Abstract
The interaction of water molecules with the surface of hybrid silica-based mesoporous materials is studied by 29Si, 1H and 13C solid-state NMR and IR spectroscopy, with the support of ab initio calculations. The surface of aminopropyl-grafted mesoporous silica nanoparticles is studied in the dehydrated state and upon interaction with controlled doses of water vapour. Former investigations described the interactions between aminopropyl and residual SiOH groups; the present study shows the presence of hydrogen-bonded species (SiOH to NH2) and weakly interacting “free” aminopropyl chains with restricted mobility, together with a small amount of protonated NH3 + groups. The concentration of the last-named species increased upon interaction with water, and this indicates reversible and fast proton exchange from water molecules to a fraction of the amino groups. Herein, this is discussed and explained for the first time, by a combination of experimental and theoretical approaches.
Lingua originale | Inglese |
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pagine (da-a) | 839-849 |
Numero di pagine | 11 |
Rivista | ChemPhysChem |
Volume | 18 |
Numero di pubblicazione | 7 |
DOI | |
Stato di pubblicazione | Pubblicato - 5 apr 2017 |