Coupling doped halogen sites in copper(i)–organic frameworks with cuprous oxide for high selectivity CO2 photoreduction with H2O

Abstract

Photoreduction catalysis offers an eco-friendly approach to convert CO₂ into valuable chemicals. However, understanding the influence of halide active sites in metal–organic framework (MOF) catalysts on photoreduction and selectivity remains limited. We report different halogen (X) sites (X = Cl, Br and I) in copper(I)–organic frameworks (CuX–bpy) grown on Cu₂O for photoreduction of CO₂ without the assistance of additional sacrificial agents and photosensitizers. Impressively, the Cu₂O@CuCl–bpy-MOF efficiently photo-reduces CO₂ into formate with a high yield of 1520 μmol g⁻¹ after 12 hours of reaction. Density functional theory calculation results reveal that the effective coordination coupling between the MOF and semiconductor facilitates rapid electron transfer leading to efficient CO₂ reduction and H₂O oxidation.