Optoelectronic Alteration of Metal-Organic Frameworks for Enhanced Photocatalytic Water Splitting Activity Under Solar Radiation

Metal-organic frameworks (MOFs) have been increasingly popular in photocatalytic water-splitting research areas due to their unique, tunable porosity, high stability, large surface activity, and manipulative topology. However, the incapability of MOFs in harvesting broad-solar irradiation and rapid electron-hole pairs recombination has limited their efficiency in practical applications, and their structures allow researchers to manipulate them toward better efficiency. Also, linker modification is achieved by reclaiming the organic linker, which constructs MOFs by functionalizing, changing the ligand's length, and using an aided organic linker. In addition, being a free space in their structure gives this opportunity to modify them easily with other compounds such as inorganic complex compounds and nanoparticles by incorporation, impregnation, and ship-in-a-bottle methods. The objectives of this review article are three-fold. First, to emphasize understanding of the fundamental correlation among promising strategies to improve the optoelectronic properties of MOFs such as light-harvesting capability and photoinduced electron-hole pairs for photocatalytic reactions involving water splitting reaction under broad solar irradiation. Second, to systematically summarize the organic linker modification and incorporation of polyoxometalate, coordination metal complexes, and various nanoparticles. Third, to discuss challenges and future research directions for the development of broad solar band activation of MOFs for photocatalysis purposes.