Kinetic Investigation of the Fe²⁺/Fe³⁺ Reaction in Frozen and Liquid HClO₄·5.5H₂O

Abstract

The Fe2+/Fe3+ redox reaction on platinum is investigated in liquid and frozen HC104. 5.5H20 over a temperature range from 130-300 K. The exchange current density follows an Arrhenius law in the liquid and in the solid state. Both the energy of activation and the preexponential factor are higher in the solid state; the exchange current density shows a discontinuous rise as one approaches the freezing point from higher temperatures. In the liquid state, mass transport to the electrode occurs through diffusion of the ions; in the solid state mass transfer is much slower, and is probably due to electron hopping rather than ion transport.

Influence of low temp. and electrical field strength on oxygen evolution (photo)catalysis with n-ruthenium disulfide electrodes

“…Two possibilities exist, at least, to fulfill this condition. The corrosion process of RuS2 semiconducting electrodes follows according to RuS2 + 12H20 -Ru042~+ 2S042" + 24H+ + 20e" (4) and via a surface oxidation reaction which can be represented by RuS2 yr S2_"RuO, + xSO<2' + 8xe"…”

Solid-State Voltammetry — Analytical Prospects

“…Because of the practical requirement of the presence of a supporting electrolyte, such measurements have traditionally been confined to fluid solutions. More recently, electrochemical studies have been extended to electrodes modified with thin, three-dimensional, polymeric films of organic and inorganic materials (exposed to liquid supporting electrolytes) [4][5][6], as well as to the investigations of frozen electrolytes [7] and to solid ionic conductors at elevated temperatures [8]. These fields are not reviewed systematically herein because their general scopes are of secondary interest to our objectives.…”

First Direct In Situ EPR Spectroelectrochemical Evidence of the Superoxide Anion Radical

“…The good signal-to-noise ratio of the OO –• spectra measured in the flat cell as soon as the solution was frozen inspired us to try the direct EPR detection of electrochemically generated OO –• in frozen DMSO. The feasibility of electrochemical reduction or oxidation in the solid state was shown first for some frozen water containing electrolytes, , but there are also few reports on electrochemical investigations in frozen DMSO. , …”