Light-driven H2O2 production over redox-active imine-linked covalent organic frameworks

Abstract

Imine-linked covalent organic frameworks (COFs) provide distinctive prospects for promoting photocatalytic H₂O₂ production, yet the intricate involvement of imine-derived linkages chemistry under light irradiation remains incompletely elucidated. Here, imine-linked COF-LZU1 demonstrates a visible light-driven H₂O₂ evolution rate of 387 ​μmol ​g⁻¹ ​h⁻¹, particularly, negligible dependence on the sacrificial agents. By virtue of electron paramagnetic spectroscopy and solid-state nuclear magnetic resonance, we experimentally tracked the structure evolution and identified its autooxidation to Wurster's salt mimics under the photocatalytic conditioning. This finding coincides with the radical anion ·O₂⁻ governed reaction pathway and is further rationalized with additional theoretical calculations. This study provides insights into both photophysical/photochemical aspects over the imine-linkage structure.