Biomimetic Interface with Dynamic Disulfide Bonds Boosts Durable Photoconversion of Diluted CO2.

Abstract

The integration of molecular catalysts into covalent organic frameworks (COFs) provides a promising route for solar-driven conversion of low-concentration CO2 into value-added fuels and chemicals. However, the intrinsic rigidity of conventional COFs greatly impedes the adaptive incorporation of molecular catalysts and disrupts directional charge migration, which inevitably limits their photocatalytic activity and operational durability under dilute CO2 conditions. Herein, we report a biomimetic strategy of incorporating dynamic disulfide bonds into COFs for enabling adaptive anchoring of [Co(bpy)3]2+ (bpy = 2,2'-bipyridine) and promoting interfacial electronic coherence to significantly improve CO2 photocatalytic efficiency and stability. The resulting disulfide-rich TFBP-APDS COFs achieve a CO evolution rate of 10.6 mmol g-1 h-1 with a high selectivity of 94.5%, which is 2.4 times higher than its disulfide-free analogue TFBP-BD (4.4 mmol g-1 h-1; 78.9% selectivity). Combined spectroscopic and theoretical analyses reveal that the dynamic disulfide linkages enhance adaptive Co-S interaction with [Co(bpy)3]2+ and strengthen interfacial electronic coupling, thereby facilitating efficient and directional charge transfer across the COF framework. In a homemade integrated flow-type photocatalytic microreactor, TFBP-APDS achieves a CO production rate of 5.1 mmol g-1 h-1 under simulated flue gas conditions (15% CO2) and maintains operation for 300 h without performance loss.