Chinese Journal of Catalysis ›› 2021, Vol. 42 ›› Issue (2): 310-319.DOI: 10.1016/S1872-2067(20)63644-0

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Selective photocatalytic reduction of CO2 to CO mediated by a [FeFe]-hydrogenase model with a 1,2-phenylene S-to-S bridge

Minglun Cheng, Xiongfei Zhang, Yong Zhu, Mei Wang*()   

  1. State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, Liaoning, China
  • Received:2020-03-17 Accepted:2020-05-09 Online:2021-02-18 Published:2021-01-21
  • Contact: Mei Wang
  • About author:*Tel: +86-411-84986246; E-mail: symbueno@dlut.edu.cn
  • Supported by:
    National Natural Science Foundation of China(21673028);National Natural Science Foundation of China(21373040)

Abstract:

Photocatalytic reduction of CO2 to CO is a promising approach for storing solar energy in chemicals and mitigating the greenhouse effect of CO2. Our recent studies revealed that [(μ-bdt)Fe2(CO)6] (1, bdt = benzene-1,2-dithiolato), a [FeFe]-hydrogenase model with a rigid and conjugate S-to-S bridge, was catalytically active for the selective photochemical reduction of CO2 to CO, while its analogous complex [(μ-edt)Fe2(CO)6] (2, edt = ethane-1,2-dithiolato) was inactive. In this study, it was found that the turnover number of 1 for CO evolution reached 710 for the 1/[Ru(bpy)3]2+/BIH (BIH = 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]-imidazole) system under optimal conditions over 4.5 h of visible-light irradiation, with a turnover frequency of 7.12 min-1 in the first hour, a high selectivity of 97% for CO, and an internal quantum yield of 2.8%. Interestingly, the catalytic selectivity of 1 can be adjusted and even completely switched in a facile manner between the photochemical reductions of CO2 to CO and of protons to H2 simply by adding different amounts of triethanolamine to the catalytic system. The electron transfer in the photocatalytic system was studied by steady-state fluorescence and transient absorption spectroscopy, and a plausible mechanism for the photocatalytic reaction was proposed.

Key words: Catalytic selectivity, Carbon dioxide reduction, Carbon monoxide, Diiron complex, Hydrogenase model, Photocatalysis