Wojciech Piasecki

On the Nature of the Energetic Surface Heterogeneity in Ion Adsorption at an Electrolyte/Oxide Interface. Theoretical Studies of the Correlations between Binding-to-Surface Energies of Various Surface Complexes

When a metal oxide is brought into contact with an electrolyte, the outermost surface oxygens adsorb one or two protons, a cation or an aggregate composed of two protons and an anion. In this way, various surface complexes are formed. The actual surfaces are, as a rule, geometrically distorted. This causes a variation of the binding-to-surface energy from one surface oxygen to another for each of these complexes. This energetic heterogeneity of the actual oxide surfaces strongly affects the adsorption of ions within the electrical double layer formed at the oxide/electrolyte interface. The way in which the surface heterogeneity affects the adsorption of ions depends on the correlations between the binding-to-surface energies of the various surface complexes. To date, two extreme models have been considered by us; one assuming the existence of very high correlations, and the other one assuming a total lack of correlation between binding-to-surface energies in going from one surface oxygen to another. This paper presents a theoretical study of ion adsorption based on the assumption of a partial correlation between the binding-to-surface energies.

Calorimetric Effects of Simple Ion Adsorption at the Oxide-Electrolyte Interfaces: Seeking for a Simple Interpretation of the Data Obtained by Titration Calorimetry

The theoretical description of the enthalpic effects accompanying ion adsorption at the oxide-electrolyte interface, developed recently by Rudzinski and co-workers, is used here to analyze the Kallays experimental procedure of determining nonconfigurational heats of proton adsorption in a simple experiment involving use of titration calorimetry. That theoretical analysis, based on considering a certain real adsorption system, leads to important recommendation at which conditions the Kallays titration experiment yields the most reliable figures describing the heats of proton adsorption.

Estimation of enthalpic effects of ion adsorption at oxide/electrolyte interfaces from temperature dependence of adsorption data ☆

It is shown, that some simple relations used commonly to elucidate the enthalpic effects of gas adsorption on solid surfaces from the temperature dependence of adsorption data cannot be applied in the case of ion adsorption at the oxide/electrolyte interfaces.