Two-Dimensional Conjugated Metal-Organic Frameworks for Photochemical Transformations

Photochemical transformation represents an attractive pathway for the conversion of earth-abundant resources, such as H₂O, CO₂, O₂, and N₂, into valuable chemicals by utilizing sunlight as an energy source. Recently, two-dimensional conjugated metal-organic frameworks (2D c-MOFs) have emerged as the focal points in the field of photo-to-chemical conversion due to their advantages in light harvesting, electrical conductivity, mass transport, tunable electronic and porous structures, as well as abundant active sites. In this review, we highlight various physical and chemical features of 2D c-MOFs that can contribute to enhanced photo-induced exciton generation, charge transport, proton migration and redox catalysis. Then, the existing strategies to integrate suitable light absorbers and/or co-catalysts onto 2D c-MOFs for photochemical transformations (with a particular focus on H₂ evolution, CO₂ reduction and O₂ reduction) have been discussed. Finally, the challenges and opportunities of using 2D c-MOFs in other photochemical applications (e.g., N₂ fixation, organic synthesis, and environmental remediation) are assessed.