Chinese Journal of Catalysis ›› 2018, Vol. 39 ›› Issue (3): 446-452.DOI: 10.1016/S1872-2067(18)63024-4

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Visible light-driven oxygen evolution using a binuclear Ru-bda catalyst

Fei Lia, Congying Xua, Xiaohong Wanga, Yong Wanga, Jian Dua, Licheng Suna,b   

  1. a State Key Laboratory of Fine Chemicals, DUT-KTH Joint Education and Research Center on Molecular Devices, Dalian University of Technology(DUT), Dalian 116024, Liaoning, China;
    b Department of Chemistry, School of Chemical Science and Engineering, KTH Royal Institute of Technology, 10044 Stockholm, Sweden
  • Received:2017-10-17 Revised:2018-01-06 Online:2018-03-18 Published:2018-03-10
  • Contact: 10.1016/S1872-2067(18)63024-4
  • Supported by:

    This work was supported by the National Basic Research Program of China (973 Program, 2014CB239402), the National Natural Science Foundation of China (21476043), the Fundamental Research Funds for the Central Universities (DUT17ZD204), and the Swedish Energy Agency and K&A Wallenberg Foundation.

Abstract:

Binuclear ruthenium complexes bearing the 2,2'-bipyridine-6,6'-dicarboxylate (bda) ligand have been demonstrated to be highly active catalysts towards water oxidation with CeIV as an oxidant. However, the catalytic properties of ruthenium dimers have not yet been explored for visible light-driven water oxidation. Herein, the photocatalytic performance of a dipyridyl propane-bridged ruthenium dimer 2 was investigated in comparison with its monomeric precursor,[Ru(bda)(pic)2] (1), in CH3CN/phosphate buffer mixed solvent in a three-component system including a photosensitizer and a sacrificial electron acceptor. Experimental results showed that the activity of each catalyst was strongly dependent on the content of CH3CN in the phosphate buffer, which not only affected the driving force for water oxidation, but also altered the kinetics of the reaction, probably through different mechanisms associated with the O-O bond formation. As a result, dimer 2 showed significantly higher activity than monomer 1 in the solvent containing a low content of CH3CN, and comparable activities were attained with a high content of CH3CN in the solvent. Under the optimal conditions, complex 2 achieved a turnover number of 638 for photocatalytic O2 evolution.

Key words: Water oxidation, Binuclear ruthenium catalyst, Photocatalysis, Solvent effect, Kinetics