Light-driven hydrogen production catalysed by transition metal complexes in homogeneous systems

The development of heterogeneous catalytic systems for hydrogen production from water under light irradiation has been investigated during last three decades. Homogeneous photocatalysts, however, are very attractive in sense that their chemical and photochemical properties can be understood and tuned on molecular level. Moreover, in homogeneous systems catalysts may be covalently bound to photosensitizers, which leads to more efficient electron transfer. Molecular devices for water splitting based on such a systems are of great interest. In this review, we summarize recent progresses in the synthesis, properties and application of metal-based molecular catalysts for photoinduced hydrogen evolution in homogeneous systems.