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.