In situ confinement of CsPbBr3 quantum dots within COFs for enhanced photocatalytic CO2 reduction

Abstract

Confining quantum dots (QDs) within covalent organic frameworks (COFs) has emerged as a promising strategy to address their inherent limitations, particularly the aggregation and environmental instability of perovskite QDs, as well as to enhance charge carrier separation efficiency. In this study, CsPbBr₃ QDs were in situ encapsulated within a TTATFA-COF matrix (TTA = 2,4,6-tris(4-aminophenyl)triazine, TFA = tris(4-formylphenyl)amine), effectively preventing aggregation and environmental degradation, thereby significantly improving their structural and functional stability. The intimate interfacial contact promotes type-II charge transfer, facilitating carrier separation, while the Lewis basic sites within the COF enhance CO₂ adsorption and activation. The resulting CPB@COF-2 composite, containing 19 wt% QDs, achieves a CO production rate of 64.5 μmol g⁻¹ h⁻¹ under visible light with 90.97% selectivity, along with an electron consumption rate of 141.8 μmol g⁻¹ h⁻¹. The material retains over 95% of its initial catalytic activity after 30 hours of continuous operation, demonstrating the dual role of COF confinement in stabilizing perovskite QDs and constructing efficient heterojunctions. This work provides a new design strategy for advanced photocatalytic CO₂ reduction systems.