The kinetics of the polycrystalline Ag/Ag⁺‐electrode studied by high‐frequency impedance spectroscopy

Abstract

ElectrochemistryThe fast charge-transfer reaction of the polycrystalline Ag/Ag+-electrode was studied using a new technique of high-impedance spectroscopy working in the frequency range between 1 kHz and 5 MHz. The method is characterized by a special electrochemical cell with two working electrodes, a new designed dc-control being completely ac-decoupled, a highly precise impedance measurement technique (ICEP = Impedance Conversion and Error Processing) and the quantitative calculation of the electrodynamic field distribution. The accuracy of the measurements is better than 0.05%. The results obtained in the Ag/Ag+-system are in a quantitative agreement with a theoretical transfer function based on a 2-D inhomogeneous surface model. The exchange current densities were found to be about half an order of magnitude higher than the literature data.

Verification and Analysis of Transference Number Measurements by the Galvanostatic Polarization Method

“…We obtained optimal values of i 0 ϭ 0.38 mA/cm 2 and C dl ϭ 0.19 F/cm 2 . Exchange current densities 36,37 and double-layer capacitances [36][37][38][39] reported in the literature vary widely depending on the experimental conditions such as electrode preparation, concentration of supporting electrolyte, and method used. While our value of i 0 seems reasonable and is within the range of literature values (91 A/cm 2 to 24 A/cm 2 ), our capacitance is extremely high.…”

Electrochemical Behavior of YBa2 CU 3 O 7

“…The impedance spectra showed a depressed capacitive semicircle at high and medium frequencies and an inductive loop at low frequencies. Such impedance diagrams are typical for the mainly charge transfer controlled oxygen evolution reaction, which is an inner sphere redox process, taking place on an inhomogeneous electrode surface (29)(30)(31)(32). Similar impedance spectra were also obtained for the oxygen evolution reaction on platinum and graphite electrodes under comparable conditions.…”

“…The transfer function of the system can be described approximately by Ztotal(S) = Ra + Z(s)[1 + seZ(s)] -1 [2] where Z(s) and C denote the impedance of the phase boundary reaction and the electrode capacitance, respectively. Both, Ztotal(S) and Z(s) depend on the surface inhomogeneity (29)(30)(31)(32).…”

In‐Situ Untersuchung von Korrosionsvorgängen an inhomogenen Werkstoffoberflächen mit Hilfe von EIS

“…I(t) wird beobachtet. In diesem Fall wird die Transferfunktion als elektrische Impedanz, Z(s), bezeichnet: [16,17].…”