Twin Boundary-Induced Corrosion Kinetics of Icosahedral Core–Shell Structure Unveiled by In Situ Liquid Transmission Electron Microscopy

Icosahedrons with a high density of twin boundaries exhibit high performance in oxygen reduction reaction (ORR) but might be considered to exhibit poor stability due to the selective dissolution of Pd atoms from the cores through the twin boundaries. Here, we utilize in situ liquid cell transmission electron microscopy (LC-TEM) to monitor the corrosion behavior of icosahedral Palladium@Platinum (Pd@Pt) core–shell nanoparticles in real time. We demonstrated that twin boundaries bring in numerous defects as the initial corrosion sites and high-strain agglomeration to accelerate the corrosion compared to the octahedrons. After the twin boundaries’ corrosion finishes, the high curvature (HC) path appears and plays a vital role during corrosion. Those insights help us to further understand the effect of twin boundaries on catalyst degradation and engineer durable morphology-controlled Pd@Pt nanoparticles.