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

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-N-4 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.