Pair‐Resolved Fe–M Dual‐Atom Catalysts for Programmed PMS Activation: Mechanisms, Membrane Confinement, and Standardized Benchmarks

Abstract Fe‐based dual‐atom catalysts (Fe–M DACs) are redefining peroxymonosulfate (PMS) activation by enabling programmable switching between radical and non‐radical routes. This Review synthesizes recent progress through a pair‐resolved lens (Fe–Co, Fe–Mo, Fe–Fe, Fe–Ni), linking µ‐peroxo bridging and spin/electronic coupling to pathway selection, pollutant selectivity, and stability. A co‐selection matrix distinguishes literature testing preferences from true performance correlations, while a BPA case study maps metal‐dependent route bifurcation (phenoxy‐radical/interfacial electron‐transfer (ETP) versus hydroxylation‐opening‐mineralization). Translation to practice is highlighted by membrane‐confined systems that couple reaction and separation, maintain flux in saline/organic‐rich effluents, and lower toxicity, supported by QSAR predictions and bioassays. Design rules are distilled for antibiotics and other electron‐rich targets, and outline standards for reporting conditions, metal leaching, TOC mineralization, and evidence matrices (EPR, isotope/quenching, operando XAS/Raman, DFT). Finally, opportunities are charted for tailored strategies toward halogenated/strongly electron‐deficient pollutants and emerging contaminants (PFAS, ARGs, microplastics). Collectively, Fe–M DACs establish an atom‐level “catalyst–co–catalyst” paradigm for robust, selective, and safer advanced oxidation in complex waters.