Temperature-driven growth of uranyl-organic frameworks for efficient photocatalytic CO2 reduction†

The design of efficient photocatalysts to convert CO₂ into CO and other high-value-added chemicals is an effective strategy for solving environmental issues and the energy crisis. Herein, a uranyl-organic framework (UOF) photocatalyst, HNU-94, with uranyl ions as catalytically active centers was designed and prepared by a simple solvothermal method for photocatalytic CO₂ reduction. Particularly, the reaction temperature has an obvious influence on the morphology, which is further reflected in the photocatalytic performance of HNU-94. The morphology of HNU-94 evolves from strip to cluster to flower-like when the temperature rises from 80 °C to 120 °C. The sample obtained at 120 °C can reduce CO₂ to CO under visible light, and the yield reaches 2.57 mmol g⁻¹ after 2 h, which is significantly higher than that of HNU-94 obtained at 80 °C (0.53 mmol g⁻¹). The study demonstrates the efficient photocatalytic activity of uranyl ions for reducing CO₂ and provides an effective method for the logical design of UOF catalysts.