MECHANISM OF THE ELECTROCHEMICAL REACTIONS OF THIOUREA AT POLYCRYSTALLINE SILVER AND COPPER ELECTRODES IN ALKALINE MEDIA.

Thiourea has found widespread use in a variety of biological and industrial applications. The authors discuss the mechanisms of the reactions that occur during the deposition and dissolution steps in the course of cathodic stripping voltammetric (CSV) experiments at silver and copper electrodes. Experimental results show that thiourea undergoes similar decomposition upon anodization at a polycrystalline copper electrode. This decomposition leads to the formation of cuprous sulfide (Cu//2S) and sulfide ions giving a CSV peak at E equals minus 1100 mV. However, in contrast to a silver electrode, no adsorption film was detected at copper. Also, more pronounced irreversibility of the corresponding process C//1 minus A//1 as indicated by a larger peak separation is observed.