Visible-Light-Driven H₂ Evolution with Cobalt Complexes in Aqueous Solution: Theoretical and Experimental Study

The development of new catalysts based on nonprecious metals for photocatalytic H₂ evolution reaction (HER) is a very challenging endeavor. In this work, we used density functional theory (DFT) to design a high performance photocatalyst based on Co^III(dmgH)₂pyCl. The sample was then prepared and used for photocatalytic HER under visible light irradiation with Eosin-Y (EY^2–) and triethanolamine (TEOA) as a photosensitizer and electron donor, respectively. The feasibility and rationality of the DFT design were verified by the consistency between the photocatalytic performances and the theoretical results. The developed catalyst even showed the capability of splitting of water for H₂ evolution. As for the most promising Co^III(dmgH)₂(pyrazine)­Cl, 1356 μmol of H₂ can be produced over 25 mg of catalyst after irradiation for 3 h. The deactivation and the mechanism for the evolution of H₂ over the sample were further investigated. We believe that this study provides an effective strategy for the design of highly efficient photocatalysts for HER.