Kinetics of interfacial ion-transfer reactions studied using the indirect laser-induced temperature jump technique: Theory

For fast, interfacial ion-transfer (adsorption/desorption) reactions, I demonstrate the development of a relationship describing the time dependence of the open-circuit potential change (ΔVoc(t)) initiated by the coulostatic temperature perturbation associated with the indirect laser-induced temperature jump (ILIT) technique. The form of this relationship is exactly the same as the one developed for interfacial electron-transfer (ET) reactions of solution-dissolved redox couples. However, the definitions of the parameters associated with this relationship (e.g., the measured rate constant (km,a/d) and the mass-transfer parameter (P75,a/d)) are unique to and are functions of the chemical kinetic and (some of) the thermodynamic properties of the adsorption/desorption reactions. An additional analysis of the time dependence of the ILIT-induced open-circuit potential change (ΔVoc,et(t)) effected by the ET reaction of a reversibly adsorbed redox couple (where only the adsorbed redox species undergo the ET reaction) also results in a relationship that is the same as that developed for solution-dissolved redox couples, but the definitions of km,et and P75,et are, again, different for the reversibly adsorbed redox moieties. The analyses associated with these developments are relevant to possible studies (using ILIT or other coulostatic perturbation techniques) of the adsorption/desorption reactions pertinent to many technologically important electrochemical processes.