Highly Stable Lanthanide-Organic Frameworks Based on {Ln6O8} Clusters with Photocatalytic Reduction of CO2to CO

Metal–organic frameworks (MOFs) with adjustable structures, diverse chemical functionalities, and excellent CO2capture ability have shown important potential application in the photocatalytic reduction of CO2to valuable fuel to curb the energy crisis. In this work, a series of new isostructural lanthanide-organic frameworks based on hexanuclear {Ln6O8} clusters, {(DMA)2[Ln6(μ3–OH)8(H2O)6(SBTC)3]}n(Ln-MOFs, Ln = Eu, Dy, Gd, Tb, Yb; H4SBTC = 5,5′-(ethene-1,2-diyl) di-isophthalic acid; DMA = dimethylamine cation) were synthesized by the solvothermal method. Ln-MOFs were metal–organic frameworks formed by {Ln6(μ3–OH)8} clusters and poly(carboxylic acid) ligands H4SBTC, which exhibited excellent photocatalytic properties for the reduction of CO2to CO. Among these Ln-MOFs, the production rate of photocatalytic reduction of CO2to CO by Eu-MOFwas 663.00 μmol·h–1·g–1and the selectivity reached 94.2%, utilizing [Ru(bpy)3]Cl2·6H2O as photosensitizers. Experimental characterizations and density functional theory (DFT) calculations unveiled that the effective charge separation, strong CO2binding affinity, weak H2O adsorption energy, as well as low reaction energy barriers for the *COOH intermediates over Eu-MOFplay an important role in possessing superior photoactivity. This study provides insights into the field of Ln-MOF materials for efficient photocatalytic CO2reduction and conversion applications.