Cleavage of Water by Visible-Light Irradiation of Colloidal CdS Solutions; Inhibition of Photocorrosion by RuO2

The conversion of light into chemical fuels in photochemical devices equipped with semiconductor electrodes (e.g. of n-CdS) is associated with a serious problem: “holes” produced in the valence band of the semidonductor upon irradiation migrate to the surface where photocorrosion occurs. In mi-croheterogenous CdS systems this is remedied by a thin layer of RuO2. A CdS sol prepared in the presence of maleic anhydride/styrene copolymer has now been loaded with RuO2 and Pt; these CdS microelectrodes are surprisingly active catalysts for cleavage of H2O and H2S.