Atomic-scale structure and composition of Pt3Co/C nanocrystallites during real PEMFC operation: A STEM-EELS study

- Atomic-scale structural and compositional changes of Pt3Co/C nanoparticles during PEMFC operation.
- Formation of Pt, Pt-Co/C “hollow”, Pt-Co core-shell and Pt “bulk” nanoparticles.
- Hollow nanoparticles are Co poor and feature large size.
- Relation between the Pt-shell thickness and the size of the hollow nanoparticles.
- The ORR activity of the “hollow” Pt/C nanoparticles is 3-fold that of “bulk” Pt/C.