Comparative IL-TEM Study Concerning the Degradation of Carbon Supported Pt-Based Electrocatalysts

The identical location transmission electron microscopy (IL-TEM) approach is used for a comparative study of the degradation of several standard Pt-based electrocatalysts for low temperature proton conducting membrane fuel cells (PEMFCs). By comparing the quantitative Pt surface area loss with IL-TEM micrographs, it is shown that in accelerated stress tests particle migration and coalescence as well as particle detachment are the main degradation channels for the chosen catalysts. No unambiguous indication for a major contribution of Pt dissolution to the surface area loss is found. Furthermore, it is demonstrated that seemingly similar catalysts can exhibit under identical treatment pronounced differences in their degradation behavior. A finding questioning the common praxis of comparative catalyst studies without full disclosure and discussion of their synthesis. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.035206jes] All rights reserved.