Synergistic effect of dual sites on bimetal-organic frameworks for highly efficient peroxide activation

Active site engineering is of significant importance for developing high activity metal-organic frameworks (MOFs) for catalytic applications. Herein, we develop a one-pot strategy to construct bimetal organic frameworks with Fe-Co dual sites for Fenton-like catalysis. Density functional theory (DFT) demonstrated that the introducing Co heteroatoms into MIL-101(Fe) (MIL represents Matérial Institute Lavoisier) was favorable for the formation of electron-deficient centers around benzene rings and electron-rich centers around Fe/Co. This synergistic effect could effectively decrease the energy barrier of H₂O₂ activation. Due to the facilitated charge transfer in the coordinated structures, MIL-101(Fe,Co) with engineered dual sites exhibited exceptionally high efficiency for the degradation of ciprofloxacin (CIP). The reaction rate of MIL-101(Fe,Co)/H₂O₂ system was 0.12 min⁻¹, which was nearly 7.5 times higher than that of pristine MIL-101(Fe). The reaction mechanism of heterogeneous Fenton-like catalysis was fundamentally investigated by series of in-situ techniques, such as DRIFTS and Raman. ·OH radicals generated by H₂O₂ activation endowed the inspiring ability of MIL-101(Fe,Co) for water decontamination. This work offers a facile principle of exploring MOFs-based Fenton-like catalysts with a wide working pH range for environmental applications.