Key Words:DOPED CARBON NANOTUBES; REDUCTION REACTION; ORR ELECTROCATALYST; MESOPOROUS CARBON; NITROGEN; CATALYSTS; PERFORMANCE; ALKALINE; NANOPARTICLES; NANOFIBERS

Abstract:Zeolitic imidazolate frameworks (ZIFs) are already utilized to synthesis precursors for transition metal and nitrogen co-doped carbon catalysts. However, there are few reports on deliberately tailoring catalyst structure except for the hierarchical pores formed from Zn evaporation during the pyrolysis. Herein, NaCl salt-assisted carbonization and unfolding of Fe, Co-codoped ZIF-8 polyhedron (FeCo/ZIF-8) result in ultra-thin Fe, Co, N-codoped graphite flake (FeCo/NG), while FeCo/ZIF-8 pyrolysis without NaCl yields Fe, Co, N-codoped carbon spheres (FeCo/NC). Because of the high specific surface area, porosity, and degree of defects, the active site is further exposed. The synthesized FeCo/NG demonstrates excellent oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) properties with half-wave potential (E-1/2) at 0.88 V and overpotential at 460 mV and good cycling stability, superior to those of FeCo/NC. In addition, the assembled Zn-air batteries with FeCo/NG catalysts deliver high peak power density at 109 mW cm(-2), specific capacity at 783 mAh g(-1) and an operating time for 100 h. The study will provide a feasible synthesis method to design high-performance electrocatalysts by deliberate tailoring structures with molten salt-assisted carbonization and unfolding of ZIFs. (C) 2022 Published by Elsevier B.V.

Volume:920

Issue:

Translation or Not:no