Incorporating Fe-O cluster in multivariate (MTV) metal–organic frameworks for promoting visible-light photo-Fenton degradation of micropollutants from water

Exploring efficient heterogeneous photo-Fenton catalysis is crucial for advanced water purification. In this study, a series of multivariate (MTV) metal–organic framework MIL-100 (Sc _{0.98, 0.95, 0.87, 0.75, 0.58}, Fe _{0.02, 0.05, 0.13, 0.25 0.42}) catalysts with increasing Fe contents were synthesized to effectively degrade micropollutants. By incorporating the Fe-O cluster into the framework, the degradation rate of sulfamethylthiazole (SMX) was improved 11.85 times over the MTV MIL-100 (Sc _0.58, Fe _0.42). The permanent porous structures and high surface areas (1597 m²/g ∼ 1389 m²/g) facilitated the adsorption processes. Results show that the initial adsorption rates for quinolone and anti-inflammatory groups were extremely high, with v₀ = 463.16 ∼ 407.15 μg/g min. The modified material enhanced the visible-light absorption and facilitated the formation of reactive oxygen species (•OH, ¹O₂, and O₂^•−) under the irradiation of solar light. Electron paramagnetic resonance trapping technologies and quenching experiments were applied. The pathway for ROS formation under solar-light irradiation was proposed in detail. Aromatic intermediates were identified and quantitatively analyzed using UPLC-Q-TOF-MS. We believe that this strategy of incorporating mixed metal clusters in MOFs offers useful guidance to improve the performance of current materials.