Anodic dissolution of adsorbed hydrogen

Abstract

Hydrogen adsorption isotherms have been determined on catalyzed carbon electrodes. Curves similar to the Freundlich isotherm were obtained and at atmospheric pressure 4 ml g^–1 of dry hydrogen was adsorbed, but when the electrode was wetted with potassium hydroxide solution the adsorption increased to a total of 14.0 ml g^–1. The electrodes were discharged at constant current and a linear relationship was observed between the working potential and the quantity of electricity passed over the voltage range 0.05–0.9 V. This relationship was independent of current density. When the current was reversed and the electrode cathodized a similar linear relationship having the same gradient was observed. Electrodes on which measured amounts of hydrogen were adsorbed were discharged to various fixed potentials and the amount of hydrogen consumed was deduced from the amount which the electrode would re-adsorb. It was found that the potential of the electrode was linearly related to the amount of hydrogen adsorbed on it.