A Fully Conjugated Covalent Organic Framework with Oxidative and Reductive Sites for Photocatalytic Carbon Dioxide Reduction with Water

• Published in: Angewandte Chemie International Edition Vol. 62; no. 36; pp. e202308523 - n/a
• Main Authors: Cheng, Yuan‐Zhe, Ji, Wenyan, Hao, Peng‐Yuan, Qi, Xue‐Han, Wu, Xianxin, Dou, Xiao‐Meng, Bian, Xin‐Yue, Jiang, Di, Li, Fa‐Tang, Liu, Xin‐Feng, Yang, Dong‐Hui, Ding, Xuesong, Han, Bao‐Hang
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 04.09.2023
• Edition: International ed. in English
• Subjects: Absorption spectroscopy; Carbon dioxide; Carbon monoxide; Catalysis; Catalysts; Charge transfer; CO2 Reduction; Density functional theory; Electrons; H2O Oxidation; Oxidation; Photocatalysis; Porous materials; Reduction; Rhenium; Ring structures; Separation; Structure-function relationships; Triazine; Vinylene Linkers; Vinylene Linkers; Photocatalysis; CO2 Reduction; H2O Oxidation
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202308523

Constructing a powerful photocatalytic system that can achieve the carbon dioxide (CO2) reduction half‐reaction and the water (H2O) oxidation half‐reaction simultaneously is a very challenging but meaningful task. Herein, a porous material with a crystalline topological network, named viCOF‐bpy‐Re, was rationally synthesized by incorporating rhenium complexes as reductive sites and triazine ring structures as oxidative sites via robust −C=C− bond linkages. The charge‐separation ability of viCOF‐bpy‐Re is promoted by low polarized π‐bridges between rhenium complexes and triazine ring units, and the efficient charge‐separation enables the photogenerated electron–hole pairs, followed by an intramolecular charge‐transfer process, to form photogenerated electrons involved in CO2 reduction and photogenerated holes that participate in H2O oxidation simultaneously. The viCOF‐bpy‐Re shows the highest catalytic photocatalytic carbon monoxide (CO) production rate (190.6 μmol g−1 h−1 with about 100 % selectivity) and oxygen (O2) evolution (90.2 μmol g−1 h−1) among all the porous catalysts in CO2 reduction with H2O as sacrificial agents. Therefore, a powerful photocatalytic system was successfully achieved, and this catalytic system exhibited excellent stability in the catalysis process for 50 hours. The structure–function relationship was confirmed by femtosecond transient absorption spectroscopy and density functional theory calculations. A crystalline network is constructed by incorporating rhenium complexes and triazine ring structures as catalytic sites via robust −C=C− bonding. Appreciable charge‐separation and transfer efficiency drive both the photocatalytic oxidative and reductive reactions in the conversion of CO2 to CO with H2O, and without any additional sacrificial agents or photosensitizers.