Facile synthesis of high performance non-noble-metal electrocatalyst Fe-N-S/C for oxygen reduction reaction in acidic solutions

The development of non-noble metal catalysts is of great interest due to their significant potential application in both fuel cell system and metal-air batteries, particularly when considering long term commercial deployment. Fe/N/C is a promising non-Pt electrocatalyst for the oxygen reduction reaction (ORR), but its catalytic activity is considerably inferior to that of Pt in acidic medium. In this paper, an improved Fe/N/S/C catalyst (denoted as Fe-N-S/C) is presented. Nitrogen-sulfur-iron-doped porous carbon material is synthesized by the pyrolysis of dicyandiamide, a kind of abundant and inexpensive compound, with thiourea as additional sulfur source in argon atmosphere. The Fe-N-S/C shows excellent performance for the ORR with the onset and half-wave potential at 0.89 and 0.78 V (vs. RHE) in 0.1 M H2SO4 solution, respectively, which are significantly higher compared to those of the catalysts derived from only dicyandiamide (0.85 and 0.75 V). Our results indicate that as compared to the commercial 20 % Pt/C catalyst, the synthesized catalyst exhibits not only higher current density and long-term durability but also higher tolerance to methanol poisoning. More importantly, the synthetic method is simple and inexpensive.