Atomically engineered Fe/Mn catalysts enable ultrafast self-sustaining water purification via oxidant-free...

Green Fenton-like reactions based on monometallic single-atom dual-reaction-center systems have emerged as promising strategies for sustainable water purification owing to their oxidant-free operation and low energy demand. However, their practical deployment is often hindered by limited degradation kinetics and unresolved mechanisms. Here, we report a carbon nitride-supported Fe/Mn bimetallic catalyst composed of Fe nanoclusters and adjacent Mn single atoms (FeMn-CN) that enables ultrafast and self-sustaining pollutant degradation under oxidant-free conditions. The catalyst achieves 99.5 % removal of bisphenol A (BPA) within 3 min, setting an ultrahigh rate to date among self-sustaining water purification systems. Combined experimental investigations and density functional theory calculations reveal that the reaction proceeds predominantly via a direct electron-transfer pathway. Fe nanoclusters serve as primary electron acceptors, extracting electrons from BPA without external oxidants, while adjacent Mn single atoms coordinated in Mn-N₄ sites synergistically enhance the electron-accepting capacity of Fe and substantially lower the charge-transfer energy barrier. This atomic-level cooperation endows FeMn-CN with exceptional activity across a broad pH range (pH 2-10), strong tolerance to complex water matrices, high selectivity toward electron-rich contaminants and facile regeneration. Furthermore, continuous-flow reactor tests and life-cycle assessment collectively verify the scalability and superior environmental sustainability of the FeMn-CN process. This work establishes an atomic-level design principle for electron-transfer-dominated self-sustaining remediation materials, advancing the development of next-generation oxidant-free water purification technologies.