Oxidized‐State Accumulation Controls Water Oxidation Kinetics on a Model Iridium Atomic Array

Key Points

• The study aims to explore how oxidized-state accumulation influences water oxidation kinetics using an iridium atomic array.
• Utilized a model iridium atomic array as a catalyst in proton exchange membrane water electrolyzers.
• Evaluated catalytic activity and durability at varying cell voltages and current densities.
• Analyzed the kinetics of multi-electron reactions focusing on charge-controlled mechanisms.
• Achieved industrial-level current densities at low cell voltages with the catalyst.
• Demonstrated a significant impact of purely chemical steps on the kinetics of water oxidation reactions.
• Provided molecular insights into the control of water oxidation kinetics through oxidized-state accumulation.