The Effects on the Response of Metal Oxide and Fluorite Single Crystal Electrodes and the Equilibration Process in the Interfacial Region

Abstract

Inner surface potential, one of the most important variables affecting the interfacial equilibrium of metal oxide aqueous systems, obtained by means of single crystal electrode gives valuable information about electrical charging of the metal oxide/aqueous electrolyte solution interfaces. The influence of the potential determining ions and ionic strength on the measured electrode potential as well as time of the equilibration, direction of the titration and the effect of the magnetic stirring enables the critical examination of the processes which take place during the interfacial equilibrium. For that purpose, the selected metal oxides (hematite, ceria, sapphire, and rutile) and fluorite single crystal electrodes were examined.

Quartz/Aqueous Electrolyte Solution Interface: Molecular Dynamic Simulation and Interfacial Potential Measurements

“…A quartz (0001) SCrE was constructed, and the electrode potentials with respect to the reference electrode (Ag|AgCl|3 M KCl) were measured with a Methrom pH meter:…”

“…A quartz (0001) SCrE was constructed, 41 and the electrode potentials with respect to the reference electrode (Ag|AgCl|3 M KCl) were measured with a Methrom pH meter: Cu(s)|conductive paint|single crystal|aqueous electrolyte solution|reference electrode…”

Structure and Surface Complexation at the Calcite(104)–Water Interface

“…Instead, SCrE data was included in the model parameterization. For these data, sufficient equilibration time is allowed and measurements are made during no-flow (without stirring) conditions, and therefore kinetic effects remain negligible, while the solution conditions are sufficiently well defined during data acquisition . Remarkably, the parameters that are solely adjusted to the SCrE potentiometric pH titration, namely, the surface protonation constants K >CaOH and K >CO3H , coincide with MUSIC estimates based on the interface structure as depicted in Figure within the accuracy of the structure determination.…”

“…Differences compared to previous Basic-Stern models mainly result from disregarding streaming potential data in the parameterization. The decision to omit these data was due to findings that the flow of non-equilibrium solutions over surfaces affects the surface structure and potential in a complex way. − Since these studies indicate that measurements are influenced by kinetic processes during the flow of non-equilibrium solutions over the surface, such data are not suitable for use in the parameterization of equilibrium models. Instead, SCrE data was included in the model parameterization.…”