Hollow Zn−Co Based Zeolitic Imidazole Framework as a Robust Heterogeneous Catalyst for Enhanced CO2 Chemical Fixation

• Published in: Chemistry, an Asian journal an Asian journal, 2019-12, Vol.14 (23), p.4375-4382
• Main Authors: Tang, Bo, Li, Shuang, Song, Wei‐Chao, Li, Yan, Yang, En‐Cui, Zhao, Xiao‐Jun, Li, Landong
• Format: Article
• Language: English
• Subjects: Antifungal agents; Bimetals; Carbon dioxide; Carbonates; Catalytic activity; Chemical etching; Chemistry; CO2 conversion; Cobalt; cyclic carbonates; Cycloaddition; Electron microscopy; Fine chemicals; hollow structure; Imidazole; Mass transfer; Microscopy; Organic chemistry; post-synthesis; Recyclability; Tannic acid; zeolitic imidazole framework; Zinc
• ISSN: 1861-4728; 1861-471X
• DOI: 10.1002/asia.201901246

The efficient chemical conversion of carbon dioxide (CO2) into value‐added fine chemicals is an intriguing but challenging route in sustainable chemistry. Herein, a hollow‐structured bimetallic zeolitic imidazole framework composed of Zn and Co as metal centers (H‐ZnCo‐ZIF) has been successfully prepared via a post‐synthetic strategy based on controllable chemical‐etching of the preformed solid ZnCo‐ZIF in tannic acid. The creation of hollow cavities inside each monocrystalline ZIFs could be achieved without destroying the intrinsic frameworks, as characterized by field‐emission scanning electron microscopy, transmission electron microscopy, and X‐ray diffraction technologies. The as‐synthesized H‐ZnCo‐ZIF exhibited remarkable catalytic activity in the cycloaddition of CO2 with epoxides to the corresponding cyclic carbonates, outperforming the solid ZnCo‐ZIF analogue due to the improved mass transfer originating from the hollow structure. More importantly, due to stabilization of metal centers in the ZIF framework by the tannic acid shell, H‐ZnCo‐ZIF exhibited good recyclability, and no activity loss could be observed in six runs. The present study provides a simple and effective strategy to enhance the catalytic performance of ZIFs by creating a hollow structure via chemical etching. Sleepy Hollow: A hollow‐structured Zn−Co based zeolitic imidazole framework, obtained from post‐synthesis chemical etching, serves as a robust heterogeneous catalyst for the cycloaddition of CO2 with epoxides to yield the corresponding cyclic carbonates.