In Situ Anchoring of Zeolite Imidazole Framework-Derived Co, N-Doped Porous Carbon on Multiwalled Carbon Nanotubes toward Efficient Electrocatalytic Oxygen Reduction

Abstract

Carbon nanomaterials doped with nitrogen/transition metals (metal–N–C) are promising to substitute platinum (Pt) for catalyzing the oxygen reduction reaction (ORR). Metal–N–C can be effectively derived from pyrolysis of metal–organic frameworks but usually suffers from microscale aggregation. Herein, we report an in situ approach to anchor zeolite imidazole framework (ZIF-67)-derived Co, N-doped porous carbon on multiwalled carbon nanotubes (MWCNTs), labeled CNTs@Co–N–PC, and investigate its performance as electrocatalysts for the ORR in alkaline medium. This strategy combines pyrolysis with acid etching of ZIF-67 to convert its Co–N4 frames into stable and dense Co, N-doped porous carbon on the surface of MWCNTs. In the core–shell-like CNTs@Co–N–PC hybrid catalysts, the MWCNTs serving as supports effectively inhibit the aggregation of Co–N–PC and therefore guarantee sufficient active sites available for the occurrence of the ORR. Consequently, these CNTs@Co–N–PC electrocatalysts exhibit comparable activity to commercial Pt/C and are featured with favorable long-term durability and superior methanol tolerance.