Kinetic analysis of electrosorption using fast Fourier transform electrochemical impedance spectroscopy: underpotential deposition of Bi 3+ in the presence of coadsorbing ClO 4− on gold

Abstract

We demonstrate a relatively simple method for studying various kinetic aspects of metal electrodeposition in the presence of coadsorbing anions on an electrode surface. This method combines cyclic voltammetry (CV) with fast Fourier transform electrochemical impedance spectroscopy (FFT-EIS), where both steady state and transient behaviors of the interface are probed simultaneously. As a model surface reaction, we use electrodeposition of Bi 3+ in the presence of ClO 4 − adsorption from an aqueous solution onto a gold electrode. The voltage range for underpotential deposition (UPD) of Bi 3+ is determined with potential step (PS) experiments. The voltage dependent UPD coverage of Bi on Au is determined by analyzing the CV data. The relevant kinetic parameters of both Bi 3+ and ClO 4 − deposition reactions under the conditions of CV are measured with FFT-EIS, and analyzed using a complex nonlinear least square method. The differences and similarities between the electrosorption characteristics of Bi 3+ and ClO 4 − on Au are discussed in terms of these kinetic parameters.