Regulating π‐Conjugation in sp2‐Carbon‐Linked Covalent Organic Frameworks for Efficient Metal‐Free CO2 Photoreduction with H2O

Abstract

AbstractThe development of sp2‐carbon‐linked covalent organic frameworks (sp2c‐COFs) as artificial photocatalysts for solar‐driven conversion of CO2 into chemical feedstock has captured growing attention, but catalytic performance has been significantly limited by their intrinsic organic linkages. Here, a simple, yet efficient approach is reported to improve the CO2 photoreduction on metal‐free sp2c‐COFs by rationally regulating their intrinsic π‐conjugation. The incorporation of ethynyl groups into conjugated skeletons affords a significant improvement in π‐conjugation and facilitates the photogenerated charge separation and transfer, thereby boosting the CO2 photoreduction in a solid‐gas mode with only water vapor and CO2. The resultant CO production rate reaches as high as 382.0 µmol g−1 h−1, ranking at the top among all additive‐free CO2 photoreduction catalysts. The simple modulation approach not only enables to achieve enhanced CO2 reduction performance but also simultaneously gives a rise to extend the understanding of structure‐property relationship and offer new possibilities for the development of new π‐conjugated COF‐based artificial photocatalysts.