TY - JOUR
AU - Huang, Qiu-An
AU - Park, Su-Moon
DA - 2012/08
UR - https://scholarworks.unist.ac.kr/handle/201301/2883
UR - http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84865118877
AB - 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 (t(p)), diffusion coefficient (D), transfer coefficient (alpha), the number of electrons transferred (n), and overpotential (eta) on observed impedance parameters have been evaluated using the model. We obtained both polarization resistances (R-p's) and Warburg impedances (Z(w)'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 eta, k(0), t(p), 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). We finally 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.
LA - ENG
PB - AMER CHEMICAL SOC
KW - Charge-transfer reactions
KW - Electrochemical systems
KW - Electrode reactions
KW - Evolution trend
KW - Exchange rates
KW - Faradaic impedance spectroscopy
KW - Faradaic process
KW - Impedance measurement
KW - Impedance parameters
KW - Number of electrons
KW - Overpotential
KW - Peak shift
KW - Polarization resistances
KW - Potential steps
KW - Reductants
KW - Step height
KW - Transfer coefficient
KW - Unified model
KW - Voltammograms
TI - Unified Model for Transient Faradaic Impedance Spectroscopy: Theory and Prediction
DO - 10.1021/jp306140w
ER -