Iridium Oxide and Niobium-Doped Iridium Oxide Anodes for PEM Water Electrolysis: Towards Sustainable Hydrogen Production with Superior Performance

The global push towards cleaner energy sources has heightened the demand for high-performing, durable proton exchange membrane water electrolyzer (PEMWE) electrocatalysts. Green hydrogen, generated through water electrolysis powered by renewable energy, stands as a prominent solution in this endeavor to transition away from fossil fuels. Among various electrolyzer technologies, PEMWE systems currently offer the most competitive pathway for green hydrogen production. These systems typically employ a platinum on carbon supported (Pt/C) cathodic electrocatalyst for the hydrogen evolution reaction (HER) and an iridium oxide (IrOx) anodic electrocatalyst for the oxygen evolution reaction (OER). Efforts to enhance PEMWE performance primarily focus on improving the kinetics of the OER process, which accounts for the majority of activation overpotential during operation. To address cost concerns associated with IrOx, researchers are exploring alternative formulations, including doping with materials like niobium (Nb), aiming for comparable performance at reduced Ir loading [1], [2], [3]. It is argued that higher surface area and lower crystalline IrOx catalysts lead to lower activation overpotentials and enhanced durability, respectively. In this study, we investigate the performance of high-surface-area IrOx electrocatalysts (>200 m 2 /g) and Nb-doped IrOx variants, comparing them with commercially available benchmarks. Through rigorous examination utilizing Rotating Disk Electrode (RDE), Gas Diffusion Electrode (GDE) half-cell, and Membrane Electrode Assemblies (MEAs), we report on the performance and stability of our in-house prepared materials. Preliminary results examining various loadings of IrOx suggest that lower loadings lead to durable and active electrocatalyst layers. Our findings underscore the potential of Nb-doped IrOx as a cost-effective alternative for PEMWE electrocatalysts, offering promising advancements in the pursuit of efficient and sustainable hydrogen production. References: [1] C. Baik, S. W. Lee, and C. Pak, “Glycine-induced ultrahigh-surface-area IrO2@IrOx catalyst with balanced activity and stability for efficient water splitting,” Electrochim Acta , vol. 390, Sep. 2021, doi: 10.1016/j.electacta.2021.138885. [2] K. Zhang et al. , “Status and perspectives of key materials for PEM electrolyzer,” Nano Research Energy , vol. 1, no. 3. Tsinghua University Press, Dec. 01, 2022. doi: 10.26599/NRE.2022.9120032. [3] X. Duan et al. , “Boosting t