Bioinspired photo-driven hydrogen evolution systems based on hydrogenases and their mimics

The ever-growing problem of the energy crisis can be addressed with the development of sustainable and renewable sources of energy. The naturally occurring hydrogenases with their active sites provide us with a blueprint to mimic the reaction pathway and mechanism of hydrogen production. This work presents an in-depth summary of the photocatalytic hydrogen production employing 4d/5d-T-metal complexes, quantum dots, and organic dyes as photosensitizers (PSs) and hydrogenase mimics as catalysts. This review is focused on the careful design of both the PSs and catalysts to enhance the overall catalytic activity of artificial photosynthetic systems. The paths followed during the photoinduced electron transfer including the active sites of the catalysts, are discussed to guide the design of robust and efficient photocatalytic hydrogen production systems. The reduction potentials of the catalysts and PSs, change in the free energy values and density functional theory (DFT) calculations are discussed to assess the thermodynamic feasibility of the photoinduced electron transfer processes.