Electrical performance of an electrochemical cell operating either as water electrolyser or as mixed cell for oxygen consumption from the fed air stream is presented. Utilization of PEM-electrolyser technology can explain that the performance is better in electrolyser configuration. Operating temperature slightly improves the yields. For photobiological applications, the cell would be used as oxygen regulator of the CO2 enriched vapor phase. The present investigation validates that the presence of CO2 in air stream does not affect the cell performance. Steady voltammetry and impedance spectroscopy performed for the two configurations allow to deduce, in a first part, kinetics of oxygen evolution in electrolyser mode, considering hydrogen evolution from the literature. The case of mixed cell operation was thereafter considered, using the deduced law for the anode. Subtracting the anode part from the overall response of the cell led to estimate for the kinetic law of oxygen reduction. The cathode resistance calculated from the law is in good agreement with the cathode resistance determined from EIS.
