Co on porous carbon network derived from ZIF-8 for oxygen reduction and evolution reaction in alkaline solution.

[Display omitted] • Highly porous carbon network was derived from zeolitic-imidazole frameworks. • Co-deposition on porous carbon enhanced the catalytic activity. • Co on carbon was electrochemically stable as cathode material during 520 h cycling. Porous carbon wrapped on cobalt catalyst is one of the promising candidates to replace noble metal-based catalysts for ORR. Herein, a porous carbon network (PCN) was obtained by synthesis of zeolitic-imidazole frameworks (ZIF-8) followed by pyrolysis at 1050 ℃ under a nitrogenous atmosphere and the cobalt (Co) was deposited on PCN to obtain Co-PCN by sequential reduction method. The PCN showed a relatively high specific surface area of 806.43 m2/g and decreases to 329.4 m2/g with the introduction of Co contents in PCN. The Co-PCN reveals excellent performance having a current density of 350 mA cm−2 for the ORR at 0.5 V after 20th cycles as a cathode material in rechargeable zinc-air batteries. [ABSTRACT FROM AUTHOR]