Synthesis and CO2 photoreduction of two 3d–4f heterometal–organic frameworks

Abstract

Two 3d–4f heterometal–organic frameworks are synthesized by a steam-assisted conversion method and are characterized by single-crystal X-ray diffraction, PXRD, IR, TG, and UV–vis spectroscopy. Compounds 1 and 2 have similar structures, in which binuclear gadolinium clusters are connected by [M(BPDC)₃] (M = Ni for 1 and Co for 2) secondary building units (SBUs) and extend into 3D frameworks with pcu topologies. In addition, we have also investigated the photoreduction of CO₂ under visible light. The CO yields reached 7622 μmol⁻¹ g⁻¹ and 11 250 μmol⁻¹ g⁻¹ with 1 and 2 as catalysts, respectively, and ruthenium pyridine as the photosensitizer after two hours of visible light irradiation. Both of them have high selectivity values for CO, reaching 94.85% for 1 and 94.46% for 2. Furthermore, the catalytic mechanism is proposed through a photoelectrochemical test. This study provides a feasible strategy for the design of efficient CO₂ photocatalysts with a high charge separation rate.