Tri-doped mesoporous carbon nanostructures prepared via template method for enhanced oxygen reduction reaction

Abstract

Doped carbon structures have been developed as non-precious metal catalysts for oxygen reduction reactions (ORR) in polymer electrolyte membrane fuel cells (PEMFCs). Among doped carbon structures, Fe- and N-doped carbon (Fe/N/C) nanostructured catalysts have received attention due to their catalytic activity, comparable to that of Pt, avoiding the use of critical raw materials. However, obviously, its durability is not yet neither fully understood nor comparable to that of traditional catalysts. In this study, we synthesized mesoporous F-doped Fe/N/C, which is a tri-doped carbon nanostructure, as a cathode catalyst for ORR. Tri-doped carbon catalysts with different amounts (x) of F (Fx-Fe/N/C) were prepared using Fe-5,10,15,20-tetrakis(4-methoxyphenyl)-21H,23H-porphine iron(III) chloride and NH4F as the Fe/N- and F- doping sources, respectively, and Santa Barbara amorphous-15 as the template. Fx-Fe/N/C with an optimal F content exhibited excellent electrocatalytic performance for ORRs i.e. a high half-wave potential of 809 mV in 0.1 M HClO4 solution, a maximum power density of 280 mW cm(-2), and a high stability for 4000 min at 0.5 V, owing to the high proportion of FeNx and pyridinic N as active sites, strong C-F bonds, and hydrophobic surfaces.