Isomerism-triggered spin-state modulation orchestrates a photo-self-Fenton assembly line for micropollutant...

Photo-self-Fenton oxidation represents a promising strategy for the degradation of emerging organic contaminants. However, constructing systems that integrate efficient in situ H₂O₂ production with immediate H₂O₂ activation while maintaining precise kinetic coupling remains a critical challenge. Herein, a spin-electronic regulation strategy is established, in which the local coordination microenvironment and electronic structure of Mn single-atom centers are precisely tailored via isomerized modulation of the COF skeleton, thereby enhancing deep pollutant mineralization. ZFC and FC magnetization measurements, together with DFT calculations, demonstrate that the COF skeleton drives H₂O₂ generation via O₂ reduction, while COF-skeleton isomerization precisely regulates the spin-state of Mn centers. The high-spin Mn centers in Mn/COF-H lower the energy barrier for H₂O₂ activation and accelerate •OH generation. Notably, Mn/COF-H exhibits a CBZ degradation rate constant of 0.059 min^-1, which is approximately 9.83-fold and 14.75-fold greater than those of Mn/COF-L and Mn/COF-M, respectively. LC-MS and TOC analysis further reveals that Mn/COF-H not only facilitates stepwise oxidative cleavage of pollutant molecules but also enhances deep mineralization. Overall, this study establishes a dynamic photo-self-Fenton assembly line that couples in situ generation, immediate activation, and sustained oxidation, opening a new spin-electronic regulation pathway for the development of efficient, low-energy advanced oxidation systems.