A solvent-responsive terbium-organic framework for photocatalytic CO2 reduction

Abstract

A Tb-MOF with a 5,5,6-c 3-nodal net, {[Tb(DTDA)_1.5·2H₂O]·DMF·8H₂O}_n (AQNU-4), has been synthesized (DTDA = 2′,5′-diethoxy-[1,1′:4′,1′′-terphenyl]-4,4′′-dicarboxylic acid). AQNU-4 contains a 1-periodic secondary building unit (rod SBU) and has an unusual topological type with the point symbol {3²·4⁴·6²·7·8}{3²·4⁶·5·6}{3²·4⁶·5²·6⁵}. Efficient light harvesting and electron−hole separation make AQNU-4 an effective photocatalyst for use in the CO₂ reduction reaction (CO₂RR). Interestingly, as a photocatalyst, AQNU-4 shows an obvious solvent dependence during the catalytic process. In cyclohexanone in particular, it shows the highest CO₂ to CO conversion, reaching 138.65 μmol g⁻¹ h⁻¹, making AQNU-4 a good solvent-responsive MOF material.