Properties and applications of electron-transfer photoelectrochemical cells

摘要: A new method known as the photoelectrochemical cell technique is described for the photocatalysis of chemical reactions. Visible irradiation of a half-cell containing sensitizer and quencher leads to electron-transfer quenching of the sensitizer excited state. Addition of a sacrificial reagent, which reacts irreversibly with either, but not both, of the photogenerated redox products to reconvert one to its pre-irradiation oxidation state, stores a fraction of the light energy as the chemical potential of the remaining redox product. Reaction at an electrode returns this product to its pre-irradiation oxidation state and completes the catalytic cycle. Redox equivalents transferred through the external circuit oxidize or reduce an appropriate substrate in a second half-cell. The result is the photocatalysis of the reaction between the sacrificial reagent and substrate.