Comparison between Spontaneous and ...
Type de document :
Article dans une revue scientifique
DOI :
URL permanente :
Titre :
Comparison between Spontaneous and Photoinduced Ionization Mechanisms for p-Quaterphenyl in M-ZSM-5 (M = H+, Na+) Zeolites
Auteur(s) :
Moissette, Alain [Auteur]
Hureau, Matthieu [Auteur]
Carré, Sonia [Auteur]
Vezin, Hervé [Auteur]
Col, Perrine [Auteur]
Hureau, Matthieu [Auteur]
Carré, Sonia [Auteur]
Vezin, Hervé [Auteur]
Col, Perrine [Auteur]
Titre de la revue :
The Journal of Physical Chemistry C
Nom court de la revue :
J. Phys. Chem. C
Numéro :
117
Pagination :
20625-20635
Éditeur :
American Chemical Society (ACS)
Date de publication :
2013-09-30
Mot(s)-clé(s) en anglais :
Charge recombinations
Charge transfer complex
Diffuse reflectance-uv-vis
Electron transfer process
Photo-induced ionization
Reaction conditions
Spectroscopic technique
Uv-vis absorption spectroscopy
charge transfer
Electron spin resonance spectroscopy
Electron transitions
Free radical reactions
Molecules
Positive ions
Reaction kinetics
Ultraviolet spectroscopy
Zeolites
ionization
Charge transfer complex
Diffuse reflectance-uv-vis
Electron transfer process
Photo-induced ionization
Reaction conditions
Spectroscopic technique
Uv-vis absorption spectroscopy
charge transfer
Electron spin resonance spectroscopy
Electron transitions
Free radical reactions
Molecules
Positive ions
Reaction kinetics
Ultraviolet spectroscopy
Zeolites
ionization
Résumé en anglais : [en]
The electron transfers following the initial ionization of a probe molecule (p-quaterphenyl) adsorbed in the channels of M-ZSM-5 (M = H+, Na+) zeolites are investigated using various complementary spectroscopic techniques. ...
Lire la suite >The electron transfers following the initial ionization of a probe molecule (p-quaterphenyl) adsorbed in the channels of M-ZSM-5 (M = H+, Na+) zeolites are investigated using various complementary spectroscopic techniques. Under the same reaction conditions, ionization occurs spontaneously during molecule diffusion in the acid H-ZSM-5 whereas charge separation needs to be photoinduced within the pores of Na-ZSM-5. The electron transfer processes are found to be identical for both the cases in terms of transient species formed before the final charge recombination. The initial ionization leads to the formation of a radical cation which evolves gradually toward an electron/hole pair associated with a charge transfer complex. However, the reaction kinetics depend dramatically on the ionization way. As spontaneous ionization is associated with the sorption process, it is closely correlated with the molecule diffusion and, thus, is very slow due to the bulky size of the molecule. In this case, radical cations and subsequent charge transfer complexes are stabilized for months in high yield and are clearly characterized by diffuse reflectance UV-vis absorption, EPR, and Raman scattering in resonance and in off-resonance conditions. After photoionization, the evolution is followed as a function of time by using time-resolved UV-vis absorption spectroscopy on a large scale of time extending from a few microseconds to several days.Lire moins >
Lire la suite >The electron transfers following the initial ionization of a probe molecule (p-quaterphenyl) adsorbed in the channels of M-ZSM-5 (M = H+, Na+) zeolites are investigated using various complementary spectroscopic techniques. Under the same reaction conditions, ionization occurs spontaneously during molecule diffusion in the acid H-ZSM-5 whereas charge separation needs to be photoinduced within the pores of Na-ZSM-5. The electron transfer processes are found to be identical for both the cases in terms of transient species formed before the final charge recombination. The initial ionization leads to the formation of a radical cation which evolves gradually toward an electron/hole pair associated with a charge transfer complex. However, the reaction kinetics depend dramatically on the ionization way. As spontaneous ionization is associated with the sorption process, it is closely correlated with the molecule diffusion and, thus, is very slow due to the bulky size of the molecule. In this case, radical cations and subsequent charge transfer complexes are stabilized for months in high yield and are clearly characterized by diffuse reflectance UV-vis absorption, EPR, and Raman scattering in resonance and in off-resonance conditions. After photoionization, the evolution is followed as a function of time by using time-resolved UV-vis absorption spectroscopy on a large scale of time extending from a few microseconds to several days.Lire moins >
Audience :
Non spécifiée
Établissement(s) :
Université de Lille
CNRS
CNRS
Collections :
Date de dépôt :
2021-06-17T15:20:08Z
2021-10-01T10:23:55Z
2021-10-01T10:23:55Z