Quantitative Determination of Ion Migration in a Thin-Layer Electrochemical FT-IR Cell

This paper examines ion migration in thin-layer geometry used in a typical infrared cell designed for probing the electrode/ electrolyte interface. The system used is perchloric acid on a polycrystalline platinum. Previously obtained IR data have been explained qualitatively on the basis of ion migration into the thin-layer electrochemical cell. Here we have measured the extinction coefficient of perchlorate ions in solution and used it to convert IR intensities into a change in concentration of ions in the thin solution layer as a function of electrode potential. The agreement between the IR results and the coulometric data is good. These data are consistent with the lack of specific adsorption of perchlorate anions on a Pt electrode. © 1994, American Chemical Society. All rights reserved.