A Cu^I Cluster-Based Covalent Metal-Organic Framework as a Photocatalyst for Efficient Visible-Light-Driven Reduction...

The application of solar energy to convert CO₂ into high-value chemicals and fuels has been considered a highly desirable approach to relieving the greenhouse effect and energy crisis. However, the exploration of appropriate photocatalysts remains a major challenge. Combining the respective advantages of covalent organic frameworks and metal-organic frameworks to construct covalent metal-organic frameworks (CMOFs) can be a valid strategy to provide efficient, reliable, and eco-friendly photocatalysts. In this study, a Cu^I cluster-based CMOF (JNM-2) is used as a photocatalyst for CO₂ photoreduction under visible-light irradiation. JNM-2 exhibits remarkable efficiency in photocatalytic CO₂ reduction with high production rates of HCOOH (9019 μmol g^-1  h^-1 ) and CO (835 μmol g^-1  h^-1 ). The active center, reaction intermediates, and product generation pathways are elucidated by in situ DRIFTS and DFT calculations. This work demonstrates the tremendous possibilities of CMOFs as photocatalysts for CO₂ reduction and provides profound insights into the mechanism of CO₂ conversion into HCOOH/CO by using a molecularly accurate structural model.