Studying the kinetics of electrode reactions on copper, silver and gold in acid thiourea-citrate electrolytes

Abstract

The kinetics of electrode reactions that take place on copper, silver and gold electrode in acid thiourea-citrate electrolytes has been studied. It is established that the anodic dissolution of metals is accompanied by the formation of stable thiourea metal complexes of a cation-type complex. The citric acid provides the acidic pH-value of the solutions and contributes to the active dissolution of anodes. The ionization rate is limited by the diffusion of charged particles into the electrolyte volume. The cathode reduction of metals obeys the mechanisms of mixed kinetics that includes the diffusion and the preceding chemical complexes dissociation reaction. The charge of the complex ions of copper, silver and gold is +1. Therefore, their dissolution at the anode and reduction at the cathode occurs with the maximum possible electrochemical equivalent.