Atomically Dispersed Fe-Nx Active Sites within Hierarchical Mesoporous Carbon as Efficient Electrocatalysts for Oxygen Reduction Reaction
It remains a great challenge to develop highly efficient catalysts with earth abundant materials to replace the precious platinum group metal (PGM) catalysts for oxygen reduction reaction (ORR). Here, we report a self-sacrificing template strategy to synthesize hierarchical mesoporous carbon materials with atomically dispersed Fe-Nx active sites. Derived from the Fe-polydopamine precursor obtained via in-situ polymerization of dopamine and etching of cobalt-template using a FeCl3 solution, the resultant catalyst shows a high specific surface area (1229.3 m2 g-1), a hierarchical mesoporous structure, an improved hydrophilicity, and abundant atomically dispersed Fe-Nx active sites. As a result, the single atom catalyst exhibits a remarkable activity and durability in 0.1 M KOH with an onset and half-wave potential of 1.03 and 0.88 V, respectively, which outperforms its commercial Pt/C counterpart. In acid and neutral media, the catalyst also demonstrates a comparable electrocatalytic activity yet much greater durability than that of the commercial Pt/C. This work opens a new avenue for synthesis of cost-effective catalysts at atomic scale for efficient energy conversion.