Bulletin of the Chemical Society of Japan · 1978 · 35 citations · 17 references
Natural SciencesChemistryMaterials ScienceElectrochemistryInorganic ChemistrySurface ScienceMetal Oxide NanomaterialsPhotochemical KineticsPhotochemistryPhotoelectrochemical MaterialsPhotoelectrochemistryRedox-active MaterialsConduction BandNatural DyesOptical Properties Of Metal Oxide NanomaterialsPhotocatalysis By Metal Oxide NanomaterialsReaction Quantum YieldsUltraviolet IrradiationZinc Oxide Nanostructures
Abstract Quantum yields of from 0.235 to 0.385 have been determined for the reduction of Ag+ by the irradiation of 365 nm light on a ZnO surface in aqueous solutions containing 5×10−5 to 1×10−3 M AgClO4. It is proposed that these results can be interpreted by a reaction scheme based on the assumption that some conduction-band electron produced in the ZnO by the irradiation transfers to the Ag+ adsorbed on the ZnO surface. The surface-energy barrier under the present experimental conditions was discussed with the aid of the electrochemical measurement of the ZnO sinter. The photoreduction of Ag+ is optically sensitized by the addition of xanthene dyes, such as Uranine and Rhodamine B. In this case, it is observed that the photoreduction of Ag+ is accompanied by the photolysis of dye molecules. The apparent quantum yields (the number of reacted molecules/the number of photons absorbed in the suspension) of the dye-sensitized photoreduction of Ag+ and the photolysis of dye molecules are 0.015 and 0.007 for Uranine, and 0.003 and 0.0003 for Rhodamine B, respectively.
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