulations and electronic structure calculations to identify and characterize electronically stable Pt active site motifs in chabazite (CHA) and Sn-CHA at low Pt loadings. The activity of several active site motifs was assessed by microkinetic simulations. We demonstrate that framework Sn and silanol defects can promote the dispersion of Pt species. Unexpectedly, we find that in the presence of silanol nests, the dispersed Pt species statistically prefer to coordinate with the silanols and not with the framework Sn. We show that Pt and Sn are bonded via a 3-center-4-electron bond (O:–Sn–:Pt), affirm the absence of Pt–O–Sn bonding, and thus resolve the ambiguity related to the coordination of Pt to framework Sn. We predict that the O:–Sn–:Pt and Sn–O–Pt–Pt–Si bonding motifs in Sn-CHA are stable and active for ethane dehydrogenation. We relate our findings and conclusions to recent experimental characterization of Pt in Sn-BEA zeolite, point out the close alignment in several aspects and suggest that the effect of framework Sn on the dispersion of low nuclearity Pt species and on the formation of stable and efficient active sites should be largely independent of the framework itself. | |
| Sponsor | This work was supported by the US Department of Energy (DOE), award number DE-SC0024085. The computations were partially supported by Information Technologies (IT) resources at the University of Delaware, specifically the high-performance computing resources. The research was supported in part by the University of Delaware's high-performance computing resources and Information Technologies (IT) resources. The authors thank Dr. Jeff Frey and Alfred Worrad for helping with software installation on the high-performance computing cluster. The authors also thank Prof. Raul Lobo, Roshaan Surendhran, Dr. Tso-Hsuan Chen and Dr. Pavel Kots for several helpful discussions. | |
| Citation | Srinivas, Sanjana, Dionisios G. Vlachos, and Stavros Caratzoulas. “Effect of Defects and Framework Sn on the Stability and Activity of Pt Clusters for Ethane Dehydrogenation in Chabazite Zeolite.” Reaction Chemistry & Engineering, 2024, 10.1039.D4RE00187G. https://doi.org/10.1039/D4RE00187G. | |
| ISSN | 2058-9883 | |
| URL | https://udspace.udel.edu/handle/19716/34698 | |
| Language | en_US | |
| Publisher | Reaction Chemistry and Engineering | |
| dc.rights | Attribution-NonCommercial 3.0 Unported Licence | en |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc/3.0/ | |
| Title | Effect of defects and framework Sn on the stability and activity of Pt clusters for ethane dehydrogenation in chabazite zeolite | |
| Type | Article |
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