Electrochemically Activated Glassy Carbons as potential Supercapacitors and substrates for fixed mediators

Abstract

AbstractGlassy carbon electrodes were prepared in various electrolytes by cyclic voltammetry and constant potential methods under various conditions to explore the factors affecting the response of GC after the electrochemical pretreatment (ECP), including the high pseudo‐capacitance, the great ability to absorb and strongly hold redox species and the facilitation of kinetics of electron transfer. Deepening the oxidation via increasing the oxidation potential and the oxidation time or the number of cycles and the final potential in cyclic voltammetry were found to increase the amount of redox species loaded onto GC and the pseudocapacitance due to formation of thicker carbon oxide layer. The increase in the rate of electron transfer reactions on deepening the oxidation is, however, attributed to the generation of more cleaner surface and more reactive sites. The order of increasing the efficiency of ECP; NaOH>KCl>HCl>NaClO4(MeCN), signifies the role of water and pH on the formation and thickness of the oxide layer formed after ECP. The results support the predominance of the faradaic origin of the pseudo‐capacitance of GC after ECP.