Charge transfer and charge trapping in zeolites and similar media

Liu, X.; Mao, Yun; Ruetten, S. A.; Thomas, J. K.

doi:10.1016/0927-0248(94)00226-6

Cited by 18 publications

(8 citation statements)

References 65 publications

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“…The decay kinetics of the anthracene radical cation in the presence of electron donors are again complex and do not conform to a single exponential model. Two models which have been shown to successfully describe kinetics in heterogeneous media − ,,,,,,,− have been applied to this data. These are a dispersive kinetic model 28 assuming a distribution of rate constants for the observed reaction, and a model assuming a bimolecular reaction taking place on a fractal dimensional surface which has been applied successfully to triplet−triplet annihilation reactions. − …”

Section: Resultsmentioning

confidence: 99%

Electron Transfer Reactions of Anthracene Adsorbed on Silica Gel

1997

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The production and decay of the anthracene radical cation on silica gel has been studied using nanosecond time-resolved diffuse reflectance laser flash photolysis. The production of the radical cation has been shown to be via a multiphoton process both by a laser dose study and by millisecond flashlamp experiments. The decay kinetics of the radical cation conform well to an analysis based on geminate recombination at loadings of less than 2 µmol g -1 . At higher loadings, deviations from these kinetics are observed caused by bulk electron diffusion competing efficiently with geminate recombination. Addition of electron donors such as triphenylamine, N,N,N′,N′-tetramethyl-1,4-phenylenediamine, N,N-dimethylaniline, and azulene greatly accelerate the rate of radical ion decay via an electron transfer mechanism. Kinetic analysis reveals that the observed decay can be described by either the dispersive kinetic model of Albery et al. or a fractal dimensional rate constant model of the type which has been used to describe triplet-triplet annihilation on surfaces. The bimolecular rate constants vary considerably and do not show a simple dependence on the free energy for electron transfer. This can be explained either on the basis of bulk diffusion of electron donors being slow relative to the electron transfer process, or by the presence of a Marcus "inverted region" at relatively modest negative free energy values.

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Section: Resultsmentioning

confidence: 99%

Electron Transfer Reactions of Anthracene Adsorbed on Silica Gel

1997

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Section: 11 Trapped Electrons and Their Ensuing Reactions4111 Photoio...mentioning

confidence: 99%

Physical Aspects of Radiation-Induced Processes on SiO₂, γ-Al₂O₃, Zeolites, and Clays

Thomas

2005

Chem. Rev.

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“…[40][41][42] In addition to their organized microporous frameworks, an important advantage of zeolites is to offer a high surface area and a cationic exchange capacity that is expected to facilitate the ionization of the adsorbed aromatic molecules and to help creating persistent charge separated states. Moreover, even though the ionization process can be initiated either electrochemically 43 or by photoexcitation 42,[44][45][46][47][48] or radiolysis, 49,50 it can also occur spontaneously if the ionization potential of the molecule is sufficiently low and if the energy of polarization in the zeolite channel is high enough. 40 As a whole, stabilization of the separated charge states in the zeolite can thus be considered as an intrinsic property of the inner charged surface of the zeolite micropores space.…”

Section: Introductionmentioning

confidence: 99%

Electron transfers in a TiO₂-containing MOR zeolite: synthesis of the nanoassemblies and application using a probe chromophore molecule

Legrand

Moissette

Hureau

et al. 2014

Phys. Chem. Chem. Phys.

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New assemblies constituted by a microporous matrix of mordenite (MOR) zeolite on which TiO2 nanoclusters are deposited were synthesized using ionic oxalate complexes and TiCl3 titanium precursors. The samples were used to investigate the transfer of electrons produced by spontaneous or photo-induced ionization of a guest molecule (t-stilbene, t-St) occluded in the porous volume towards the conduction band of a conductive material placed nearby, in the pores or at least close to their entrance. The reaction mechanisms were compared in these Ti-rich solids and in a Ti-free mordenite sample. The characterization by XRD, N2 physisorption, TEM, XPS and DRIFT spectroscopy of the supramolecular TiO2/MOR systems before t-St adsorption showed the preservation of the crystalline structure after Ti addition and thermal activation treatments. They also revealed that titanium is mainly located at the external surface of the zeolite grains, in the form of highly dispersed and/or aggregated anatase. After incorporation of the guest molecule in the new assemblies, diffuse reflectance UV-visible and EPR spectroscopies indicate that the electron transfer processes are similar with and without TiO2 but strongly stabilized t-St˙(+) radicals are detected in the TiO2-MOR samples whereas such species were never detected earlier in TiO2-free mordenite using these techniques. The stabilization process is found to be more efficient in the sample prepared with TiCl3 as the precursor than with titanium oxalates. It is proposed that the proximity of TiO2 with the formed t-St˙(+) radicals provokes the stabilization of the radical through capture of the ejected electron by the semi-conductor and that confinement effects can also play a role.

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Charge transfer and charge trapping in zeolites and similar media

Cited by 18 publications

References 65 publications

Electron Transfer Reactions of Anthracene Adsorbed on Silica Gel

Electron Transfer Reactions of Anthracene Adsorbed on Silica Gel

Physical Aspects of Radiation-Induced Processes on SiO₂, γ-Al₂O₃, Zeolites, and Clays

Electron transfers in a TiO₂-containing MOR zeolite: synthesis of the nanoassemblies and application using a probe chromophore molecule

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Charge transfer and charge trapping in zeolites and similar media

Cited by 18 publications

References 65 publications

Electron Transfer Reactions of Anthracene Adsorbed on Silica Gel

Electron Transfer Reactions of Anthracene Adsorbed on Silica Gel

Physical Aspects of Radiation-Induced Processes on SiO2, γ-Al2O3, Zeolites, and Clays

Electron transfers in a TiO2-containing MOR zeolite: synthesis of the nanoassemblies and application using a probe chromophore molecule

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Product

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Physical Aspects of Radiation-Induced Processes on SiO₂, γ-Al₂O₃, Zeolites, and Clays

Electron transfers in a TiO₂-containing MOR zeolite: synthesis of the nanoassemblies and application using a probe chromophore molecule