Xinyao Zhang, Yan She, Xueying Wen, Guixin Hu, Xingpei Yu, Xinyou Li, Xiaoyan Zhu, Ran Niu, Lingling Feng*, Jiang Gong*

Upcycling waste plastic into electrocatalyst: Waste nylon fishnet-derived flexible & rigid Co/Fe-MOF for efficient oxygen evolution reaction

Applied Catalysis B: Environment and Energy (2025) (IF2025 = 21.1)

Oxygen evolution reaction (OER) is a pivotal half-reaction in water electrolysis, yet its sluggish four-electron kinetics and high overpotential remain major obstacles for efficient energy conversion. Addressing these challenges requires electrocatalysts that integrate high activity, structural adaptability, and long-term durability. Herein, we propose a flexible & rigid synergy strategy to construct metal-organic framework (MOF) through converting waste nylon fishnet into cobalt-based MOF (Co-ADP) and further substituting Fe³⁺ to form Co/Fe-ADP. To the best of our knowledge, it is the first work on the upcycling of waste nylon into high value-added MOF. In the Co/Fe-ADP framework, flexible aliphatic linkers derived from nylon impart lattice adaptability, while Fe-O-Co coordination bridges enhance structural rigidity and electronic coupling. As a result, Co/Fe-ADP delivers low overpotential (227?mV at 10?mA?cm^-2), high Faradaic efficiency (97.3%), and long-term stability (over 112?h @ 100 A?cm^-2), ranking as one of the most efficient OER electrocatalysts. Density functional theory calculations reveal that the partial substitution of Co²⁺ by Fe³⁺ upshifts d-band center and enhances the orbital hybridization between Fe 3d and O 2p states. This electronic modulation, coupled with stronger Fe-O covalency and localized charge polarization around the active site, significantly stabilizes the *OOH intermediate and lowers down the energy barrier of the rate-determining step of *O to *OOH from 0.47 to 0.21?eV. This work not only proposes the Waste-to-MOF strategy to upcycle waste nylon, but also introduces a generalizable strategy for engineering flexible & rigid MOF and elucidates the coupled role of ligand dynamics and metal-site coordination environments during OER.