No abstract

This paper is a continuation of studies on the platinized platinuln electrode in acid solutions saturated with hydrogen. The object was to secure information on the behavior of the electrode as current is passed through it. In all cases the solution was saturated with hydrogen. I)ata were obtained under four sets of conditions. (1) The electrode was cathodically polarized, then ilnmediately anodically polarized in a still solution.(2) The procedure was the same as (1) except the solution was stirred by a rapid stream of hydrogen. (3) The electrode was anodically polarized, then followed by cathodic polarization in a still solution. (4) The procednre was the same as (3) except the solution was stirred by a rapid stream of hydrogen. The results all support the proposition sublnitted in previous papers that the electrode phenolnena below, at, and above the so-called reversible value are all the salne; and that the potential of the electrode under any of these conditions is deterlnined by the activity of hydrogen atoms and hydrogen ions at the electrode-solution interface and could be calculated by the regular Nernst equation provided these activities were known. A corollary of the theory is, of course, that hydrogen ions may be discharged at potentials more positive than the so-called reversible value; also that the activity of the hydrogen atoms, and thus the potential, depends largely upoll the material and physical condition of the electrode.

This is a continuation of studies on overvoltage. Attention is confined here to the natural decay on open circuit of cathode potentials at platinized platinum electrodes. Four factors were altered: first, a still solution saturated with hydrogen was used; second, a stirred solution saturated with hydrogen; third, a still solution saturated with nitrogen; and fourth, a stirred solution saturated with nitrogen. The object in each case was to produce a condition that would influence the rate of diffusion of active material away from the electrode-solution interface. Previous experiments had indicated that cathode polarization potentials are determined by the activity of atomic hydrogen and hydrogen ions at the electrode-solution interface. The work was designed to provide information on this theory. All of the data obtained support the theory. * This paper constitutes a portion of the dissertation submitted by Myron B. Towns to the Faculty of the Horace H. Rackham School of Graduate Studies, University of Michigan, in partial fulfillment of the requirements for the Ph.D. degree. Manuscript

This paper is a study of the influence on cathode charge curves, for platinized platinum cathodes in 2 N H2SO4, of conditions that alter the hydrogen concentration on the solution side of the electrode-electrolyte interface. The purpose is to secure information relative to a theory of polarization potential proposed in a previous paper by the senior author. The results show definitely that the cathode potential, both below and above the so-called reversible value, can be materially altered for a given current density by conditions on the solution side of the interface which influence the rate of diffusion of hydrogen away from or to the interface. The changes produced are all such as were expected on the basis of the proposed theory. * This paper constitutes a portion of the dissertation submitted by Myron B. Towns to the Faculty of the Horace tI. Raekham School of Graduate Studies, University of Michigan, in partial fulfillment of the requirements for the ]Ph.D. degree. Manuscript

A study is made of the changes in potential with time of a platinized platinum electrode in acid solution as current is passed through it, sometimes in the cathodic direction and sometimes in the anodic direction. The solution is at all times saturated with nitrogen. In some cases the solution is still and in others it is stirred. All of the curves can be duplicated surprisingly well. Coulombs involved in certain stages of the processes were calculated. Really quantitative results are obtainable. The data appear to support the theory proposed in previous papers for the mechanism of electrode potential and overvoltage.