Τίτλος:
Heteroleptic thiolate diamine nickel complexes: Noble-free-metal catalysts in electrocatalytic and light-driven hydrogen evolution reaction
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
Three mononuclear heteroleptic nickel complexes bearing the non-innocent o-aminobenzenethiolate (2-amnt) ligand and different diamine ligands, namely, [Ni(2-amnt)(o-phen)] (o-phen = o-phenylenediamine) (1), [Ni(2-amnt)(3,4-daba)] (3,4-daba = 3, 4-diamino benzoic acid) (2) and [Ni(2-amnt)(dmnt)] (dmnt = diaminomaleonitrile) (3), were synthesized and characterized. Complexes 1–3 are active homogeneous proton reduction electrocatalysts in dimethylformamide with trifluoroacetic acid as a proton source. All the three complexes are tested in light-driven hydrogen evolution reaction, indicating different catalytic efficiencies. Thus, although complex 3 indicates no catalytic action, both complexes 1 and 2 catalyze H2 evolution in water-dimethylformamide solutions using fluorescein (Fl) as a photosensitizer. Complex 2 acts as a homogeneous catalyst reached 834 turnovers (TON); whereas 1, despite being active in hydrogen evolution reaction (HER), decomposes to form nanomaterials. DFT calculations combined with electrochemical and spectroscopic data were employed to investigate the catalytic mechanism for H2 formation as well as to unravel the key factors that influence the relative catalytic efficiencies. The proposed catalytic pathway involves ligand-based reduction and protonation steps followed by the formation of a nickel-hydride intermediate that reacts with a solution proton to generate H2 via a very low energy transition state. © 2021 Hydrogen Energy Publications LLC
Συγγραφείς:
Kamatsos, F.
Drosou, M.
Mitsopoulou, C.A.
Περιοδικό:
International Journal of Hydrogen Energy
Εκδότης:
ELSEVIER SCIENCE LTD.
Λέξεις-κλειδιά:
Amines; Benzoic acid; Dimethylformamide; Electrocatalysts; Hydrogen; Hydrogen evolution reaction; Ligands; Photosensitizers; Reduction; Synthesis (chemical); Trifluoroacetic acid, 3 ,4-diamino benzoic acid; Catalytic efficiencies; Catalytic mechanisms; Diaminomaleonitrile; Energy transition state; Homogeneous catalyst; O- phenylenediamine; Spectroscopic data, Nickel compounds
DOI:
10.1016/j.ijhydene.2021.02.005
