ChemInform Abstract: The Effects of pH and Adsorbed Hydrolysed Metal Ions on the Photodissolution of Colloidal Cadmium Sulphide

Abstract

029ChemInform Abstract have been investigated in Ludox stabilized and Ludox-free solution in the presence and absence of Co(II) and Ni(II) ions. The quantum yield for the photodissolution of colloidal CdS decreases with increasing pH. Electrophoresis measurements indicate that this decrease is caused by the formation of Cd2+ hydrolysis products on the surface of the colloid as the pH increases. The deposition of hydrolysed metal ions appears to enhance the recombination of the photo-separated electron-hole pair, leading to a reduction in the photo-degradation of the colloid. Attempts to scavenge the hole using deposited hydrolysed Ni(II) or Co(II) species failed, in contrast with other studies in which Rh2O3 and RuO2 deposited on CdS colloids succeeded in hole scavenging and subsequent O2 production.