(510a) Unraveling Fundamental Activity-Stability Relationships in Rutile Oxides

Despite the growing demand for green H₂, the United States continues to produce 95% of its H₂ through methane steam reforming, resulting in the annual release of approximately 108 metric tons of CO₂. Water electrolysis offers a promising solution to significantly reduce CO₂ emissions in H₂-intensive processes. However, industrial-scale electrolyzers largely use alkaline electrolysis despite acidic polymer electrolyte membrane (PEM) electrolyzers showing better performance, as PEM electrolyzers are hindered by the high cost and anodic corrosion of precious metal catalysts like Ir and Ru. Of the possible anodic catalysts, IrO₂ is the most stable but still corrodes at the high overpotentials necessary for industrial-level current densities. While efforts have been made to explain and predict experimental oxygen evolution reaction (OER) activity trends, stability challenges, which are crucial for device lifetime and economic viability, have been largely overlooked. To achieve Department of Energy targets of reducing the cost of green H₂ from ~$5/kg to ~$1-2/kg, it is crucial to gain atomic-level insights into how IrO₂ catalyzes the OER and concomitant dissolution processes. Without such knowledge, progress towards these targets is likely to remain limited. In this work, we develop a novel computational reference electrode which enables facile determination of corrosion energetics. Utilizing this development, we identify structure-property relationships controlling activity and stability trends on rutile oxides. We find that, depending on local electronic structure perturbation, OER activity and corrosion may not necessarily be intrinsically coupled. Our findings pave the way towards development of PEM electrolyzer anodes with enhanced stability without compromising activity – an important step towards meeting federal green H₂ price targets.