Fibrous Pb(II)-Based Coordination Polymer Operable as a Photocatalyst and Electrocatalyst for High-Rate, Selective CO2-to-Formate Conversion

Chomponoot Suppaso, Ryosuke Nakazato, Shoko Nakahata, Yoshinobu Kamakura, Fumitaka Ishiwari, Akinori Saeki, Daisuke Tanaka, Kazuhide Kamiya,* Kazuhiko Maeda*

A nonporous [Pb(tadt)]n (tadt = 1,3,4-thiadiazole-2,5-dithiolate) coordination polymer, KGF-9, with a 2D infinite (−Pb−S−)n structure has been previously reported as a precious-metal-free photocatalyst for selective CO2-to-formate conversion under visible light. In the present work, a microwave (MW)-assisted solvothermal reaction is used to synthesize KGF-9 with improved physicochemical properties and catalytic activity. Compared with KGF-9 prepared by the previously reported methods, that prepared by the new synthesis route exhibited a greater specific surface area, greater crystallinity, and greater photoconductivity. These improved properties led to a drastic increase of the apparent quantum yield (AQY) for selective formate production, from 2.6 to 25% at 400 nm; this AQY represents a record-high value among reported heterogeneous photocatalysts for CO2-to-formate conversion. Interestingly, the AQY for formate production is unchanged irrespective of the light intensity (0.04–14 mW cm−2), indicating little contribution of charge accumulation in the bulk during the reaction (i.e., indicating efficient charge transport to surface reactants). When composited with Ketjen Black, KGF-9 enabled the electrochemical conversion of CO2 to formate in aqueous solution while maintaining a high selectivity. A high-rate reduction of CO2 to formate with a total absolute current density of 200–300 mA cm−2 is achieved, with a Faradaic efficiency (FE) of >90%.

Adv. Funct. Mater. 2024, in press.
論文: https://onlinelibrary.wiley.com/doi/10.1002/adfm.202417223