Heterophase and Vacancy Engineering of <scp> MoS ₂ </scp> Enables Singlet‐Oxygen‐Dominated Peroxymonosulfate Activation for Durable Fluoroquinolone Degradation

Comprehensive Summary Phase and defect engineering of molybdenum disulfide provides an effective strategy for regulating oxidant activation in heterogeneous advanced oxidation. Herein, a sulfur‐vacancy‐rich 1T/2H‐MoS 2 heterophase catalyst was developed for peroxymonosulfate (PMS) activation and fluoroquinolone degradation. Compared with 1T‐MoS 2 and 2H‐MoS 2 , the 1T/2H‐MoS 2 /PMS system exhibited higher activity, better matrix tolerance, and improved regenerability after ethanol washing. Spectroscopic and quenching analyses revealed that PMS activation proceeds mainly through a non‐radical pathway dominated by singlet oxygen, with a minor contribution from high‐valent molybdenum–oxo species. In situ Raman, EPR, LC‐MS, and frontier‐orbital analysis further suggested a selective degradation route of ofloxacin, initiated by side‐chain oxidation, followed by deeper transformation of the quinolone core. XANES/EXAFS/XPS and DFT calculations showed that the 1T/2H phase boundary and sulfur vacancies cooperatively regulate the local coordination and electronic structure of Mo sites, enabling balanced PMS polarization at interfacial sites while allowing stronger activation at defective motifs. OCTP (organic carbon transfer process) and CRE (catalyst regeneration extent) were further introduced to quantify surface carbon accumulation and catalyst regeneration. This work clarifies how heterophase and vacancy engineering govern selective PMS activation and catalyst durability.