Preparation and Application of IrO2/Pt Electrocatalyst for Regenerative Fuel Cells

Electrocatalysts of the type Pt-IrO2 (at different concentrations) have been synthesized and characterized in Regenerative Fuel Cell (RFC) configuration. Commonly IrO2 has been mainly used as oxygen evolution electrocatalyst. These oxide-metal mixtures were prepared by incipient wetness technique and characterized by XRD and SEM, obtaining in all cases nanoparticles. The powder materials were impregnated by hot-spray technique on Nafion 117 in order to evaluate water electrolysis/fuel cell performance. The catalyst loading in oxygen electrodes was about 6 mg•cm-2. Water electrolysis/fuel cell performance has been evaluated using a single cell test fixture with a geometric area of 5 cm2. It is derived that for fuel cell operation an excess of Pt favours the oxygen reduction process whereas IrO2 promotes oxygen evolution.