Investigation of Metal-Doped IrO₂ in Rotating Disk Electrode and Membrane Electrode Assembly Configurations for Acidic Oxygen Evolution Reaction

As the most promising technique for green hydrogen production, proton exchange membrane water electrolysis (PEMWE) has received extensive attention. However, its development is hindered by oxygen evolution reaction electrocatalysts with high cost, like IrO2. Although doping heteroatoms is an effective strategy to reduce Ir content, most research has only focused on one certain doped element and not compared the effects of different elements. In addition, the performance of doped catalysts is mainly measured in a rotating disk electrode (RDE) configuration instead of a membrane electrode assembly (MEA) configuration. In this work, IrO2 was doped with three metal elements (Co, Ni, and Cu) and was supported on TiO2 to maximize the utilization of active sites. RDE tests indicated that Ir3Ni1Ox/TiO2 had the fastest kinetics (40.65 mV dec–1) and the highest activity (314.9 A gIr–1 at 1.53 V), further confirmed in a MEA setup with the lowest cell potential. Physical characterizations demonstrated that its high performance possibly originated from the hydroxylated NiO component, which would lead to high OH fraction on the catalyst surface. Overall, our study highlights the investigation of catalytic performance in both RDE and MEA setups, providing comprehensive information for actual application of metal-doped IrO2 in PEMWE.