Zn2+-Coordinated Ionic Covalent Organic Frameworks for Photocatalytic H2O2 Generation and Inactivation of Clinical Isolates

Hydrogen peroxide (H 2 O 2 ) serves as both a versatile green oxidant and critical precursor for reactive oxygen species (ROS), with broad applications spanning environmental remediation to biomedical therapies. However, sustainable H 2 O 2 production remains challenging due to limitations in conventional photocatalysts, such as restricted visible-light response and inefficient charge separation. In this work, we developed a novel zinc-functionalized ionic covalent organic framework (iCOF) through strategic metal coordination. By anchoring Zn 2+ ions to pyridinic nitrogen sites within a bipyridine-triaminoguanidine framework (BDTD), the resulting Zn-BDTD material maintained structural crystallinity-unachievable with Pt, Pd, or Ag analogues-while significantly enhancing visible-light harvesting, charge transport, and oxygen adsorption. This engineered material achieves a photocatalytic H 2 O 2 synthesis rate at 1522.6 μmol·g -1 ·h -1 under the visible light (λ > 420   nm), representing the 31% increase over pristine BDTD (1160.9 μmol·g -1 ·h -1 ) with a 3.47% apparent quantum yield at 420   nm. In addition, its potent antibacterial activity achieving >99% inactivation of clinical isolates ( Staphylococcus aureus, Pseudomonas aeruginosa ) at 10   μg/mL under visible light irradiation. Mechanistic studies reveal a synergistic dual-pathway H 2 O 2 generation mechanism, combining dominant 2e - oxygen reduction (stabilized by Zn-coordinated superoxide radicals) with auxiliary 2e - water oxidation. Density functional theory calculations confirm Zn coordination drastically reduces the energy barrier for O 2 adsorption (ΔG = −1.39   eV vs. +1.19   eV for BDTD). This work establishes metal-coordinated iCOFs as a versatile platform for integrated chemical synthesis and antimicrobial applications, particularly against clinical isolates.