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Quantitative Distinction between Noble Metals Located in Mesopores from Those on the External Surface.
- Source :
-
Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2021 Dec 06; Vol. 27 (68), pp. 17012-17023. Date of Electronic Publication: 2021 Aug 05. - Publication Year :
- 2021
-
Abstract
- We compare three methods for quantitatively distinguishing the location of noble metal (NM) particles in mesopores from those found on the external support surface. MCM-41 and SBA-15 with NM located in mesopores or on the external surface were prepared and characterized by TEM. <superscript>31</superscript> P MAS NMR spectroscopy was used to quantify arylphosphines in complexes with NM. Phosphine/NM ratios drop from 2.0 to 0.2 when increasing the probe diameter from 1.08 to 1.54 nm. The reaction between NM and triphenylphosphine (TPP) within 3.0 nm MCM-41 pores takes due to confinement effects multiple weeks. In contrast, external NM react with TPP instantly. A promising method is filling the pores by using the pore volume impregnation technique with tetraethylorthosilicate (TEOS). TPP loading revealed that 66 % of NMs are located on the external surface of MCM-41. The pore filling method can be used in association with any probe molecule, also for the quantification of acid sites.<br /> (© 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)
Details
- Language :
- English
- ISSN :
- 1521-3765
- Volume :
- 27
- Issue :
- 68
- Database :
- MEDLINE
- Journal :
- Chemistry (Weinheim an der Bergstrasse, Germany)
- Publication Type :
- Academic Journal
- Accession number :
- 34251056
- Full Text :
- https://doi.org/10.1002/chem.202102076