Strain-Induced Corrosion Kinetics at Nanoscale Are Revealed in Liquid: Enabling Control of Corrosion Dynamics of Electrocatalysis

Summary Corrosion of nanoparticles during electrocatalysis, such as oxygen reduction reaction (ORR), occurs at the nanoscale and is vital for catalyst stability. Here, using liquid cell (LC) transmission electron microscopy (TEM), we study the corrosion process of palladium@platinum (Pd@Pt) core-shell octahedra in real time and reveal that both the static local strain and the evolving curvature synergistically control the nanoscale corrosion kinetics. Specifically, in locations with tensile strain and high local curvature, the etching process is much faster. Density functional theory (DFT) calculation suggests that the dissolution potential of the Pd nanocrystal decreases as the strain increases; meanwhile, Pd atoms tend to be corroded more easily on a surface under tensile strain than on one under compressive strain. With these insights on the corrosion mechanism at the nanoscale, we subsequently designed and synthesized nanoparticles with smaller strain, and these showed higher durability in both an in situ LC study and an ex situ ORR stability test.