Influence of iridium oxide loadings on the performance of PEM water electrolysis cells: Part II – Advanced oxygen electrodes

The purpose of this research paper is to report on the applicability of micro-sized titanium particles as the support of IrO2 particles at the anode of PEM water electrolysis cells. A PEM single cell containing only 0.1 mg cm−2 of IrO2 as anode catalyst and 50 wt.% metallic Ti achieved 1.73 V at 1 A cm−2 and 80 °C. Such level of performance is similar to those usually obtained with conventional loadings of several mg cm−2 of IrO2 at the anode side. SEM observations and EIS measurements revealed that the micro-sized titanium particles added to the anodic catalyst layer favor an intimate electrical contact between the catalyst layer and the current collector, and contribute to the reduction of the ohmic resistance of the catalytic layer. A long-term water electrolysis experiment using IrO2/Ti as anode material demonstrated a good stability of the MEA over 1000 h of operation. Using such a low IrO2 loading (0.1 mg cm−2 IrO2), the degradation rate measured at 1 A cm−2 was reduced from 180 μV h−1 (measurement made on pure IrO2 anode) down to only 20 μV h−1 for the 50 wt.% IrO2/Ti anode.