Tailored Persistent Radical‐containing Heterotrimetal‐Organic Framework for Boosting Efficiency of Visible/NIR Light‐driven Photocatalytic CO2 Reduction

• Published in: Advanced functional materials Vol. 33; no. 10
• Main Authors: Hu, Kong‐Qiu, Huang, Zhi‐Wei, Li, Xiao‐Bo, Cheng, Yi, Kong, Xiang‐He, Mei, Lei, Zeng, Li‐Wen, Zhang, Zhi‐Hui, Yu, Ji‐Pan, Gibson, John K., Chai, Zhi‐Fang, Kou, Hui‐Zhong, Shi, Wei‐Qun
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 02.03.2023
• Subjects: Carbon dioxide; CO2; Electromagnetic absorption; Irradiation; Materials science; Metal-organic frameworks; Near infrared radiation; near‐infrared photocatalysts; persistent radical‐containing MOFs; Photoabsorption; Photocatalysis; step‐by‐step synthesis strategy; Topology; Ultraviolet radiation; viologens; visible photocatalysts
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202213039

Promoting light absorption range of photocatalysts is of great significance to improve solar light‐driven photocatalytic CO2 reduction efficiency. Herein, a new viologen‐based multicomponent heterotrimetallic metal–organic framework (MOF) [Cu3Th6(µ3‐O)4(µ3‐OH)4(cpb)12][FeIII(CN)6]6 (IHEP‐14) with an unprecedented (6, 18)‐connected she‐d topology is presented. Upon UV irradiation, this MOF undergoes ligand and iron photoreduction, and a single‐crystal‐to‐single‐crystal transformation to generate persistent radical‐containing MOF [Cu3Th6(µ3‐O)4(µ3‐OH)4(cpb•)12][FeII(CN)6]6 (IHEP‐15). This radical‐containing MOF shows excellent stability without fading after at least 2 months in air. Besides extending the photoabsorption to a wider wavelength range covering from 200 to 2,500 nm, the generation of persistent radical in IHEP‐15 also largely enhances its CO2 adsorption capacity by a factor of three due to the strong affinity between π orbital of the radical and the π system of CO2. These attributes endow IHEP‐15 with excellent visible/NIR light‐driven CO2 photoreduction activity, with CO production rates under visible and NIR irradiation of 570.3 and 209.3 µmol h−1 g−1, respectively. Notably, the latter is a record high for NIR‐induced CO production among all MOFs reported so far. A single‐crystal‐to‐single‐crystal (SCSC) transformation of unprecedented (6, 18)‐connected multicomponent MOF IHEP‐14 generates persistent radical‐containing MOF IHEP‐15, accompanied by a marked increase in CO2 sorption and visible/NIR photocatalytic reduction of CO2 to CO with high selectivity. The NIR light‐driven CO production rate of 209.3 µmol h−1 g−1 for IHEP‐15 is recorded high for NIR‐induced CO production among all MOFs reported so far.