Structure-Functional Analysis of Hydrogen Production Catalyzed by Molecular Cobalt Complexes with Pentadentate Ligands in Aqueous Solutions

Hydrogen production from sunlight and water represents one promising solution to resolve the environmental problems caused by the consumption of fossil fuels and to meet the increasing global energy demands. Catalysts based on transition metal complexes have been extensively studied for electro- and photocatalytic production of hydrogen. Among the reported catalysts, molecular cobalt complexes have received special attention for hydrogen production over the past years. In this review, the recent progresses for electro- and photocatalytic production of hydrogen in aqueous solutions catalyzed by Co complexes with pentadentate ligands, with an emphasis of those developed in our lab, are discussed. Mechanistic investigations as well as future directions for hydrogen production by Co complexes are also discussed.