Spectroelectrochemistry using a moveable electrode

Abstract

A cell for SpectroElectroChemistry Using a Moveable Electrode (SECUME) is described, its electrochemical behavior as a function of the solution thickness is characterized and its utility in spectroscopic applications is demonstrated. The compact, low-volume cell can be used for either aqueous or non-aqueous studies. The cell does obey electrochemical theory for bulk measurements, but not for thin layer conditions. This lack of agreement in the thin layer regime is explained in terms of the non-uniform potential profile inherent in the circular electrochemical geometry and the large size of the electrode. Under thin layer conditions however, rapid redox chemistry and excellent spectroscopy can be accomplished. The spectroscopic characterizations of the cell are presented in the FTIR, Raman and UV/Vis where the advantage of a variable pathlength afforded by the moveable electrode is demonstrated. Other features of the cell include simple fore-optics, interchangeable windows and working electrodes, ease of filling and cleaning, and a palladium-hydrogen reference electrode.