Ni(II) and Cu(II) complexes derived from thiophene-2,5-bis(thiosemicarbazone) as unprecedented templates for photocatalytic hydrogen production

• Published in: Molecular catalysis Vol. 566; p. 114431
• Main Authors: Santarelli, Andrés, Brandl, Cândida A., Cechin, Camila N., Bortolotto, Tanize, Daudt, Natália de Freitas, Burrow, Robert A., Lang, Ernesto Schulz, Tirloni, Bárbara, Ledesma, Gabriela N.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-09-2024
• Subjects: HER; Heterocyclic bis(thiosemicarbazone); Nickel complex; Photocatalyst; Titanium dioxide; Nickel complex; Heterocyclic bis(thiosemicarbazone); HER; Titanium dioxide; Photocatalyst
• ISSN: 2468-8231; 2468-8231
• DOI: 10.1016/j.mcat.2024.114431

•Ni(II) and Cu(II) bis(thiosemicarbazone) complexes were synthesized.•TiO2 immobilized photocatalytic solids were prepared via sol-gel method.•Photocatalysts assessed for hydrogen production through light-driven water splitting.•Mesoporous NiL@m-TiO2 showed 20-fold higher catalytic activity than m-TiO2 matrix.
The reaction of thiophene-2,5-dicarboxaldehyde-bis-thiosemicarbazone (H2L) with nickel and copper salts in methanol yields the N2S2-coordinated complexes of formula ML (M=Ni,Cu). This work describes their characterization by NMR, FT-IR, Raman, UV-Vis absorption spectroscopy, thermogravimetric analysis and x-ray diffraction. The immobilization of both NiL and CuL complexes was succeed preparing TiO2-based photocatalysts by the sol-gel method, that were studied by solid-state UV-vis diffuse reflectance, energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), N2 adsorption-desorption and powder X-ray diffraction. The synthesized composites were also evaluated as photocatalysts in the hydrogen olution reaction (HER) with the mesoporous NiL@m-TiO2 proven to be more active than CuL@m-TiO2, with a total amount of released hydrogen of ca. 6200 μmol g−1 of composite, after 6 h of irradiation with a 300 W Hg/Xe lamp.
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