Spontaneous charge separation induced by phenothiazine sorption within acidic HnZSM-5

Moissette, Alain; Luchez, F.; Brémard, Claude; Vezin, Herve; Hureau, Matthieu

Document type :

Article dans une revue scientifique

DOI :

10.1039/b900324j

Permalink :

http://hdl.handle.net/20.500.12210/39629

Title :

Spontaneous charge separation induced by phenothiazine sorption within acidic HnZSM-5

Author(s) :

Moissette, Alain [Auteur]

Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516
Luchez, F. [Auteur]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 [LASIRE]
Brémard, Claude [Auteur]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 [LASIRE]
Vezin, Herve [Auteur]

Laboratoire de Chimie Organique et Macromoleculaire [UMR CNRS 8009]
Hureau, Matthieu [Auteur]

Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516

Journal title :

Physical Chemistry Chemical Physics

Abbreviated title :

Phys. Chem. Chem. Phys.

Volume number :

Pages :

4286

Publisher :

Royal Society of Chemistry (RSC)

Publication date :

2009

Article status :

Publié

ISSN :

1463-9084

HAL domain(s) :

Chimie/Chimie théorique et/ou physique

English abstract : [en]

In situ diffuse reflectance UV-visible, Raman scattering and EPR experiments, carried out as a function of time after phenothiazine (PTZ) direct exposure to thermally activated acid HnZSM-5 zeolite without any solvent, ...
Show more >In situ diffuse reflectance UV-visible, Raman scattering and EPR experiments, carried out as a function of time after phenothiazine (PTZ) direct exposure to thermally activated acid HnZSM-5 zeolite without any solvent, provide evidence of phenothiazine sorption and simultaneous spontaneous ionization. For comparison, phenothiazine behavior was investigated within non acidic zeolite and showed that most of the phenothiazine molecules were occluded as intact molecules and that ionization was very weak. The multivariate curve resolution analysis of the diffuse reflectance UV-visible spectra set recorded during the sorption process resolve the absorption spectra and respective concentrations of individual species involved in the sorption course. When PTZ entered through the acidic zeolite channels, PTZ˙+@HnZSM-5˙− radical pair is generated by the polarization energy. Subsequent PTZ2+ formation was fast but only partial. After months, equilibrium including PTZ˙+, PTZ2+ and occluded PTZ was reached within acid HnZSM-5 but depends on the Si/Al ratio: the higher the Al content, the easier the spontaneous ionization. The close match between PTZ and the pore size of zeolites combined with efficient polarizing effect of proton and aluminium electron trapping sites appear to be the most important factors responsible for the stabilization of PTZ˙+ and PTZ2+ and hinder efficiently the charge recombination. No evidence of Brønsted acid sites of HnZSM-5 was found during the sorption of phenothiazine through generation of protonated species.Show less >

Language :

Anglais

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

Université de Lille
CNRS

Collections :

Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516

Submission date :

2021-06-18T08:42:37Z
2021-10-08T12:50:17Z

Version	Link	Modification date
2	20.500.12210/39629*	2021-10-08T12:45:04Z
1	20.500.12210/39629.1	2021-06-18T08:42:37Z

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