Dresden 2026 – scientific programme

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O: Fachverband Oberflächenphysik

O 13: Solid-liquid interfaces: Reactions and electrochemistry I

O 13.1: Talk

Monday, March 9, 2026, 15:00–15:15, TRE/PHYS

The Weak Spots of IrO₂: Sampling Defect Landscapes at Operation Conditions — •Jimiben V. Patel, Nikhil Bapat, Karsten Reuter, and Hendrik H. Heenen — Fritz-Haber-Institut der MPG, Berlin

Under the harsh oxidative potentials required for the oxygen evolution reaction, rutile IrO₂ surfaces undergo restructuring that leads to Ir dissolution and undermines catalyst durability, eventually impacting device performance. To mitigate the catalyst degradation via robust design principles, a fundamental atomistic understanding of how surface reconstructions initiate and propagate dissolution is urgently needed. Since high-resolution operando characterization remains challenging, atomistic simulations are essential for uncovering the underlying microscopic mechanisms. However, achieving realistic insight requires approaches that go well beyond conventional, idealized modeling frameworks. In this work, we employ machine-learned interatomic potentials trained on density-functional theory to systematically sample vacancy formation across a wide range of electrochemical environments. This allows us to resolve how surface defects nucleate, interact, and evolve under relevant oxidizing conditions. We find that vacancy formation becomes increasingly favorable at higher potentials, with isolated defects stabilizing and subsequently coalescing into larger surface pits – structures that likely act as precursors for accelerated dissolution. These findings provide a first link between applied potential and defect thermodynamics, offering predictive insight into potential-dependent degradation pathways of IrO₂.

Keywords: Electrochemistry; Dissolution; Sampling; IrO2 OER catalyst; Molecular Dynamics