Characteristics of CdS-Electrochemical Photocell by Using the S₂-/S₂_ Redox System

Abstract

In order to study the characteristics of the electrochemical photocell, CdS/aqueous polysulfide electrolyte/Pt, the anodic polarization characteristics of an illuminated CdS electrode and the cathodic polarization characteristics of a Pt electrode in an aqueous sulfide or polysulfide solu- tion were investigated. Anodic current of the CdS electrode, which was produced by the photoanodic reaction with sulfide or polysulfide ion, was considerably reduced by the absorption of visible light in polysulfide solution. As the reduction of polysulfide ion occurred in preference to the hydrogen evolution on the Pt electrode, this CdS-electrochemical photocell by using an aqueous polysulfide electrolyte was confirmed to be a regenerative photocell. It was also shown that the CdS-electrochemical photocell by using an aqueous sulfide solution instead of an aqueous polysulfide solution gradually became the above-mentioned regenerative photocell as the cell reaction proceeded. It was concluded that the reduction of energy loss, caused by the absorption of visible light in a polysulfide solution, was an important problem for the preparation of an efficient CdS-electrochemical photocell.