Enzymolytic lignin derived Fe–N codoped porous carbon materials as catalysts for oxygen reduction reactions

Numerous active sites and hierarchical pore structures are important for improving catalytic performance for the oxygen reduction reaction (ORR). In this work, a series of iron-nitrogen-doped porous carbon materials (Fe–N–C) with ORR catalytic activity were prepared by a one-step pyrolysis method using enzymolytic lignin as the raw material, soy protein isolate and iron chloride as dopants. The results showed that the samples with the best performance have abundant Fe-Nx active sites and mesoporous structures. At the same time, the electrocatalytic results indicate that the half-wave potential of catalyst was 0.84 V, which reached 96.55% of commercial Pt/C catalysts (E_1/2 = 0.86 V), it still preserves an initial current density of 92%, after 10,000 s of circulation, which is much better than Pt/C (86%). Due to the low cost, high activity and stable ORR property, the prepared non-precious metal electrocatalyst will play an important role in the applications of fuel cells.