Influence of physicochemical properties on the performance of Pt/C porous electrodes for oxygen reduction in phosphoric acid

Oxygen reduction on Pt supported on carbon black in PTFE-bonded porous electrodes in 98% H3PO4 at 170°C was investigated. The influence of the Pt surface area and the volume of H3PO4 in the electrode structure (per cent acid occupation, PAO) on the performance of porous electrodes (ie current-potential behavior, potential at a constant current density of 200 mA cm-2, oxygen gain) were evaluated. The results clearly show that the Pt surface area has a major influence on the Tafel slope, electrode polarization, electrode potential decay at constant current density, and oxygen gain. On the other hand, these parameters do not show a clear trend with PAO