Fog-like fluffy structured N-doped carbon with a superior oxygen reduction reaction performance to a commercial Pt/C catalyst

Abstract

A high-performance N-doped carbon catalyst with a fog-like, fluffy structure was prepared through pyrolyzing a mixture of polyacrylonitrile, melamine and iron chloride. The catalyst exhibits an excellent oxygen reduction reaction (ORR) performance, with a half-wave potential 27 mV more positive than that of a commercial Pt/C catalyst (−0.120 vs. −0.147 V) and a higher diffusion-limiting current density than that of Pt/C (5.60 vs. 5.33 mA cm⁻²) in an alkaline medium. Moreover, it also shows outstanding methanol tolerance, remarkable stability and nearly 100% selectivity for the four-electron ORR process. To our knowledge, it is one of the most active doped carbon ORR catalysts in alkaline media to date. By comparing catalysts derived from precursors containing different amounts of melamine, we found that the added melamine not only gives the catalyst a fluffy structure but also modifies the N content and the distribution of N species in the catalyst, which we believe to be the origins for the catalyst's excellent ORR performance.