Proceedings of the 1986 International Congress on Renewable Energy Sources. Photoreduction of water sensitised by xanthene dyes. International Congress on Renewable Energy Sources [18-23 Mayo 1986, Madrid].

Consejo Superior de Investigaciones Científicas.
Mills, A. Lawrence, C.

1987

CIENA
1113
v. 2

84-00-6674-X

A series of xanthene dyes (Eosin, Erythosin, Fluorescein, Rose Bengal and Rhodamine 6G) were used to sensitise the photoreduction of water in aqueous ethanol solution (5. ABSTRACT. v/v; pH 4.4) via both a reductive and a oxidative quenching mechanism, using EDTA and methyl viologen, respectively, as quenchers of their triplet states. In the presence of EDTA (which acts as both triplet quencher and sacrifical electron donor) the photoreduction of water sensitised by all the xanthenes was inefficient for a number of reasons including low triplet quenching rate constants and a rapid disproportion reaction involving the protonated semi-reduce dye radicals. In the presence of methyl viologen and EDTA the photoreduction of water sensitised by the xanthene dyes was still inefficient due to: low cage escape yields (usually < 0.2) following the primary electron-transfer step, a rapid back reaction (k >= 1 x 10(Ms -1) and , with the exception of Rhodamine 6G, the formation of xanthenes appeared able to photosensitise, albeit inefficiently, the photoreduction of able to photosensitise, albeit inefficiently, the photoreduction of methyl vilogen in the presence of EDTA, without exhibiting problems of dye fade. INTRODUCTION. EXPERIMETAL. Materials. Methods. RESULTS AND DISCUSSION. Photoreduction of water via a reductive quenching mechanism. Photoreduction of water via an oxidative quenching mechanism. ACKNOWLEDGEMENTS. REFERENCES.

Presenta tbls. y gráfs.

GENERAL; ENERGIA SOLAR; ENERGIA ELECTRICA; EXPERIMENTOS; REACCIONES FOTOQUIMICAS; CONVERSION DE LA ENERGIA;