Solubility and photocorrosion of small CdS particles

Abstract

In this work small-particle CdS colloids of approximate diameter 250 Å and below 25 Å were prepared and an increase in solubility product from 7.2 × 10-27 for large particles to about 10-15 for small-particle colloids (d < 25 Å) was found. Moreover, the observed change in the cathodic corrosion potential to a more positive value of -0.7 V (for particle sizes below 25 Å) can be explained in terms of the increase in the solubility of the small particles. Cadmium metal formation in the cathodic corrosion process of small-particle colloids was found only in the presence of a sacrificial hole scavenger (triethanolamine), but hydrogen was produced even upon illumination of pure CdS colloid in water (Φ(H2) = 3.84%). © 1988.