Dual‐Path Singlet Oxygen Generation by Sulfur Vacancy Tailored Atomic Iron Assembly for Sustainable Decontamination

Abstract Singlet oxygen ( ¹ O ₂ ) generation via single‐atom catalysis remains challenging in achieving both high efficiency and yield. Herein, S vacancies on MoS ₂ are rationally engineered via a topochemical oxidation strategy, achieving Fe assembly from nanoparticles to nanoclusters and single atoms. Atomic Fe sites situated atop of Mo and isolated S vacancies primarily facilitated the SO ₅ ^•− and O ₂ ^•− pathways, respectively. This dual‐path generation of ¹ O ₂ achieved a high yield (0.36 m m ) with exceptional peroxymonosulfate utilization (73%). Isolated S vacancies allowed universal fabrication of high‐loading SA with stable M−S ₃ coordination (M = Mn, Fe, Co, Ni, and Cu). This unique platform further elucidated modulation of dual‐path ¹ O ₂ generation by the inherent electronic structure of metals, depending on the 3 d orbital unoccupancy, d ‐band center spin, and magnetic moment of metallic SA. The optimized catalyst (Fe _SA ‐MoS _V2 ) demonstrated exceptional performance toward a broad spectrum of contaminant types and wastewater matrices, along with scalable treatment capacity (30 L) and long‐term operation (40 days, equivalent to 960 batch cycles). This study unveils a trade‐off relationship between the topological defective vacancy in structuring metal sites, catalytic activity, and long‐term stability in Fenton‐like catalysis, offering an innovative material design strategy for sustainable wastewater treatment.