Probing the structure, the composition and the ORR activity of Pt3Co/C nanocrystallites during a 3422Â h PEMFC ageing test

- Structure and composition of Pt3Co/C nanoparticles change during a 3422 h PEMFC test.
- Compact hollow nanoparticles form at high cathode potential.
- Hollow Pt/C nanoparticles show higher intrinsic ORR specific activity compared to pure Pt/C.
- Hollow nanoparticles withstand 2000 h of operation without structural degradation.