Porphyrin-based Covalent Organic Polymers with Bimetallic Active Sites for Boosting Photocatalytic CO2 Cycloaddition

• Published in: Chemical research in Chinese universities Vol. 41; no. 1; pp. 121 - 130
• Main Authors: Yan, Shengrong, Zhang, Lan, Shi, Songhu, Ren, Yanyan, Liu, Wenhao, Li, Yujie, Duan, Fang, Lu, Shuanglong, Du, Mingliang, Chen, Mingqing
• Format: Journal Article
• Language: English
• Published: Changchun Jilin University and The Editorial Department of Chemical Research in Chinese Universities 01.02.2025; Springer Nature B.V
• Subjects: Analytical Chemistry; Bimetals; Carbon dioxide; Carbonates; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Covalence; Cycloaddition; Electromagnetic absorption; Electron transitions; Electrons; Epichlorohydrin; Inorganic Chemistry; Iron; Lewis acid; Organic Chemistry; Photocatalysis; Photosensitivity; Physical Chemistry; Polymers; Porphyrins; Ring opening; Synergistic effect; Zirconium; Bimetallic active site; Photocatalytic CO; Cyclic carbonate; cycloaddition; Covalent organic polymer
• ISSN: 1005-9040; 2210-3171
• DOI: 10.1007/s40242-025-4202-1

The photocatalytic CO 2 cycloaddition to prepare high value-added chemicals, such as cyclic carbonates (CCs) under mild conditions is an effective strategy to realize carbon neutrality. Herein, through a three-step reaction, the porphyrin-based covalent organic polymer with bimetallic active sites (Fe-COP-Zr) is successfully obtained by coordinating Fe 2+ and Zr 4+ with porphyrin and bipyridine (Bpy), respectively. Owing to excellent photosensitivity of porphyrin moieties, Fe-COP-Zr exhibits outstanding visible light absorption, which is very important for the production of photogenerated carriers. Consequently, Fe-COP-Zr shows high photocatalytic performance towards CO 2 cycloaddition with a yield of 12.1 mmol/h, which is 6 times higher than that of pure covalent organic polymer (COP) and 3 times higher than that of monometallic Fe-COP. The reason for this excellent photocatalytic CO 2 cycloaddition performance may be ascribed to the synergistic effect of Fe and Zr sites. The photogenerated electrons are easily injected into epichlorohydrin (ECH) through Fe—O bonds to form affluent electron transition state, and interact with Zr 4+ as Lewis acid sites for the ring-opening of ECH, which is the rate-determining step for the visible light boosted chemical fixation of CO 2 into CCs. This work might provide some insights for design and preparation of COPs with multiple active sites to modulate their photocatalytic activities.