Fe-based cathode materials pyrolyzed with a Zn compound such as ZIF-8 are promising as non-platinum oxygen reduction reaction (ORR) catalysts. However, the ZIF-8 is not sufficient to reduce the cost of fuel cells. Here we report new metal/nitrogen/carbon-electrocatalysts synthesized by the pyrolysis of precursors consisting of Ketjenblack®, a Zn complex with 4,4′-bipyridine, 1,10-phenanthroline (phen), and iron(II) chloride, first in argon at 1050 °C, then ammonia at 950 °C. It is elucidated that the addition of the zinc complex and phen to the precursors promotes formation of pyridinic and graphitic nitrogen to improve the ORR activity. The onset potential defined by 100 μA mg−1 for ORR was 0.876 V vs. RHE with the catalyst containing all the ingredients. Based on the results of accelerated durability tests and XPS measurements, it was considered that there were two oxygen reduction catalytic sites consisting of pyridinic and graphitic nitrogen species on the surface of the catalysts.
|Number of pages||8|
|Journal||Materials Science and Engineering B: Solid-State Materials for Advanced Technology|
|Publication status||Published - Feb 2018|
- Fe/N/C catalyst
- Non-platinum catalyst
- Oxygen reduction reaction
- Polymer electrolyte fuel cell