Photocatalytic Hydrogen Production Activity and Mechanism of New Nickel-Based Sulfur Complexes in Aqueous Solution.

The development of industry and the increase in population have caused energy shortages and environmental pollution problems. Developing clean and storable new energy is identified as a key way to solve the problems above. Hydrogen is viewed as the most potential energy carrier due to its high calorific value and pollution-free. To convert solar energy into hydrogen energy, three nickel-based catalysts, Ni(aps)(pys) (aps=2-amino-2-phenylacetic salicylaldehyde) (1), Ni(ads)(pys) (ads=aniline salicylaldehyde, pys=pyridine-2-thiolate) (2), Ni(acs)(pys) (acs=aniline 5-chlorosalicylaldehyde) (3), were synthesized and explored as photocatalysts for hydrogen production. A three-component photocatalytic system for hydrogen production was constructed using target complex as photocatalyst, triethanolamine (TEOA) as electron sacrificial agent and fluorescein (FL) as photosensitizer. Under the optimum conditions, about 1504 μmol of H can be obtained with 25 mg catalyst 2 after 3 hours of irradiation. Finally, the hydrogen-production mechanism was discussed by experimental and theoretical methods.