Cadmium sulphide colloids

Meyer, M., Wallberg, C., Kurihara, K., and Fendler, J.H., Photosensitized charge separation and hydrogen production in reversed micelle entrapped platinized colloidal cadmium sulphide, /. Chem. Soc., Chem. Commun., 2, 90,1984. 

In recent years there has been interest in using semiconductor dispersions in the form of colloidal particles instead of macroscopic electrodes70. The area/volume ratio is clearly larger, which gives increased yields. Colloidal semiconductors investigated are principally n-Ti02 and cadmium sulphide with adatoms (surface states) of platinum. The particles have to function simultaneously as cathode and anode. Figure 12.24 shows their mode of operation schematically for reduction of A, aided by oxidation of a dye, D. 

J.O. Winter, N. Gomez, S. Gatzert, C.E. Schmidt and B.A. Korgel, Variation of cadmium sulphide nanoparticle size and photoluminescence intensity with altered aqueous synthesis conditions. Colloids and Surfaces A Physicochem. Eng. Aspects, 254 (2005) 147-157. 

Aluminium and magnesium selenides are very similar light brown powders, unstable in air. Zinc and iron (ferrous) selenides are more stable in air, the zinc compound being citron-yellow and the iron compound black and metallic in appearance.8 The latter becomes brown in air owing to oxidation. Ferric selenide is difficult to obtain pure. Cadmium selenide, which is dark brown, is very stable in colour and is used as a pigment. With thallium, selenium is said to form three distinct compounds,9 but analyses of these compounds have led to discordant results. The selenides of aluminium, chromium and uranium cannot be prepared in the wet way. Nickel selenide, unlike the sulphide, shows no tendency to form a colloidal solution. 

---