Tailoring Interfacial Active Sites and Valence States via Ligand Modulation in ZIF-Derived Catalysts for Enhanced Fenton-like Reactions

Zeolitic imidazolate framework (ZIF)-derived catalysts have emerged as promising materials for Fenton-like advanced oxidation processes aimed at the degradation of persistent organic pollutants. However, the impact of the ligand chemistry on the interfacial properties and catalytic performance of these materials remains underexplored. Herein, Fe-doped ZIF precursors (ZIF-7/8/90) with different imidazolate ligands were pyrolyzed to obtain corresponding carbon-supported catalysts (ZIF-7/8/90-Fe-900) and evaluated under environmentally relevant water treatment conditions. Despite their similar structures, ZIF-90-Fe-900 exhibited superior performance in activating peroxymonosulfate for the degradation of various pollutants, achieving a considerably higher reaction rate constant compared with ZIF-7-Fe-900 and ZIF-8-Fe-900. The removal efficiency of total organic carbon followed a similar trend, and common environmental anions had minimal impact on the catalytic performance, highlighting its robustness under real-world water treatment conditions. The enhanced catalytic efficiency of ZIF-90-Fe-900 is attributed to ligand-directed interfacial engineering, where the oxygen-rich ligand promotes a higher Fe loading and a favorable Fe valence state distribution. These features improve peroxymonosulfate uptake and enhance the production of singlet oxygen and electron transfer. This work highlights the critical role of organic ligand chemistry in tuning interfacial structure and function, offering valuable design principles for the development of high-performance ZIF-derived Fenton-like catalysts for environmental remediation.