Environmental effects on photoinduced electron transfer reactions
Photoinduced electron transfer reactions between an electronically excited photosensitizer molecule and a reversible electron acceptor capable of hydrogen production were studied to determine the possible utility of these reactions in solar energy conversion systems. The influence of charged macromolecules on the forward and back electron-transfer reaction between oppositely charged initial photoproducts, the photosensitizer zinc tetra(4-N-methyl pyridinium) porphyrin (ZnP/sup +4/) and the neutral electron acceptor, propyl viologen sulfonate (PVS/sup 0/), has been investigated using continuous photolysis and flash photolysis techniques. Flash photolysis experiments have been performed to study the effect of anionic polyelectrolyte poly(styrene sulfonate) (PSS) on the photoreaction between ZnP/sup +4/ and PVS/sup 0/. These experiments show that all bimolecular rate constants involving PSS-bound ZnP/sup +4/ are decreased by a factor for 40-100. A kinetic model has been developed that describes the transient absorbance behavior of ZnP/sup +4//PVS/sup 0//colloidal silica photolysis systems in which scavenging of PVS/sup -/ by residual O/sub 2/ occurs. Flash photolysis experiments confirmed that alumina-modified silica particles are significantly more effective than unmodified silica sols in neutral pH media at decreasing the rate of back-reaction between ZnP/sup +4/ and PVS/sup -/. 25 refs., 32 figs., 5 tabs.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6228809
- Report Number(s):
- LBL-20817; ON: DE86006445
- Country of Publication:
- United States
- Language:
- English
Similar Records
Function of SiO/sub 2/ colloids in photoinduces redox reactions. Interfacial effects on the quenching, charge separation, and quantum yields. [Propyl viologen sulfonate]
Photoinduced electron transfer between Zn(TPPS)/sub 3//sup 3 -/ and viologens
Related Subjects
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
AZINES
BIPYRIDINES
CARBOXYLIC ACIDS
CHEMISTRY
COMPLEXES
ELECTRON TRANSFER
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
LASERS
MATERIALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC POLYMERS
ORGANIC SULFUR COMPOUNDS
PETROCHEMICALS
PETROLEUM PRODUCTS
PHOTOCHEMISTRY
PLASTICS
POLYMERS
POLYOLEFINS
POLYSTYRENE
POLYVINYLS
PORPHYRINS
PYRIDINES
SULFONATES
SYNTHETIC MATERIALS
ZINC COMPLEXES