Mandarin Peel Waste-Derived Nitrogen-Doped Porous Carbon Electrocatalysts for Oxygen Reduction Reaction

The development of metal-free, carbon-based electrocatalysts derived from biomass waste has attracted significant attention due to their low cost along with excellent activity, selectivity, and stability for the oxygen reduction reaction (ORR).In this study, a nitrogen (N)-doped porous carbon catalyst was synthesized from mandarin peel waste (MPW) via a simple thermal treatment method.The optimized electrocatalyst, N-doped MPW-derived catalyst-2 (NMPC-2), exhibits a hierarchically porous structure with a high surface area, facilitating efficient access of reactants to active sites.NMPC-2 demonstrates outstanding ORR activity and stability comparable to that of commercial Pt/C, maintaining excellent performance even over 40,000 cycles of accelerated stability testing.Furthermore, its application in a zinc-air battery shows a high peak power density and stable discharge characteristics.This work presents a simple yet effective strategy for developing biowaste-derived ORR electrocatalysts through a sustainable and practical approach.