HOMOGENEOUS AND HETEROGENEOUS PHOTOCATALYTIC CLEAVAGE OF WATER USING SUNLIGHT
This study comprises a search for suitable photo(electro)chemical systems for practical water photoelectrolysis. We have concentrated first on the sensitization towards visible light of the n-type semiconductor SrTiO-3. It is possible to sensitize the wide band gap SrTiO-3 photoanode by two ways: transition metal dye sensitization and transition metal ion doping. The model dye ruthenium tris-(2,2'-bipyridine) and water insoluble surfactant derivatives thereof have been shown to have low efficiency and seemingly insurmountable stability problems. In the doping approach of the titanates the photoelectrolysis may be carried out under alkaline conditions were these materials are more stable. Several concepts where introduced and tested: surface doping of semiconductors for preparation of inhomogeneously doped semiconductors; a charge transfer model for understanding and predicting the effectiveness of various first row transition metal ions M**u+ as a dopant, based on the charge transfer transition M**n+ -> Ti**4+; and charge compensation for introducing high "dopant" levels. n-SrTiO-3 powders mixed with LaCrO-3 were tested for the oxidation of water by a sacrificial system with persulfate ions, using UV light. Another n- or p-type semiconductor silicon carbide SiC, has been investigated. We also studied the monocrystalline and powder properties of a new small band gap semiconductor (p- type zinc phosphide alpha- and beta-ZnP-2).
Bibliographic Reference: EUR 9527 EN (1984) MF, 125 P., BFR 240, BLOW-UP COPY BFR 625, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989123100400 / Last updated on: 1987-01-01
Available languages: en