Porphyrin-based conjugated organic polymer with dual metal sites for highly active and selective visible-light-driven reduction of CO2 to CO

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 51; no. 39; pp. 15022 - 15030
• Main Authors: Li, Jinyu, Hou, Yuxia, Cheng-Xing, Cui, Zhang, Xiupeng, Ji-Chao, Wang, Wang, Airong, Chen, Zhipeng, Li, Mingchang, Tianjun Lou
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 11.10.2022
• Subjects: Carbon dioxide; Carbon monoxide; Catalytic activity; Chemical reduction; Cobalt; Copper; Light irradiation; Photocatalysis; Polymers; Porphyrins; Reagents
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d2dt02500k

A porphyrin-based conjugated organic polymer (COP) was constructed from 5,10,15,20-tetrakis(4-bromophenyl)porphyrin copper (CuTBPP) and 5,5′-bis-ethynyl-2,2′-bipyridine (BPY) via Sonogashira coupling. Its complex Co/CuTBPP–BPY–COP (with dual metal sites composed of copper porphyrin and a cobalt BPY unit) was prepared by coordination with Co2+. All of the prepared CuTBPP–BPY–COP and Co/CuTBPP–BPY–COP compounds exhibited excellent photocatalytic performance toward CO2 reduction under visible-light irradiation without another sacrificial reagent but only H2O. Co/CuTBPP–BPY–COP (dual metal sites) exhibited better photocatalytic activity than CuTBPP–BPY–COP (a single metal site). Co/CuTBPP–BPY–COP retained a higher photocatalysis capacity for CO2 reduction after 10 consecutive cycles. The total quantity of CO product was 263.2 μmol g−1 after 10 h of irradiation. Theoretical studies indicate that introducing Co metal centers and nitro groups are more favorable for the photoreduction catalysis of CO2 compared with that using CuTBPP–BPY–COP.