| Autor: |
Sambhu Radhakrishnan, Sam Smet, C. Vinod Chandran, Sreeprasanth Pulinthanathu Sree, Karel Duerinckx, Gina Vanbutsele, Johan A. Martens, Eric Breynaert |
| Jazyk: |
angličtina |
| Rok vydání: |
2023 |
| Předmět: |
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| Zdroj: |
Molecules, Vol 28, Iss 18, p 6456 (2023) |
| Druh dokumentu: |
article |
| ISSN: |
1420-3049 |
| DOI: |
10.3390/molecules28186456 |
| Popis: |
Selective catalytic reduction (SCR) of NOx by ammonia is one of the dominant pollution abatement technologies for near-zero NOx emission diesel engines. A crucial step in the reduction of NOx to N2 with Cu zeolite NH3-SCR catalysts is the generation of a multi-electron donating active site, implying the permanent or transient dimerization of Cu ions. Cu atom mobility has been implicated by computational chemistry as a key factor in this process. This report demonstrates how variable temperature 1H NMR reveals the Cu induced generation of sharp 1H resonances associated with a low concentration of sites on the zeolite. The onset temperature of the appearance of these signals was found to strongly correlate with the NH3-SCR activity and was observed for a range of catalysts covering multiple frameworks (CHA, AEI, AFX, ERI, ERI-CHA, ERI-OFF, *BEA), with different Si/Al ratios and different Cu contents. The results point towards universal applicability of variable temperature NMR to predict the activity of a Cu-zeolite SCR catalyst. The unique relationship of a spectroscopic feature with catalytic behavior for zeolites with different structures and chemical compositions is exceptional in heterogeneous catalysis. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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