Activity and Stability of Iridium-Based Alloy Catalysts for PEM Electrolyzer

Bi-metallic alloy of Ir 3 Cr and Ir 3 Pt catalysts as well as Ir black as reference were synthesized by co-reduction route in sodium borohydride under hydrothermal condition. Well-distributed particles in the range of 1.7 - 2 nm in average were yielded. Ir alloy formation was confirmed by XRD spectra. Interestingly, after 1000 ADT cycle under half cell condition, Ir 3 Cr catalyst showed an enhanced activity of 7% and 59% for OER at 1.6 V compared to Ir 3 Pt and as prepared Ir black, respectively. Moreover, both alloy catalysts exhibited excellent stability with ~10 and 40 mV less overpotential for OER at 20 mA cm -2 compared to as-synthesized Ir black and commercial Ir black catalysts.