Semi-differential analysis of irreversible voltammetric peaks

M Grdeń

doi:10.1007/s10008-016-3461-7

Abstract

Voltammetric peaks obtained by simulation of electrochemical reactions under conditions of linear semi-infinite diffusion with an irreversible electron transfer process are analysed using a semi-differentiation procedure. Obtained semi-derivative peaks, separated or overlapped, are fitted with appropriate mathematical functions. The functions used for data fitting include a function describing symmetrical peaks, proposed by several authors for fitting irreversible semi-derivative peaks, and two alternative functions that express asymmetric shape of the irreversible semi-derivative signals. When applied to the overlapped irreversible semi-derivative peaks, the latter two functions allow calculating certain electrochemical parameters with a better accuracy as compared with the function derived for the symmetrical peaks.

Highlights

Voltammetric curves simulated for processes under conditions of semi-infinite linear diffusion and irreversible charge transfer with both reduced and oxidised species dissolved in the electrolyte were analysed by means of semi-differentiation
Semi-differentiation of strongly overlapped voltammetric signals leads to formation of overlapped semi-derivative peaks whose further analysis must involve fitting with appropriate mathematical functions
Several authors suggested that asymmetric semiderivative peaks obtained for an irreversible electron transfer can be fitted with a mathematical function of the same type as the one used for completely symmetrical semi-derivative signals

Summary

Introduction

Mathematical methods based on semi-differentiation and semi-integration offer an interesting alternative to classical analysis of voltammetric curves [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20] Various electrochemical processes, such as redox reactions with reduced and oxidised species present in the same phase [6, 14, 21,22,23,24,25,26,27,28,29,30,31,32,33,34,35], adsorption on surfaces of electrodes [36,37,38], electrodeposition [39,40,41,42,43,44,45,46,47,48] or electrodissolution [49,50,51] were analysed by means of semi-differentiation or semi-integration.

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Results

Conclusion