Unified Model for Transient Faradaic Impedance Spectroscopy: Theory and Prediction
| Autor: | Su-Moon Park, Qiu-An Huang |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Admittance
Chemistry Faradaic impedance Analytical chemistry Overpotential Impedance parameters Surfaces Coatings and Films Electronic Optical and Magnetic Materials Dielectric spectroscopy Solution of Schrödinger equation for a step potential General Energy Physical and Theoretical Chemistry Polarization (electrochemistry) Electrical impedance |
| Zdroj: | The Journal of Physical Chemistry C. 116:16939-16950 |
| ISSN: | 1932-7455 1932-7447 |
| Popis: | We describe a unified model for transient faradaic impedance spectroscopy developed by obtaining a rigorous expression for the current for a potential step to an electrochemical system containing an oxidant and/or a reductant with no assumptions on the reversibility for redox reactions. Effects of electrode reaction kinetic and other parameters such as the exchange rate constant (k 0 ), potential step period (tp), diffusion coefficient (D), transfer coefficient (α), the number of electrons transferred (n), and overpotential (η) on observed impedance parameters have been evaluated using the model. We obtained both polarization resistances (Rp's) and Warburg impedances (Zw's) to characterize the nature of the charge-transfer reaction by showing the evolution trend in terms of their admittances employing kinetic parameters such as η, k 0 , tp, a, n, and D. The peak shift and the half-peak width of Warburg admittance voltammograms were also studied as a function of k 0 .W efinally discuss ranges of step periods, which allow meaningful transient impedance measurements to monitor faradaic processes in real-time by staircase cyclic voltammetric-Fourier transform electrochemical impedance spectroscopy (SCV-FTEIS) experiments, for a given step height. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|