Characterization of adsorbed water in MIL-53(Al) by FTIR spectroscopy and ab-initio calculations.
J Chem Phys
; 142(12): 124702, 2015 Mar 28.
Article
em En
| MEDLINE
| ID: mdl-25833598
ABSTRACT
Here, we report ab-initio calculations developed with a twofold purpose:
understand how adsorbed water molecules alter the infrared spectrum of the metal-organic framework MIL-53(Al) and to investigate which are the associated physico-chemical processes. The analyzed structures are the two anhydrous narrow (npâ) and large (lpâ) pore forms and the hydrated narrow pore form (np-H2O) of the MIL-53(Al). For these structures, we determined their corresponding infrared spectra (FTIR) and we identified the vibrational modes associated to the dominant spectral lines. We show that wagging and scissoring modes of CO2 give flexibility to the structure for facilitating the lpâ- npâ transition. In our studies, this transition is identified by eight vibrational modes including the δCH(18a) vibrational mode currently used to identify the mentioned transition. We report an exhaustive band identification of the infrared spectra associated to the analyzed structures. Moreover, the FTIR for the np-H2O structure allowed us to identify four types of water molecules linked to the host structure by one to three hydrogen bonds.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Chem Phys
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
França