Potential-dependent O–O Coupling Mechanism for Oxygen Evolution Reaction on Ruthenium Dioxide

Designing alternative OER catalysts to IrO₂ has been a long-standing and compelling task in proton exchange membrane water electrolysis (PEM-WE). Currently, the more active and less expensive RuO₂ has attracted extensive attention, with the primary consideration being how to improve its long-term stability. Thus, disclosing the underlying factors and mechanisms contributing to its high activity and low stability is significant. Herein, we employ Grand Canonical density functional theory (GC-DFT) calculations and microkinetic modeling (MKM) to comprehensively elucidate the potential-dependent oxygen evolution reaction (OER) mechanisms on the RuO₂(110) facet. Our results confirm the dominant role of AEM and the less likely occurrence of LOM and OPM on the pristine RuO₂(110) surface. This work not only deepens the mechanistic understanding of OER on RuO₂ from both thermodynamic and kinetic perspectives but also provides a basis for achieving a rational design of high-performance OER electrocatalysts.