Joseph H. Christie

Application of double potential-step chronocoulometry to the study of reactant adsorption. theory

Abstract The theory of a new technique for the study of reactant adsorption is developed. It is shown that a rigorous double-layer correction can be made and that a quantitative determination of the amount of reactant adsorption is possible. By combination of this technique with other methods, such as the drop-extrusion method, for the determination of double-layer charge, it is possible, in some cases, to determine the amounts of both reactant and product adsorbed.

The application of double potential-step chronocoulometry to the study of chemical reactions following the electrode reaction theory

Abstract The theoretical relations for the study of following and catalytic chemical reactions by the new technique of double potential-step chronocoulometry have been developed. Working curves for the evaluation of (pseudo-) first-order rate constants are presented. It is suggested that this technique will compare favorably with other electrochemical techniques for the study of chemical reactions coupled with the electrode reaction.

Theory of staircase voltammetry

Abstract The theoretical relationships for voltammetry with a staircase potential function are developed for a reversible electrode reaction and are shown to be in accord with experiment. Current-potential curves are calculated and tabulated.

The application of double potential-step chronocoulometry to the study of catalytic reactions : the Ti(III)-hydroxy lamine reaction

Abstract The theoretical relationships for the double potential-step chronocoulometry applied to the study of catalytic reactions were verified by an investigation of the Ti(III)-hydroxylamine reaction. The kinetic para-meters obtained in this investigation are: K298 = 43.4±1.1 l/mole sec Ea = 17.2± 1.1 kcal/mole where k298 is the rate constant at 25° and Ea is the Airhenius energy. Previously-reported values of k298 are in excellent agreement with the value reported here but the previously-reported value for the Arrhenius energy appears to be inexplicably in error.

Alternative reaction pathways in potential-step chronocoulometry

Summary Equations have been derived which predict the distribution of current and charge between two alternative electrochemical reaction pathways for the oxidation of a single species under the conditions of potential-step chronocoulometry. It is shown that the percentage of the total charge consumed in each reaction is given exactly by a simple heterogeneous rate constant ratio for the limiting cases of charge transfer control (no concentration polarization) and diffusion control (complete concentration polarization) under conditions where the backward reactions can be ignored, and for totally irreversible reactions (i.e. mixed control with negligible back reactions). The product distribution is approximated by this ratio over a wide range of variation of the kinetic parameters. Examples are given of the dependence of the product distribution on the step potential and the kinetic parameters for the two reaction pathways.