MOF-based photocatalysts for hydrogen generation by water splitting

The ever-increasing demand for energy and the depletion of fossil fuel have made the use of renewable energy imperative. The use of hydrogen gas for energy generation is foreseen as an ideal source of energy for the future. It is beneficial due to its high combustion efficiency, serves as a clean source of energy generating water as the only by-product. Water splitting produces hydrogen gas as a sustainable source of energy generation. However, as a result of the slow kinetics of this reaction, catalysts are required. Metal-organic frameworks (MOFs) are a class of porous materials composed of metal atoms or clusters, connected by organic ligands. They have received quite a lot of attention in photocatalytic water splitting recently due to their desirable topology, controllable synthesis, high surface area, suitable HOMO-LUMO distance leading to desirable band gaps. These properties give MOFs an edge over previously used photo catalysts. This section explains the fundamentals of MOFs-based photocatalytic water splitting, strategies for better performance of MOFs for photocatalytic water splitting such as modification of metal ion and organic linker, dye-sensitization of the MOF material, cocatalyst encapsulation, heterojunction formation of MOF-semiconductor composites, and multiple approaches toward achieving more efficient photocatalytic water splitting. Some challenges and future prospects are also stated.