Electron beam induced radiation damage in the catalyst layer of a proton exchange membrane fuel cell
Article first published online: 29 JUL 2013
© 2013 Wiley Periodicals, Inc.
Volume 36, Issue 3, pages 338–346, May/June 2014
How to Cite
He, Q., Chen, J., Keffer, D. J. and Joy, D. C. (2014), Electron beam induced radiation damage in the catalyst layer of a proton exchange membrane fuel cell. Scanning, 36: 338–346. doi: 10.1002/sca.21117
- Issue published online: 4 JUN 2014
- Article first published online: 29 JUL 2013
- Manuscript Accepted: 28 JUN 2013
- Manuscript Received: 23 MAY 2013
- National Science Foundation. Grant Number: DGE-0801470, OCI 07-11134.5
- radiation damage;
- catalyst layer;
Electron microscopy is an essential tool for the evaluation of microstructure and properties of the catalyst layer (CL) of proton exchange membrane fuel cells (PEMFCs). However, electron microscopy has one unavoidable drawback, which is radiation damage. Samples suffer temporary or permanent change of the surface or bulk structure under radiation damage, which can cause ambiguity in the characterization of the sample. To better understand the mechanism of radiation damage of CL samples and to be able to separate the morphological features intrinsic to the material from the consequences of electron radiation damage, a series of experiments based on high-angle annular dark-field–scanning transmission scanning microscope (HAADF-STEM), energy filtering transmission scanning microscope (EFTEM), and electron energy loss spectrum (EELS) are conducted. It is observed that for thin samples (0.3–1 times λ), increasing the incident beam energy can mitigate the radiation damage. Platinum nanoparticles in the CL sample facilitate the radiation damage. The radiation damage of the catalyst sample starts from the interface of Pt/C or defective thin edge and primarily occurs in the form of mass loss accompanied by atomic displacement and edge curl. These results provide important insights on the mechanism of CL radiation damage. Possible strategies of mitigating the radiation damage are provided. SCANNING 36:338–346, 2014. © 2013 Wiley Periodicals, Inc.