Layered-Template Synthesis of Graphene-like Fe-N-C Nanosheets for Highly Efficient Oxygen Reduction Reaction

A general layered-template strategy has been developed to construct graphene-like Fe-N-C nanosheets (g-Fe-N-CNS) by lamellar confinement of layered clay montmorillonite (MMT) using iron complexes as precursors. During pyrolysis, iron complexes could be transformed into atomically dispersed Fe and N co-doped carbon nanosheets in the interlayer space of MMT. After removing the MMT template, the as-fabricated g-Fe-N-CNS exhibited excellent ORR performance with a more positive half-wave potential (E_1/2) of 0.87 V, good stability, and superior methanol tolerance. Furthermore, g-Fe-N-CNS assembled as the air cathode also exhibits encouraging performance in the primary Zn–air batteries. These excellent ORR performances are ascribed to the high specific surface area, hierarchically mesoporous structure, unique 2D nanosheet architecture, and uniformly dispersed Fe-N active sites. Besides, the calculation results indicate that with the ORR process on Fe-N active sites, the adsorption of *OOH is the most crucial step in determining the reaction rate on g-Fe-N-CNS. This layered-template approach provides a general synthetic methodology toward 2D heteroatom-doped carbon nanosheets for highly efficient energy conversion.