Bio-inspired highly active catalysts for oxygen reduction reaction in alkaline electrolyte

A novel non-platinum oxygen reduction reaction (ORR) catalyst was synthesised by the pyrolysis of carbon-supported vitamin B12 under ammonia atmosphere. The resultant catalyst was characterised by transmission electron microscopy (TEM), scanning TEM (STEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) analyses. Results demonstrated that the catalyst had a spherical structure. XPS revealed that the nitrogen configuration was changed after pyrolysis, and nitrogen species played a key role in catalysing the ORR. The catalyst exhibited an enhanced ORR activity than commercial 20% Pt/C in alkaline media. The catalyst had an electron transfer number of 3.9, which was very close to the ideal theoretical value of 4. Moreover, the catalyst displayed superior methanol tolerance to Pt/C in alkaline medium, demonstrating its potential application as a cost-effective catalyst for direct methanol alkaline fuel cells.