Measurements of the double layer capacitance

All electrochemical processes take place at the electrode/electrolyte interface, i. e. the electrical double layer (Fig. 1). Different models of this layer were stated by Helmholtz, Gouy-Chapman, Stern or Grahame. The structure of the double layer is similar to an electrical condensateur constituted by two charged area separated by a dielectric. The dielectric thickness corresponds to the ionic radius, i. e. 50 nm. In this note, the electrical double layer of iron electrode in acidic condition is investigated. In this purpose, two techniques are used to determine the value of the capacitance: the Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV). VMP3多通道电化学工作站-16通道