Effect of Cobalt Loading in Nitrogen-Doped Carbon on Oxygen Reduction Reaction for PEM Fuel Cells

Abstract

Nitrogen-doped carbon supported Co catalysts (CoNC) were synthesized via condensation reaction of pre-polymer of melamine formaldehyde resin with addition of cobalt nitrate salt, followed by carbonization in nitrogen. Rotating disk electrode technique (RDE) and scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDS) were used to identify the structure and oxygen reduction reaction (ORR) kinetics of the catalysts. The results show that the catalysts with 3.77 wt% Co loading yield the best ORR catalytic activity. Koutecky-Levich plots indicate ORR mechanism is governed by mixed mechanisms and the measured electron number varies between 2 and 4. SEM image shows an irregular lamellar structure of CoNC catalyst formed at high temperature, and different Co loadings in CoNC catalyst do not change its surface morphology.