Immobilization of iron phthalocyanine on MOF-derived N-doped carbon for promoting oxygen reduction in zinc-air battery

One type of MOF-derived porous N-doped carbon anchoring iron phthalocyanines has been obtained. Owing to abundant Fe-N4 active centers, FePc@NC-1000 exhibits excellent ORR activity, and its assembled zinc-air batteries also show favorable performance and durability. [Display omitted] •One Zn-based pillar-layer MOF nanosheet is easily achieved by its restricted axial growth.•Iron phthalocyanines could be firmly immobilized into MOF-derived porous Ndoped carbons.•The optimal catalyst of FePc@NC-1000 shows high oxygen reduction activity and durability. Functional carbon nanomaterials play a crucial role in the cathodic oxygen reduction reaction (ORR) for sustainable fuel cells and metal-air batteries. In this study, we propose an effective approach to immobilize iron phthalocyanines (FePc) by employing a porous N-doped carbon material, denoted as NC-1000, derived from a sheet-shaped coordination polymer. The resulting NC-1000 possesses substantial porosity and abundant pore defects. The nitrogen sites within NC-1000 not only facilitate FePc adsorption but also optimize the electron distribution at the Fe-N site. The FePc@NC-1000 composite material exhibits a significant number of active centers in the form of Fe-N4 moieties, showcasing satisfactory ORR activity. Specifically, it demonstrates an onset potential of 0.99 V, a positive half-wave potential of 0.86 V, a large limiting current of 5.96 mA cm−2, and a small Tafel slope of 44.41 mV dec-1. Additionally, theoretical calculations and experimental results confirm the favorable performance and durability of zinc-air batteries assembled using FePc@NC-1000, thereby highlighting their considerable potential for practical applications. Overall, this study provides a comprehensive exploration of the enhanced catalytic performance and increased stability of metal–organic framework-derived functional carbon nanomaterials as cost-effective, efficient, and stable catalysts for the ORR.