Activation of a carbon electrode with zinc compounds

Abstract

The process of cathodic polarization of a carbon electrode in an aqueous solution of zinc chloride with a concentration of 0.5 mmol/l in the potential range from equilibrium to -1.6 V was studied. It was found that staged reduction of zinc ions occurs in this region. At the initial moment after the completion of polarization, the potential of the carbon electrode was -1.2 V, later it increased to 0.8 V under the condition of stabilization in the electrolyte solution, and up to 1 V when the electrode was exposed to air for 15 minutes after polarization (then it was returned to aqueous electrolyte solution, where the potential increase occurred). To explain the potential shift phenomenon, a reaction scheme was proposed, where one of the stages is the formation of zinc peroxide on the surface of the working electrode. The carbon electrode modified with zinc in the course of further studies showed good reproducibility of electrochemical properties, which are proved by the cyclic current-voltage characteristics of cathodic and anode processes.