Macrocycle-on-COF photocatalyst constructed by in-situ linker exchange for efficient photocatalytic CO2 cycloaddition

Functionalizing macrocycle with gas capture and catalytic ability onto covalent organic frameworks (COFs) can generate hierarchical porous materials with enhanced properties, while the challenge is how to improve full utilization of the active sites and maintain the crystallinity of the parent framework. Herein, we developed a "Macrocycle-on-COF" strategy by partial in-situ linker exchange to gain core-shell hybrids containing hierarchical pores. We demonstrated that the macrocycle-on-COF with functionalized pillar[5]arene have a profound effect on highly CO2 adsorption and abundant active sites. The photoelectrical measurement showed that the macrocycle-on-COF was an excellent photocatalyst with fast photoresponse and superior charge separation efficiency. With the assistance of light, the functionalized OH-P[5]-on-COF achieves efficient photocatalytic CO2 cycloaddition reaction under ambient conditions (20 °C and 1 atm), in which a 99% conversion can be achieved within 3 h and the performance is superior compared to previously reported COFs. This study presents the first example of using COFs as photocatalysts for photocatalytic CO2 cycloaddition reaction under ambient conditions.