In situ surface-confined fabrication of single atomic Fe-N4 on N-doped carbon nanoleaves for oxygen reduction reaction

Controllable fabrication of Fe-N-C based single-atom catalysts (SACs) for enhanced electrocatalytic performance is highly desirable but still challenging. Here, an in situ surface-confined strategy was demonstrated for the synthesis of single atomic Fe-N-4 on N-doped carbon nanoleaves (L-FeNC). The in situ generated Zn-3[Fe(CN)(6)](2) could not only serve as a protection layer against collapse of nanoleaves but also provide abundant Fe source for the formation of Fe-N moieties during pyrolysis, leading to high surface area and high graphitization degree of L-FeNC simultaneously. Benefiting from abundant Fe-N-4 active sites, enhanced mass and charge transfer, the as-prepared L-FeNC manifested a half-wave potential of 0.89 V for oxygen reduction reaction (ORR) in 0.1 M KOH. A maximum power density of 140 mW cm(-2) and stable discharge voltage even after operation for 50,000 s have been demonstrated when the L-FeNC was used as air cathode for Zn-air battery. This work not only provided a unique surface-confined strategy for the synthesis of two-dimensional nanocarbons, but also demonstrated the significant benefit from rational design and engineering of Fe-N-C SACs, thus offering great opportunities for fabrication of efficient energy conversion and storage devices. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

This study demonstrated a controllable in situ surface-confined strategy for the synthesis of single-atom Fe-N-4 on N-doped carbon nanoleaves, leading to high surface area and graphitization degree of L-FeNC. The abundant Fe-N-4 active sites in L-FeNC resulted in enhanced mass and charge transfer, achieving a half-wave potential of 0.89 V for oxygen reduction reaction (ORR) in 0.1 M KOH.