Visible-light reduction CO₂ with dodecahedral zeolitic imidazolate framework ZIF-67 as an efficient co-catalyst

The nanomorphology of ZIFs strongly influences or even improves chemical properties of the metal-organic materials. Nanosized rhombic dodecahedral ZIF-67 crystals were successfully synthesized through a simple co-precipitation method at room temperature, and fully characterized by XRD, FT-IR, DRS, XPS, TEM, SEM, TGA and N₂/CO₂ sorption measurements. The as-prepared ZIF-67 material was applied to be an efficient heterogeneous co-catalyst for the photocatalytic CO₂ reduction by cooperating with a ruthenium-based dye as a photosensitizer under mild reaction conditions. Under the optimal reaction conditions, the photocatalytic CO₂ reduction system achieved a superior catalytic performance with a CO generation rate of 37.4 μmol/30 min, which was much higher than that of other types of MOFs. The carbon source of the evaluated CO was confirmed by ¹³CO₂ isotopic experiment. The stability and reusability of the ZIF-67 co-catalyst in the reaction system were also examined. The present work provides new insights in the developments of nanoscale ZIFs materials for photocatalytic application.