Determination of Electronic Recombination Free Energy in Zeolites: Effects of the Charge Balancing Cation and Confinement

Matthieu Hureau; Alain Moissette; Jérémy Gaillard

doi:10.1002/cphc.202000250

Determination of Electronic Recombination Free Energy in Zeolites: Effects of the Charge Balancing Cation and Confinement

Chemphyschem. 2020 Jun 16;21(12):1280-1288. doi: 10.1002/cphc.202000250. Epub 2020 May 27.

Authors

Matthieu Hureau¹, Alain Moissette¹, Jérémy Gaillard¹

Affiliation

¹ LASIRE, Bât. C5 Faculté des Sciences et Technologies, Université de Lille, 59655, Villeneuve d'Ascq cedex, France.

PMID: 32343864
DOI: 10.1002/cphc.202000250

Abstract

The adsorption of DPH in M_6.6 ZSM-5 (M=Na⁺ , K⁺ , Rb⁺ , Cs⁺ ), RbFER and RbMOR channel zeolites takes place without chemical or structural modification. After photoexcitation of these systems, a radical cation-electron pair is observed and has a sufficiently long lifetime to be studied by diffuse reflectance UV-visible spectroscopy. The study of the recombination of this radical cation-electron pair was carried out at different temperatures and allowed the determination of the activation energy as a function of the nature of the charge-balancing cation but also of the confinement effect. It appears that the activation energy decreases progressively from Na⁺ to Cs⁺ but also when the confinement decreases. To go further, the free enthalpies have been calculated from the Marcus theory demonstrating experimentally that these systems are located in the inverted Marcus region.

Keywords: Marcus theory; activation energy; diphenylhexatriene; photo-induced electron transfer; zeolites.