Abstract
The graphitic-layer encapsulated iron-containing nanoparticles (G@Fe)
have been proposed as a potential type of active and stable non-precious
metal electrocatalysts (NPMCs) for the oxygen reduction reaction (ORR).
However, the contribution of the encapsulated components to the ORR
activity is still unclear compared with the well-recognized surface
coordinated FeNx/C structure. Using the strong complexing effect of the iron component with anions, cyanide (CN−) in alkaline and thiocyanate (SCN−)
in acidic media, the metal containing active sites are
electrochemically probed. Three representative catalysts are chosen for a
comparison including the as-prepared encapsulated G@Fe, commercial
Fe/N/C catalyst with iron–nitrogen coordinated surface functionalities
and molecular iron phthalocyanine (FePc) containing well-defined
structures and compositions. It was found that all samples showed
significant shifts of half-wave potentials indicating that surface Fe
coordinated sites in all cases. The G@Fe catalyst showed the weakest
poisoning effect (the lowest shifts of half-wave potential) compared to
the Fe/N/C and FePc catalysts in both electrolytes. These results could
be explained that the encapsulated iron components influence the FeNx/C and/or NxC surface functionality.
Original language | English |
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Journal | Science Bulletin |
Volume | 63 |
Issue number | 1 |
Pages (from-to) | 24-30 |
ISSN | 2095-9273 |
DOIs | |
Publication status | Published - 2018 |
Keywords
- Encapsulated Fe catalysts
- Oxygen reduction reaction
- Ion poisoning
- Active sites
- NPMCs