Probing Photocatalytic Hydrogen Evolution of Cobalt Complexes: Experimental and Theoretical Methods

This work reports on the synthesis and characterization of a series of Schiff-base cobalt(III) complexes 1 similar to 4 that exhibit an obvious catalytic activity for hydrogen production in aqueous solution using fluorescein (FL) and triethanolamine (TEOA) as photosensitizer and electron donor, respectively. The complexes display the capability of splitting of water for H-2 evolution. Under optimized conditions, complex 3 shows better properties for photocatalysis, 25 mg of which can release 152.3 mu mol of H2 after irradiation for 3 h. The mechanism for light-driven H-2 production was explored by experiments and density functional theory (DFT). Meanwhile, the reason of releasing hydrogen was explained theoretically in detail. The research results will help to understand the interaction of cobalt complexes with the photosensitizer and design new photocatalysis for the future.