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- Title
A Nickel Dithiolate Water Reduction Catalyst Providing Ligand-Based Proton-Coupled Electron-Transfer Pathways.
- Authors
Koshiba, Keita; Yamauchi, Kosei; Sakai, Ken
- Abstract
A nickel pyrazinedithiolate ([Ni(dcpdt)2]2−; dcpdt=5,6-dicyanopyrazine-2,3-dithiolate), bearing a NiS4 core similar to the active center of [NiFe] hydrogenase, is shown to serve as an efficient molecular catalyst for the hydrogen evolution reaction (HER). This catalyst shows effectively low overpotentials for HER (330-400 mV at pH 4-6). Moreover, the turnover number of catalysis reaches 20 000 over the 24 h electrolysis with a high Faradaic efficiency, 92-100 %. The electrochemical and DFT studies reveal that diprotonated one-electron-reduced species (i.e., [NiII(dcpdt)(dcpdtH2)]− or [NiII(dcpdtH)2]−) forms at pH<6.4 via ligand-based proton-coupled electron-transfer (PCET) pathways, leading to electrocatalytic HER without applying the highly negative potential required to generate low-valent nickel intermediates. This is the first example of catalysts exhibiting such behavior.
- Subjects
NICKEL compounds; HYDROGEN evolution reactions; ELECTRON-transfer catalysis; HYDROGENASE; FARADAIC current
- Publication
Angewandte Chemie, 2017, Vol 129, Issue 15, p4311
- ISSN
0044-8249
- Publication type
Article
- DOI
10.1002/ange.201700927