Confining charge-transfer complex in a metal-organic framework for photocatalytic CO2 reduction in water

• Published in: Nature communications 2023-07, Vol.14 (1), p.4508-4508, Article 4508
• Main Authors: Karmakar, Sanchita, Barman, Soumitra, Rahimi, Faruk Ahamed, Rambabu, Darsi, Nath, Sukhendu, Maji, Tapas Kumar
• Format: Article
• Language: English
• Subjects: 119/118; 140/131; 147/135; 147/143; 639/638/298/921; 639/638/440/947; 639/638/77/887; 639/638/77/890; Absorption spectroscopy; Aqueous solutions; Carbon dioxide; Charge transfer; Chemical reduction; Confined spaces; Conversion; Density functional theory; Electron paramagnetic resonance; Electron spin resonance; Electron transfer; Energy consumption; Fuel production; Humanities and Social Sciences; Irradiation; Kinetics; Light; Light irradiation; Metal-organic frameworks; Methane; Methyl viologen; Morphology; multidisciplinary; Photocatalysis; Pore size; Renewable fuels; Science; Science (multidisciplinary); Zirconium
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-40117-z

In the quest for renewable fuel production, the selective conversion of CO 2 to CH 4 under visible light in water is a leading-edge challenge considering the involvement of kinetically sluggish multiple elementary steps. Herein, 1-pyrenebutyric acid is post-synthetically grafted in a defect-engineered Zr-based metal organic framework by replacing exchangeable formate. Then, methyl viologen is incorporated in the confined space of post-modified MOF to achieve donor-acceptor complex, which acts as an antenna to harvest visible light, and regulates electron transfer to the catalytic center (Zr-oxo cluster) to enable visible-light-driven CO 2 reduction reaction. The proximal presence of the charge transfer complex enhances charge transfer kinetics as realized from transient absorption spectroscopy, and the facile electron transfer helps to produce CH 4 from CO 2 . The reported material produces 7.3 mmol g −1 of CH 4 under light irradiation in aqueous medium using sacrificial agents. Mechanistic information gleans from electron paramagnetic resonance, in situ diffuse reflectance FT-IR and density functional theory calculation. Maji and coworkers report the selective conversion of CO 2 to CH 4 under visible light by utilizing a charge transfer complex within Zr-MOF-808 pores. The complex ultimately facilitates efficient multielectron reduction at the Zr-catalytic center.