Understanding the Basics of Electron Transfer and Cyclic Voltammetry of Potassium Ferricyanide - An Outer Sphere Heterogeneous Electrode Reaction

Understanding and controlling the processes occurring at electrode/electrolyte interface are very important in optimizing energy conversion devices. Cyclic voltammetry is a very sophisticated and accurate electroanalytical method enables us to explore the mechanism of such electrode reactions. In this work, electrochemical experiments using cyclic voltammetry were performed in aqueous KCl solution containing potassium ferricyanide, K3[Fe(CN)6] at a glassy carbon disc working electrode and the mechanism of the reactions is highlighted. The CV measurements shows that the ferricyanide [Fe(CN)6]3− reduction to ferrocyanide [Fe(CN)6]4− and the reverse oxidation process follows an outer sphere electrode reaction mechanism. Voltammetry analysis further indicates that the reaction is reversible and diffusion controlled one electron transfer electrochemical process. The peak currents due to [Fe(CN)6]4− oxidation and the peak current due to [Fe(CN)6]3− reduction increase with increase of concentration and scan rate increase. The diffusion co-efficient was determined by applying Randles-Sevcik equation. The report could be helpful for university students to understand the basics of electron transfer in redox processes and cyclic voltammetry.