STUDY OF THE OXYGEN ELECTRODE MECHANISM

The processes involved in transporting oxygen from a gas feed stream to reaction sites at the electrode/electrolyte interface are examined. Transfer across the gas/liquid interface and through the bulk solution are well understood, and sufficient data for gas diffusion electrode design are available. A method to study surface migration process is outlined, using double layer capacity measurements to monitor the presence of adsorbed oxygen as a function of time on electrodes of varying geometries. The dependence of the double layer capacity of platinum in acid and alkaline electrolytes on a variety of parameters is explored. A reduced platinum surface is insensitive to oxygen adsorption, but a thin conducting layer of an oxide, which can be formed by a number of oxidizing pretreatments, interacts strongly with dissolved oxygen. The proposed method of examining surface migration cannot be applied to a reduced platinum surface, it is still valid for migration along a conducting oxide. (Author)