Degradation Mechanisms of Pt/C Fuel Cell Catalysts under Simulated Start–Stop Conditions

This manuscript investigates the degradation of a Pt/Vulcan fuel cell catalyst under simulated start–stop conditions in an electrochemical half-cell. Identical location transmission electron microscopy (IL-TEM) is used to visualize the several different degradation pathways occurring on the same catalyst material under potential cycling conditions. The complexity of degradation on the nanoscale leading to macroscopic active surface area lossis demonstrated and discussed. Namely, four different degradation pathways at one single Pt/Vulcan aggregate are clearly observed. Furthermore, inhomogeneous degradation behavior for different catalyst locations is shown, and trends in degradation mechanisms related to the…