Ligand Functionalization in Zirconium‐Based Metal‐Organic Frameworks for Enhanced Carbon Dioxide Fixation
Xiaodong Sun, Litong Shi, Haijun Hu, Hongwei Huang, Tianyi Ma
Abstract
Abstract Ligand functionalization has always been considered as an effective method for regulating the catalytic activity of the metal‐organic frameworks (MOFs) materials. Herein, three stable zirconium‐based MOFs (Zr‐MOFs), constructed by the 10‐connected Zr 6 cluster and different groups‐decorated V‐shaped ligands (H 2 L), are successfully synthesized through a facile ligand functionalization method. Subsequently, three isostructural Zr‐MOFs, including the parent structure Zr(H 2 L), amino‐decorated Zr(H 2 L) (NH 2 ‐Zr(H 2 L)), and fluorine and amino bi‐decorated Zr(H 2 L) (F‐NH 2 ‐Zr(H 2 L)), are employed as the platform for systematically investigating the effect of Lewis basic groups on the CO 2 adsorption and separation behavior, more importantly the CO 2 chemical fixation. Benefitting from the decorated Lewis basic groups, not only the CO 2 adsorption enthalpy and selectivity over CH 4 of NH 2 ‐Zr(H 2 L) and F‐NH 2 ‐Zr(H 2 L) are improved, but also their catalytic activities for cycloaddition of CO 2 to form cyclic carbonates are significantly enhanced. Among them, F‐NH 2 ‐Zr(H 2 L) exhibits the most effective performance for cycloaddition of CO 2 and styrene epoxide, which can be attributed to the strong polarization between the CO 2 molecule and the framework of F‐NH 2 ‐Zr(H 2 L). Under a mild condition, the yield of F‐NH 2 ‐Zr(H 2 L) for cycloaddition of CO 2 with styrene epoxide can reach up to 97%, which surpasses most of the reported MOFs‐based catalysts.