Mechanisms of electrode process

Chronoamperometry is often used for measuring the diffusion coefficient of electroactive species or the surface area of the working electrode. Analytical applications of chronoamperometry (e.g., in-vivo bioanalysis) rely on pulsing of the potential of the working electrode repetitively at fixed tune intervals. Chronoamperometry can also be applied to the study of mechanisms of electrode processes. Particularly attractive for this task are reversal double-step chronoamperometric experiments (where the second step is used to probe the fate of a species generated in the first step). 

Rotating-Disk Electrode, Study of the kinetics and mechanism of electrode processes under well-defined mass transport conditions is possible through use of methods of the rotating-disk electrode (RDE). The RDE consists of a disk of metal embedded in a cylindrical insulator (e.g., Teflon) holder (see Fig. 6.24). It is rotated about its center. Only the bottom end of the metal disk is exposed to the solution. 

The kinetics and the mechanism of electrode processes are of fundamental importance for electrolytic processes. In melts, there are generally two types of electrode processes ... 

Since the point of bubble evolution represents a more or less indefinite rate of discharge of hydrogen and hydroxyl ions, recent work on overvoltage has been devoted almost exclusively to measurements made at definite c.d. s it is then possible to obtain a more precise comparison of the potentials, in excess of the reversible value, which must be applied to different electrodes in order to obtain the same rate of ionic discharge in each case. The details of the methods of measurement and a discussion of the results will be given after the general problem of the mechanism of electrode processes has been considered. 

M. R. Tarasevich, A. Sadkowski, E. Yeager, in Comprehensive Treatise of Electrochemistry, Kinetics and Mechanisms of Electrode Processes, (Eds. B. E. Conway,... 

The ability of the in situ electrochemical EPR technique to provide information on kinetics and mechanisms of electrode processes is the major reason for its adoption by electrochemists although its major limitation is that it requires... 

In situ electrochemical EPR has been shown to be a useful technique for probing both the kinetics and mechanisms of electrode processes that produce or consume paramagnetic species. A variety of cell designs have been presented, illustrating the scope of this spectroelectrochemical technique. 

Useful information about the adsorption kinetics, mobility of the adsorbed polynucleotide segments, and mechanism of electrode processes can be obtained by measurement of the frequency dependence of the impedance of the electrode double layer (EIS) [31, 88, 207-209]. If the adsorption/desorption process is slow with respect to the period of the a.c. potential used for the impedance measurement, the measured capacitance values decrease with increasing frequency (dispersion of the capacity). The frequency effect is most remarkable around the potentials of adsorption/desorption peaks. With more flexible ss polynucleotides, the frequency effect is larger than with the more rigid ds ones [210]. 

Volume 7 KINETICS AND MECHANISMS OF ELECTRODE PROCESSES Edited by Brian E. Conway, J. O M. Bockris, Ernest Yeager,... 

Our presentation will not include any numerical handling of experimental data, our purpose being only to provide a new set of theoretical tools for the unraveling of the mechanisms of electrode processes which convinced readers will then best be able to use in the interpretation of their own experimental work. 

Krishtalik LI (1983) Kinetics of electrochemical reactions at metal-solutiMi interfaces. In Ctmway B, Bockris J, Yeager E, Khan S, White R (eds) Kinetics and mechanisms of electrode processes, vol 7, Comprehaisive treatise of electrochemistry. Plenum Press, New Yodc... 

Electrochemical surface science has undergone rapid development in recent years due to the adaptation of ultrahigh-vacuum- (UHV-) based experimental techniques such as low-energy electron diftaction (LEED), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and high-resolution electron energy loss spectroscopy (HREELS). These techniques have allowed the establishment of a direct correlation between the composition and structure of the electrode surface and the mechanism of electrode processes. The adaptation of these techniques has buttressed a variety of classical electrochemical techniques that demand theoretical models in order to arrive at a semblance of mechanistic features at the atomic level. 

In addition to utilization of combined UHV and electrochemistry (UHV-EC), the enormous growth witnessed in the past ten years can be attributed to the inclusion of scanning tunneling microscopy (STM) and atomic force microscopy (AFM) in the analytical arsenal. STM-AFM-based data were employed to support or dispute earlier results from purely electrochemic or UHV-EC techniques stimulating scientific discussions ensued. The scientific debate about the mechanism of electrode processes vis-d-vis the structure and composition of the electrochemical interface subsequently spurred theorists to wade in and join the debate. 

Baltrunas, G. (2003) The mechanism of electrode process in the system silver/silver cyanide complexes. Elec-trochim. Acta, 48 (24), 3659—3664. 

Attention in the investigations cited was focused on problems of an applied nature, underlining the influence of the solution composition and electrolysis conditions on the phase and elemental composition of coatings. Atheoretical analysis of kinetics and the mechanism of electrode processes were often omitted. In this connection, we present next the main results of our investigations concerning the kinetics of codeposition of tin and cobalt in the solutions containing citric acid (LHJ [15,16]. 

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