Photo-generated dinuclear {Eu(II)}2 active sites for selective CO2 reduction in a photosensitizing metal-organic framework

Photocatalytic reduction of CO 2 is a promising approach to achieve solar-to-chemical energy conversion. However, traditional catalysts usually suffer from low efficiency, poor stability, and selectivity. Here we demonstrate that a large porous and stable metal-organic framework featuring dinuclear Eu(III) 2 clusters as connecting nodes and Ru(phen) 3 -derived ligands as linkers is constructed to catalyze visible-light-driven CO 2 reduction. Photo-excitation of the metalloligands initiates electron injection into the nodes to generate dinuclear {Eu(II)} 2 active sites, which can selectively reduce CO 2 to formate in a two-electron process with a remarkable rate of 321.9 μmol h −1 mmol MOF −1 . The electron transfer from Ru metalloligands to Eu(III) 2 catalytic centers are studied via transient absorption and theoretical calculations, shedding light on the photocatalytic mechanism. This work highlights opportunities in photo-generation of highly active lanthanide clusters stabilized in MOFs, which not only enables efficient photocatalysis but also facilitates mechanistic investigation of photo-driven charge separation processes.