Fe-, N-Embedded Hierarchically Porous Carbon Architectures Derived from FeTe-Trapped Zeolitic Imidazolate Frameworks as Efficient Oxygen Reduction Electrocatalysts

During the design and construction of an efficient iron-nitrogen-carbon (Fe-N-C) electrocatalyst, it was difficult to avoid the formation of iron oxides along with the hierarchical carbon frameworks containing dispersed FeNx sites. As a result, a slow oxygen reduction reaction (ORR) occurred, making it difficult to improve the electrocatalytic property. Herein, we have successfully synthesized the Fe, N-doped hierarchically porous carbon architectures from FeTe-trapped ZIF-8 coated with polydopamine by heat treatment. During the pyrolysis process, the evaporation of tellurium could inhibit the formation of iron oxides, promote the formation of more FeNx active species, and facilitate the formation of mesoporous structure to accelerate mass transfer and increase the approachability of active species. The resulting Fe, N-doped porous carbon architectures possessed excellent ORR catalytic performance, and the half-wave potential was 10 mV more than that of the precious Pt/C catalysts. Besides, the obtained catalysts present a superb methanol tolerance and long-term durability compared to precious Pt/C catalysts in alkaline media. This work opens up new avenues for the construction of the uniformly dispersed FeNx sites catalysts for ORR.