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VOLTAMMETRY | Linear Sweep and Cyclic
188 VOLTAMMETRY / Linear Sweep and Cyclic 14
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−50 −100
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−4 −6 (A)
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Figure 8 (A) First three sweeps of a voltammogram for an EC reaction at a scan rate of 0.2 V s 1. (B) Voltammogram for the same system as in (A) at a scan rate of 50 V s 1.
where en is ethylenediammine. Figure 8A shows a slow scan rate (0.2 V s 1) cyclic voltammogram for an EC reaction: A þ e-B B-C
where the reduced product, B, undergoes a reaction to form C, which is electroinactive. The ratio of anodic peak current to cathodic peak current is less than 1. Figure 8B illustrates the same system while using a sweep rate of 50 V s 1. The smaller timescale of the voltammogram in Figure 8B illustrates the ability of higher sweep rate cyclic voltammetry to outrun the following chemical reaction. See also: Voltammetry: Linear Sweep and Cyclic; Anodic Stripping; Cathodic Stripping; Inorganic Compounds; Organic Compounds.
Further Reading Bard AJ and Faulkner LR (2001) Electrochemical Methods: Principles and Applications, 2nd edn. New York: Wiley. Bond AM (2002) Broadening Electrochemical Horizons: Principles and Illustration of Voltammetric and Related Techniques. Oxford: Oxford University Press. Brett CMA and Brett AMO (1993) Electrochemistry: Principles, Methods and Applications. Oxford: Oxford University Press. Forster RJ, Vos JG, and Keyes TE (2003) Interfacial Supramolecular Assemblies. New York: Wiley. Pletcher D (2002) Instrumental Methods in Electrochemistry. Albion/Horwood. Wang J (2000) Electroanalytical Techniques, 2nd ed. New York: Wiley. Wightman RM and Wipf DO (1989) In: Bard AJ (ed.) Electroanalytical Chemistry, vol. 15. New York: Dekker.
Linear Sweep and Cyclic G Bontempelli and R Toniolo, Universita` degli Studi di Udine, Udine, Italy & 2005, Elsevier Ltd. All Rights Reserved.
Introduction Linear sweep voltammetry (LSV) and cyclic voltammetry (CV) are the most widely used voltammetric techniques for studying redox reactions of both organic and inorganic compounds because they are unmatched in their ability to provide information on the steps involved in electrochemical processes
with only a modest expenditure of time and effort in the acquisition and interpretation of data. These electroanalytical methods require simple and inexpensive instrumentation and provide not only information on the electrochemical quantities typical of a redox process, but also allow investigations of chemical reactions coupled with charge transfer steps. This is because the electrode can be used as a tool for producing reactive species in a small solution layer surrounding its surface and at the same time to monitor chemical reactions involving these species. Moreover, since the relevant responses can be obtained within a few milliseconds after stimulation of the
200
12
150
10
100
8
2
0 0.8
0.6
0.4
0.2 E (V)
0 0.6
0.4
0.2
0 E (V)
−50 −100
−2
−150
−4 −6 (A)
0
i (µA)
4
50 i (µA)
6
− 200 (B)
Figure 8 (A) First three sweeps of a voltammogram for an EC reaction at a scan rate of 0.2 V s 1. (B) Voltammogram for the same system as in (A) at a scan rate of 50 V s 1.
where en is ethylenediammine. Figure 8A shows a slow scan rate (0.2 V s 1) cyclic voltammogram for an EC reaction: A þ e-B B-C
where the reduced product, B, undergoes a reaction to form C, which is electroinactive. The ratio of anodic peak current to cathodic peak current is less than 1. Figure 8B illustrates the same system while using a sweep rate of 50 V s 1. The smaller timescale of the voltammogram in Figure 8B illustrates the ability of higher sweep rate cyclic voltammetry to outrun the following chemical reaction. See also: Voltammetry: Linear Sweep and Cyclic; Anodic Stripping; Cathodic Stripping; Inorganic Compounds; Organic Compounds.
Further Reading Bard AJ and Faulkner LR (2001) Electrochemical Methods: Principles and Applications, 2nd edn. New York: Wiley. Bond AM (2002) Broadening Electrochemical Horizons: Principles and Illustration of Voltammetric and Related Techniques. Oxford: Oxford University Press. Brett CMA and Brett AMO (1993) Electrochemistry: Principles, Methods and Applications. Oxford: Oxford University Press. Forster RJ, Vos JG, and Keyes TE (2003) Interfacial Supramolecular Assemblies. New York: Wiley. Pletcher D (2002) Instrumental Methods in Electrochemistry. Albion/Horwood. Wang J (2000) Electroanalytical Techniques, 2nd ed. New York: Wiley. Wightman RM and Wipf DO (1989) In: Bard AJ (ed.) Electroanalytical Chemistry, vol. 15. New York: Dekker.
Linear Sweep and Cyclic G Bontempelli and R Toniolo, Universita` degli Studi di Udine, Udine, Italy & 2005, Elsevier Ltd. All Rights Reserved.
Introduction Linear sweep voltammetry (LSV) and cyclic voltammetry (CV) are the most widely used voltammetric techniques for studying redox reactions of both organic and inorganic compounds because they are unmatched in their ability to provide information on the steps involved in electrochemical processes
with only a modest expenditure of time and effort in the acquisition and interpretation of data. These electroanalytical methods require simple and inexpensive instrumentation and provide not only information on the electrochemical quantities typical of a redox process, but also allow investigations of chemical reactions coupled with charge transfer steps. This is because the electrode can be used as a tool for producing reactive species in a small solution layer surrounding its surface and at the same time to monitor chemical reactions involving these species. Moreover, since the relevant responses can be obtained within a few milliseconds after stimulation of the