Polymer electrolyte membrane fuel cells (PEMFCs) have been considered as one of the most promising energy conversion devices for future due to their high efficiency, and environmental friendly system. However, large-scale applications of PEMFCs have still faced some challenges in terms of cost and durability. Catalyst plays a great role in determining cost and durability of PEMFCs. Conventional catalyst for PEMFCs is a state-of-the-art carbon supported platinum nanoparticles (Pt/C). Pt/C has an outstanding catalytic activity for both hydrogen oxidation reaction (HOR) at anode and oxygen reduction reaction (ORR) at cathode. But, high price of Pt is a major contributory factor in increasing PEMFCs cost. And, conventional carbon support is vulnerable to corrosion under oxidative potential, which leads to serious degradation of cell performance. Therefore, it has been one of the major issue in PEMFCs to develop low-priced and durable catalysts without sacrificing catalytic performance. Recent studies proposed that co-doping of transition metal (Fe, Co, Mn..) and nitrogen into graphene-like carbon structure can draw remarkable ORR activity under PEMFCs operating conditions. In addition, this graphene-like carbonaceous materials also can have higher corrosion resistance than conventional carbon support with amorphous structure.

Herein, we synthesized iron (Fe) and nitrogen co-doped carbon nanofiber (Fe-N-CNF) with highly porous structure as efficient oxygen reduction reaction catalyst and durable support for platinum catalyst. We could successfully synthesize porous CNF by using silica nanoparticles (SiO₂ NPs) as sacrificing materials. After leaching of SiO₂ NPs, BET surface area and electrochemical surface area (ECSA) were 3-times and 6-times enhanced, respectively. So, porous Fe-N-CNF has excellent ORR activity and durability in acidic media.

Fig. 1. TEM images of Fe-N-CNF and porous Fe-N-CNF