Cadmium Sulfide Photocatalyzed Hydrogen Production from Aqueous Solutions of Sulfite

Abstract

Hydrogen, sulfate, and dithionate are photocatalitically produced in good yield from aqueous solutions of sulfite by using platinum loaded cadmium sulfide powder as reported previously. The reaction rate has been greatly enhanced by the heat treatment of the catalyst, the refined method of platinum loading, the choice of pH of the solution, and temperature. Further details of the experimental conditins of the photocatalytic reactions have been pursued, and reported in this paper. The photocatsalyst’s properties have been discussed on the basis of photoelectrochemical studies of cadmium sulfide electrodes (either single crystal or sinter) and the platinum electrode. These results have led to a further understanding of the reactivity of sulfite ion on cadmium sulfide, the stability of the photocatalyst, temperature dependence of the phototocatalytic reaction, etc. The current-voltage characteristics of CdS-Pt diodes have also been measured to deepen the understanding ot the properties of the electrical contact at the CdS-Pt interface. The barrier hight at the CdS-Pt interface has been discussed for several cases, and the temperature effect has been explained thereof.