Porphyrin-Based Metal-Organic Framework Photocatalysts: Structure, Mechanism and Applications

In recent years, porphyrins have been frequently reported as photocatalysts due to their fascinating photochemical properties. However, porphyrins have the same shortcomings as other homogeneous photocatalysts, such as poor stability and difficulty in recovering. To solve this problem, it is a good strategy to form a porphyrin-based metal-organic framework (PMOF) by modifying porphyrin functional groups and adding metals as nodes to connect and control the arrangement of porphyrins. The metal nodes control the rigidity and connectivity of the porphyrin modules to order them in the MOF, which improves the stability of the porphyrins, avoids porphyrin aggregation and folding, and increases the active sites for photocatalytic reactions. This review summarized the research progress of PMOF photocatalysts in the last ten years and analyzed the effects of the spatial structure, porphyrin ligands, porphyrin central metals, and metal nodes of PMOF on the photocatalytic performance. The applications of PMOF-based photocatalysts in H production, CO reduction, pollutant degradation, and sterilization are reviewed. In addition, the mechanism of these processes is described in detail. Finally, some suggestions on the development of PMOF photocatalysts are put forward.