F127 Assisted Synthesis of Tri-(Fe/F/N)-doped Porous Carbons with a High Density of Fe3C and Fe-N4 Catalytic Sites as Efficient Electrocatalysts for ORR

Abstract

Because of the slow reaction rate of the oxygen reduction reaction (ORR), high-performance catalysts are needed to accelerate the reaction. However, platinum (Pt)-based electrocatalysts have the shortcomings of high cost and poor stability. The development of low-cost, high catalytic activity and long-term durability non-precious metal electrocatalysts has become a research hotspot. In this study, we successfully prepared tri(Fe/N/F)-doped FeNF-F127C catalyst featuring mesoporous carbon via polyacrylonitrile/polyvinylidene fluoride/F127 (PAN/PVDF/F127) tricomponent polymers and iron(III) nitrate nonahydrate (Fe(NO3)3•9H2O) followed by thermal carbonization. Compared with commercial Pt/C catalysts, FeNF-F127C showed excellent long-term durability and considerably better methanol tolerance as well as a high electrocatalytic activity (Eonset: 0.956 V vs RHE, E1/2: 0.823 vs RHE, and electron transfer number: 4.0) in alkaline media. The improved ORR performance could be explained by larger specific surface area with a well-ordered mesoporous structure, high density of Fe3C sites and Fe-N4 sites.