Structure regulation and catalytic performance of amine-functionalized zeolitic imidazolate frameworks for CO2 cycloaddition
Meng Linghu, Yang Jiakun, Huo Zichen, Qin Wu, Yaoyuan Zhang, Shi Daxin, Chen Kangcheng, Liu Helei, Xu Xiyan, Hansheng Li, Hang Xu
Abstract
The capture and transformation of CO 2 , utilized as a C1 resource, play an integral role in mitigating CO 2 emissions and addressing the emerging 'carbon source crisis.' The CO 2 cycloaddition to cyclic carbonate is particularly noteworthy. A critical factor in optimizing the efficiency and minimizing the costs associated with CO 2 cycloaddition is the selection of an effective catalyst. A novel amine-functionalized intramolecular acid-base synergistic ZIF catalyst, designated as ABF-ZIF-X, was synthesized using a mixed ligand method, employing 2-MeIM and the larger molecular-sized ligand 2-amBzIM. The introduction of an amino active center and the strategic regulation of the active site defects in metal ions enable ABF-ZIF-X to enhance the density of Lewis acid and base sites. This enhancement facilitates intramolecular acid-base cooperation, which is pivotal for effective CO 2 cycloaddition catalysis. Notably, ABF-ZIF-X exhibits exceptional catalytic activity in the cycloaddition of EBH with CO 2 , eliminating the need for additional solvents and co-catalysts. The reaction mechanism of CO 2 cycloaddition, which is intramolecular acid-base synergistic catalysis and bimolecular activation, was proposed. Among the synthesized catalysts. ABF-ZIF-0.15 shows superior performance, achieving an impressive 96.7% conversion of EBH and a selectivity of 97.1%. Furthermore, this catalyst demonstrates remarkable reusability, maintaining high activity across five cycles.