Atomic Origin of Activity-Stability Trade-Off in Strain-Engineered Pt-Based Oxygen Reduction Catalysts

The activity-stability trade-off in electrocatalysts remains a critical challenge. While compressive strain is known to weaken O* adsorption and enhance oxygen reduction reaction (ORR) activity in platinum (Pt)-based catalysts, its impact on stability is poorly understood. Here, we reveal how compressive strain accelerates surface reconstruction by combining global structural optimization with Pourbaix analysis. Using a Pt(111) surface with −2% compressive strain, we demonstrate that strain induces reconstruction at a lower oxygen coverage via a strain–release mechanism. Pourbaix diagrams further show that strained surfaces undergo oxygen-induced reconstruction at ∼0.1 V lower potentials than unstrained surfaces at 1 monolayer (ML) coverage. These findings uncover the atomic-scale origin of the trade-off: Compressive strain optimizes O* binding for activity but destabilizes the surface under oxidation, promoting premature reconstruction. Our work provides a mechanistic framework for designing strain-engineered Pt catalysts with balanced activity and durability, advancing the rational development of high-performance ORR electrocatalysts.