AC Impedance Study of the Electrochemical Behavior of Hydrogen/Oxygen Gas Mixture at Nafion/Catalyst Electrode Interface

The anodic reaction of hydrogen/oxygen gas mixture at platinum or palladium electrode interfacing with a solid polymer electrolyte was investigated using AC impedance method. The impedance spectrum of the electrode reactions of the mixture depends on the gas composition, electrode roughness, the mode of electrochemical operation and the cell potential. For electrolysis mode of operation, the spectrum taken for the reaction on a rough platinum electrode for the gas mixture revealed clearly that the local anodic reduction of oxygen gas takes place concurrently with the anodic oxidation of hydrogen gas.