Synergy between microelectrolysis and trimetallic MOFs activates perovskite monosulfate for ofloxacin degradation†

Based on the carbonization of metal–organic frameworks, this study developed and synthesized a catalyst, referred to as tri-metallic MOF carbonization (TMC), that enhanced electron transfer to facilitate the generation of singlet oxygen. For 20 mg L⁻¹ OFX, micro-electrolysis of PMS in the presence of the TMC catalyst demonstrated remarkable degradation efficiency, attaining 90% degradation in 20 minutes, with a reaction rate constant of 0.18 min⁻¹. The system was catalytically active and capable of degrading different types of pollutants with high efficiency over a wide pH range. The doping of Co/Cu metals promoted the production of ¹O₂ and high-valent metals, leading to a charge transfer between different metals (Cu → Co, Cu → Fe). The oxidation of TMC by PMS led to the hetero-cleavage of the O–O bond and produced high-valent metal–oxygen. CoFe₂O₄ and CuFe₂O₄ with spinel crystal structures were observed to exhibit increased content of Co(II) and Cu(II), respectively. Co(II) was found to be used as an active site for activation of PMS to produce ¹O₂, and Cu(II) facilitated the non-radical pathway of the reaction. Fe(II) generated by high-valent metals via PMS and the oxidative degradation of electron-rich pollutants. Therefore, high-valent metals and ¹O₂ play crucial roles in the activation mechanism of perovskite monosulfate (PMS).