Voltammetry coupled with impedance spectroscopy
- PDF / 619,864 Bytes
- 3 Pages / 595.276 x 790.866 pts Page_size
- 76 Downloads / 221 Views
FEATURE ARTICLE
Voltammetry coupled with impedance spectroscopy Tamás Pajkossy 1 Received: 29 May 2020 / Revised: 29 May 2020 / Accepted: 31 May 2020 # The Author(s) 2020
Abstract Dynamic EIS (dEIS) is the joint use of cyclic voltammetry and electrochemical impedance spectroscopy. A method is planned for data evaluation which involves transformations yielding potential program invariant forms of certain characteristic functions. This way of calculation is illustrated by the analysis of two archetypes of electrochemical kinetics. A future task is to develop the related theories and to perform demonstration experiments aimed at establishing dEIS as a robust, general-purpose technique for characterizing electrochemical systems.
Introduction There are two extremes of doing research. One is the work of pioneers—breaking the ground, finding the tools, setting the rules, and showing the directions for the followers. The other is the job of the consolidators: re-doing experiments to confirm (or disprove) the existence of phenomena and/or to provide reliable data, testing or falsifying parts of theories, and reformulating concepts to make the theories concise, that is, to make disciplines well-established. Pioneering is unpredictable, consolidation is a never-ending task. The need for consolidation comes not only from new phenomena and materials but also from technical advancement. This is so also when classical electrochemical methods are considered. These methods, as summarized in a widely used, excellent textbook [1], obtained their mature forms before the era of digital data acquisition—in the age of flatbed recorders. At that time, evaluation of the charts was done by comparing coordinates of characteristic points (e.g., peak location and height) with the related equations. Nowadays, data acquisition methods and computational facilities allow us to include all (or at least many) data points into the analysis instead of a few characteristic points only and to perform complex analyses utilizing the information carried by the entire measured curve.
* Tamás Pajkossy [email protected] 1
Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2, Budapest H-1117, Hungary
Accordingly, the theory on electrochemical kinetics—the subject of which are charge transfer processes affected also by adsorption and transport from/to the interface—should be reshaped, enabling one to extract as much information as possible from measured data. This is, certainly, a task to deal with also in the future. One possible way is outlined here.
The current state A couple of classical, basic electrochemical measurement techniques exist based on measurement of potential E, and current j, as a function of time t (or frequency ω). Some of them, like cyclic voltammetry, CV, are performed in a broad potential range, while others—collectively called electrochemical impedance (or immittance) spectroscopy, EIS— usually in a narrow one. The two methods, CV and EIS, are typically used for dif
Data Loading...
