Single-molecule studies of acidity distributions in mesoporous aluminosilicate thin films
Solid acid catalysts are important for many petrochemical processes. The ensemble methods most often employed to characterize acid site properties in catalyst materials provide limited insights into their heterogeneity. Single-molecule (SM) fluorescence spectroscopic methods provide a valuable route...
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1992. - 31(2015), 20 vom: 26. Mai, Seite 5667-75 |
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| Weitere Verfasser: | , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2015
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| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article |
| Zusammenfassung: | Solid acid catalysts are important for many petrochemical processes. The ensemble methods most often employed to characterize acid site properties in catalyst materials provide limited insights into their heterogeneity. Single-molecule (SM) fluorescence spectroscopic methods provide a valuable route to probing the properties of individual microenvironments. In this work, dual-color SM methods are adopted to study acidity distributions in mesoporous aluminosilicate (Al-Si) films prepared by the sol-gel method. The highly fluorescent pH-sensitive dye C-SNARF-1 was employed as a probe. The ratio of C-SNARF-1 emission in two bands centered at 580 and 640 nm provides an effective means to sense the pH of bulk solutions. In mesoporous thin films, SM emission data provide a measure of the effective pH of the microenvironment in which each molecule resides. SM emission data were obtained from mesoporous Al-Si films as a function of Al2O3 content for films ranging from 0% to 30% alumina. Histograms of the emission ratio reveal a broad distribution of acidity properties, with the film microenvironments becoming more acidic, on average, as the alumina content of the films increases. This work provides new insights into the distribution of Brønsted acidity in solid acids that cannot be obtained by conventional means |
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| Beschreibung: | Date Completed 23.07.2015 Date Revised 26.05.2015 published: Print-Electronic ErratumIn: Langmuir. 2018 Mar 6;34(9):3158. - PMID 29457461 Citation Status PubMed-not-MEDLINE |
| ISSN: | 1520-5827 |
| DOI: | 10.1021/acs.langmuir.5b01628 |