Nitrogen-Doped Hollow Carbon Nanoparticles with Excellent Oxygen Reduction Performances and Their Electrocatalytic Kinetics

To propel the commercialization of fuel cells, the development of efficient nonprecious metal catalysts, specifically cathodic oxygen reduction catalysts, is turning into reality because the great advancements have been made on nitrogen-doped carbon materials recently. In this study, we demonstrated that nitrogen-doped hollow carbon nanoparticles (N-HCNPs) exhibit excellent electrocatalytic performance for oxygen reduction reaction (ORR) in alkaline fuel cells. Cyclic voltammetry and rotating ring-disk electrode voltammetry showed that the ORR activity of N-HCNPs approaches that of commercial Pt-C catalyst and is much better compared with nitrogen-free counterparts due to the incorporation of nitrogen atoms into graphitic structures. Kinetic studies indicated that the involvement of nitrogen induces a totally different oxygen adsorption mechanism and a four-electron dominated reaction pathway for N-HCNPs in comparison with nitrogen-free HCNPs, very similar to the observations in Pt-C. Moreover, N-HCNPs exhibited good operation stability and excellent tolerance to methanol crossover and CO poisoning for ORR superior to that of Pt-C. Our findings suggest that N-HCNPs catalyst is a promising alternative for the Pt-based catalysts in fuel cells.