Platinum electrodes surface relaxation

Transient measnrements (relaxation measurements) are made before transitory processes have ended, hence the current in the system consists of faradaic and non-faradaic components. Such measurements are made to determine the kinetic parameters of fast electrochemical reactions (by measuring the kinetic currents under conditions when the contribution of concentration polarization still is small) and also to determine the properties of electrode surfaces, in particular the EDL capacitance (by measuring the nonfaradaic current). In 1940, A. N. Frumkin, B. V. Ershler, and P. I. Dolin were the first to use a relaxation method for the study of fast kinetics when they used impedance measurements to study the kinetics of the hydrogen discharge on a platinum electrode. 

The adsorption of anions on metal electrodes has been studied in electrochemistry since the midfifties by many authors. The two main problems with these studies were the cleanliness of the electrolyte and the crystal orientation and topology of the noble-metal surfaces. At the beginning of the twenty-first century, the incorporation of in situ surface sensitive techniques became a reality among the electrochemists. The case of the specific adsorbable anions deserves special attention because their interaction with the surface can induce surface relaxation of the metal. One of the most interesting and important interfaces is the (bi)sulfate/platinum system. 

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