It is highly desirable to discover molecular catalysts with controlled selectivity for visible-light-driven CO2 reduction to fuels. In the design of catalysts employing earth-abundant metals, progress has been made for CO production, but formate generation has been observed more rarely. Here, we report a binuclear Co complex bearing a bi-quaterpyridine ligand that can selectively reduce CO2 to HCOO− or CO under visible light irradiation. Selective formate production (maximum of 97%) was obtained with a turnover number of up to 821 in basic acetonitrile solution. Conversely, in the presence of a weak acid, CO2 reduction affords CO with high selectivity (maximum of 99%) and a maximum turnover number of 829. The catalytic process is controlled by the two Co atoms acting synergistically, and the selectivity can be steered towards the desired product by simply changing the acid co-substrate.
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Crystallographic data for [Co2(biqpy)Cl(MeOH)(H2O)](ClO4)3 have been deposited at the Cambridge Crystallographic Data Centre (CCDC no. 1858669. The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.
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The work described in this project was supported by the National Science Foundation of China (grant no. 21703034), Hong Kong University Grants Committee Area of Excellence Scheme (grant no. AoE/P-03–08), Hong Kong Research Grants Council (N_CityU115/18) and the French National Agency for Research (ANR-16-CE05-0010-01). G.C. acknowledges start-up grants from Dongguan University of Technology for high-level talents (grant nos G200906-47, GC200109-17 and KCYKYQD2017016). K.C.L. and M.R. acknowledge partial financial support from CityU Strategic Research Grant no. 7004819 and from the Institut Universitaire de France (IUF), respectively. PhD fellowships to C.C. from Université Sorbonne Paris Cité (USPC) and to B.M. from the China Scholarship Council (CSC student no. 201707040042) are acknowledged. G. Thoraval (Université Paris Diderot) is thanked for the design and preparation of the glassy carbon electrode (3 mm diameter) used during CV experiments. Finally, we thank G. Miyake (Colorado State University) for the sample gift of phenoxazine (Pheno).
The authors declare no competing interests.
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Guo, Z., Chen, G., Cometto, C. et al. Selectivity control of CO versus HCOO− production in the visible-light-driven catalytic reduction of CO2 with two cooperative metal sites. Nat Catal 2, 801–808 (2019). https://doi.org/10.1038/s41929-019-0331-6
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