Upcycling IndustrialResin to Transition Metal-ModulatedN‑Doped Carbon Electrocatalysts for Durable Oxygen EvolutionReaction

For rational electrocatalyst design toward efficiency and durability, supports with high conductivity and well-defined structures that can host active sites firmly are highly demanded. In this study, we report a scalable approach to synthesize nitrogen-doped carbon-based (NC) electrocatalysts modulated with transition metals (Ni, Fe, Co, and NiFe) from cheap industrial ion-exchange resins. The rigid nitrogen-rich, uniform composition of the resin leads to a porous NC framework that can host metal sites with optimized mass transfer via the pores. Ni@NC, Fe@NC, and Co@NC demonstrate comparable OER activity, and an optimized metal loading is suggested, achieving the balance between site efficiency and total site number (e.g., 2 wt % for Ni@NC). Further tuning of the metallic composition produced NiFe@NC with improved activity and remarkable stability during 100 h of electrolysis, benefiting from enhanced nanoparticle dispersion and structural integrity. This work provides a sustainable and cost-effective solution for electrocatalyst design by valorizing industrial resin, advancing environmental sustainability, and developing high-performance materials for renewable energy technologies.