CoFe/N, S–C Featured with Graphitic Nanoribbons and Multiple CoFe Nanoparticles as Highly Stable and Efficient Electrocatalysts for the Oxygen Reduction Reaction

[Image: see text] The stability and activity of the catalysts are crucial for the oxygen reduction reaction (ORR) in fuel cells. Herein, CoFe/N, S-codoped biomass carbon (FB-CoFe-700) with graphitic nanoribbons and multiple CoFe nanoparticles was prepared through a facile thermal pyrolysis followed by an acid treatment process. The evolution of the growth of metal nanoparticles with the formation of graphite during the carbonization process was investigated. Inseparable from graphitic carbon-encased metal nanoparticles with the coexistence of graphitized nanoribbons and graphene-like sheets, FB-CoFe-700 exhibited a remarkable long-term electrocatalytic stability with 90.7% current retention after 50 000 s much superior to that of the commercially available Pt/C (20 wt %) in an alkaline medium. Meanwhile, FB-CoFe-700 displayed promising ORR catalytic activity (E(0) = 0.92 V vs reversible hydrogen electrode (RHE), E(1/2) = 0.82 V vs RHE, and n = 3.97) very similar to that of commercial Pt/C and outstanding methanol tolerance in an alkaline medium. This work is helpful for further development of nonprecious metal-doped carbon electrocatalysts with long-term stability.