Cobalt-Modification on UiO-bpydc MOF Facilitates Ligand-to-Metal Charge Transfer for Superior Visible-Light Photocatalytic Degradation of Refractory Fluoroquinolone Antibiotics

Pollutant removal through green photocatalysis combined with advanced oxidation processes (AOPs) is critical for efficient wastewater treatment but is limited by poor light harvesting and inefficient oxidant activation. This study addresses these challenges through developing a Co-incorporated UiO-bpydc MOF for enhanced visible-light-driven photocatalysis via peroxymonosulfate (PMS) bridged ligand-to-metal charge transfer (LMCT). The MOF was synthesized through direct cobalt complexation into the UiO-bpydc framework for enabling visible light absorption. The UiO-bpydc(Co) achieved 95.8% degradation of lomefloxacin (LOM) within 30 minutes in the presence of PMS, attributing to narrowed bandgap (i.e., 2.82 eV), improved charge transfer via Co centers, and increased pollutant affinity due to electron-rich ligand. Additionally, the generation of long-lifespan singlet oxygen ( 1 O 2 , 41.8%) was identified as the key reactive species. Theoretical calculations indicated a reduced HOMO-LUMO gap upon the formation of a -Co-OOSO 3 bridge, which promotes carrier separation and improves pollutant-catalyst interactions. The degradation pathways and toxicity evolution of intermediates were clarified, while the exceptional stability, recyclability, and broad pollutant applicability of UiO-bpydc(Co) demonstrate its potential for utilization in oxidative environments This work highlights the potential of transition metal doping to alter the electronic structure of MOFs for target-specific catalytic reactions, offering new opportunities for advanced environmental remediation technologies.