Interfacial potential distributions

Shiryaeva IM, Collman JP, Boulatov R, Sunderland CJ. 2003. Nonideal electrochemical behavior of biomimetic iron porphyrins Interfacial potential distribution across multilayer films. Anal Chem 79 494. 

From a survey of the literature in chemically modified electrodes [13], one can identify simple phenomenological models that have been very successful for the analysis of a particular aspect of the experimental data. Such models are, for instance, the Dorman partition model [24, 122], the Laviron [158], Albery [159] and Anson models [127] to account for the nonideal peak width, the Smith and White model for the interfacial potential distribution [129], and so on. Most of these models contain one or more adjustable parameters that give some partial information about the system. For example, the lateral interaction model proposed by Anson [127] provides a value for the lateral interactions between oxidized and reduced sites, but does not explain the origin of the interactions, neither does it predict how they depend on the experimental conditions or the polymer structure. In addition, none of these models provide information on the interfacial structure. 

Constant current chronopotentiometry has been utilized by Honeychurch [156] to study reduction of methylene blue adsorbed at HMDE. The obtained results were interpreted in terms of a two consecutive electron transfers (EE) mechanism and the interfacial potential distribution model. 

The second term in eqn. (110) is the double layer correction to the observed reaction order due to the changes in the interfacial potential distribution with the bulk concentration of the ionic reactant. When 9A02/9 In [O] = 0, eqn. (110) becomes identical to eqn. (89) for concentrations instead of activities. This occurs in the presence of large excess of supporting electrolyte, since the concentration of the reacting ion 02o does not determine the interfacial potential distribution and the true reaction order is obtained in eqn. (110). 

For the evaluation of the non-faradaic component of the response in a more realistic way, different proposals have been made. A useful idea is that corresponding to the interfacial potential distribution proposed in [59] which assumes that the redox center of the molecules can be considered as being distributed homogeneously in a plane, referred to as the plane of electron transfer (PET), located at a finite distance d from the electrode surface. The diffuse capacitance of the solution is modeled by the Gouy-Chapman theory and the dielectric permittivity of the adsorbed layer is considered as constant. Under these conditions, the CV current corresponding to reversible electron transfer reactions can be written as... 

The above approaches to treatments of nonideal surface films rely upon empirical adjustable parameters to produce waves with the shapes of experimental ones. By taking into account the interfacial potential distribution (related to such factors as the dielectric constants of film and solution, the concentrations of electroactive adsorbate and supporting electrolyte, and the film thickness) the shape of the cyclic voltammetric curves can also be modeled without the need for such parameters (39). 

Under separate headings, the nature and origin of other membrane potentials diffusion (concentration) potential adsorption (surface or interfacial) potential, distribution (outer) potential, Galvani (inner) potential, and Gouy (Dorman) potential will be considered. These potentials are... 

The link between arc plasmas and electrochemistry was explored by Vijh [14], who studied 32 metals and compared the electrochemical description of the plasma-metal interface with that of treating the interface as a boundary between two plasmas, one for the metal and the other for the arc. Vijh concluded that the interface could be described as a metal/electrolyte interface with a characteristic interfacial potential distribution which depended on the choice of metal. 

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