A Noble-Metal-Free Nickel(II) Polypyridyl Catalyst for Visible-Light-Driven Hydrogen Production from Water

• Published in: Chemphyschem Vol. 16; no. 14; pp. 2925 - 2930
• Main Authors: Yuan, Yong-Jun, Lu, Hong-Wei, Tu, Ji-Ren, Fang, Yong, Yu, Zhen-Tao, Fan, Xiao-Xing, Zou, Zhi-Gang
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 05.10.2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: homogeneous catalysis; hydrogen evolution; Nickel; Photocatalysis; photochemistry; nickel; hydrogen evolution; homogeneous catalysis; photocatalysis; photochemistry
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.201500530

The complex [Ni(bpy)3]2+ (bpy=2,2′‐bipyridine) is an active catalyst for visible‐light‐driven H2 production from water when employed with [Ir(dfppy)2(Hdcbpy)] [dfppy=2‐(3,4‐difluorophenyl)pyridine, Hdcbpy=4‐carboxy‐2,2′‐bipyridine‐4′‐carboxylate] as the photosensitizer and triethanolamine as the sacrificial electron donor. The highest turnover number of 520 with respect to the nickel(II) catalyst is obtained in a 8:2 acetonitrile/water solution at pH 9. The H2‐evolution system is more stable after the addition of an extra free bpy ligand, owing to faster catalyst regeneration. The photocatalytic results demonstrate that the nickel(II) polypyridyl catalyst can act as a more effective catalyst than the commonly utilized [Co(bpy)3]2+. This study may offer a new paradigm for constructing simple and noble‐metal‐free catalysts for photocatalytic hydrogen production. A noble cause: A three‐component homogeneous catalytic system, composed of a tris‐(2,2′‐bipyridine) nickel(II) catalyst, an iridium(III) photosensitizer, and triethanolamine in aqueous acetonitrile, is catalytically active for solar H2 generation, with up to 520 turnovers over 12 h of visible‐light irradiation.