Broad Considerations Concerning Electrochemical Electrodes in Primarily Fluid Environments

Abstract

This review is variously a presentation, reflection, synthesis and report with reference to more recent developments of an article – in a journal which has ceased publication – entitled “Some Electrode Theorems with Experimental Corroboration, Inclusive of the Ag/AgCl System” Internet Journal of Chemistry, (http://www.ijc.com), Special Issues: Vol. 2 Article 24 (1999). The results from new lemmas relating charge densities and capacitance in a metallic electrode in equilibrium with an ionic solution are used to explain the data and observed effects due to Esin, Markov, Grahame, Lang and Kohn. Size effects that vary the measured e.m.f. of electrodes due to changes in the electronic chemical potential are demonstrated in experiment and theory implying the need for standardization of electrodes with respect to geometry and size. The widely used Stern modification of the Gouy-Chapman theory is shown to be mostly inapplicable for many of the problems where it is employed. Practical consequences of the current development include the possibility of determining the elusive single-ion activity coefficients of solution ions directly from the expression given by a simplified capacitance theorem, the potential of zero charge and the determination of single ion concentrations of active species in the electrode reactions from cell e.m.f. measurements.

Health-Related Electromagnetic Field Assessment in the Proximity of High Voltage Power Equipment

“…The magnetic field must be measured at a height of 1 m from the ground level around the considered equipment at a horizontal distance of 0.3 m from the surface of the equipment, at intervals considered appropriate to find the maximum level point of the magnetic field [15].…”

How Do Liquid-Junction Potentials and Medium Polarity at Electrode Surfaces Affect Electrochemical Analyses for Charge-Transfer Systems?

“…The electrolyte, added to the analyte solutions for ensuring sufficient electrical conductivity, introduces challenges for estimating the polarity of the microenvironment where the electrochemical reduction and oxidation occur. For example, the Gouy–Chapman–Stern (GCS) model offers a means for estimating the increased concentration of ions in the Helmholtz and the diffused layers at the surfaces of polarized electrodes. − The GCS formalism, however, assumes a static dielectric constant, ε, at the electrode surfaces that is identical to ε of the bulk solution, and often approximated to the dielectric constant of the solvent. Conversely, an increase in electrolyte concentration ( C el ) can substantially increase or decrease the dielectric constant of a solution, depending on if the ions have chaotropic or kosmotropic effects on the solvent structure. − Furthermore, the dielectric properties of the double layers at electrode surfaces, where the electrochemical reduction and oxidation occur, differ from the dielectric properties of the bulk electrolyte solution.…”

“…For example, the Gouy–Chapman–Stern (GCS) model offers a means for estimating the increased concentration of ions in the Helmholtz and the diffused layers at the surfaces of polarized electrodes. 7 − 9 The GCS formalism, however, assumes a static dielectric constant, ε, at the electrode surfaces that is identical to ε of the bulk solution, and often approximated to the dielectric constant of the solvent. Conversely, an increase in electrolyte concentration ( C el ) can substantially increase or decrease the dielectric constant of a solution, depending on if the ions have chaotropic or kosmotropic effects on the solvent structure.…”