Thermodynamic and kinetic examination of the glassy carbon electrode in neutral aqueous electrolytes

Abstract

Herein we report on the charge storage behaviour of a non-porous planar glassy carbon electrode (GCE) in an aqueous electrolyte of 0.5 M Na2SO4 at temperatures in the range 25 °C to 50 °C. Preliminary cyclic voltammetry (CV) data indicate a decrease in electrode performance at increasing temperatures, and this was supported by detailed analysis of step potential electrochemical spectroscopy (SPECS) data. Kinetic analysis of the deconvoluted SPECS data using the Arrhenius equation has indicated that diffusional charge storage is not thermally activated, instead being possibly influenced by thermal scattering of electrolyte ions. Entropimetric analysis of the SPECS data has generated entropy and enthalpy data for charge storage in this system. These results are discussed in terms of charge storage at this interface. • Entropy and enthalpy of double layer formation has been examined. • The electrified interface extends a significant distance into the electrolyte. • The implications on double layer formation have been discussed.