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 .