Publication 893

Nat. Catal., 2 (9), 801-808, 2019 DOI:10.1038/s41929-019-0331-6
Selectivity control of CO versus HCOO- production in the visible-light-driven catalytic reduction of CO2 with two cooperative metal sites

School of Environment and Civil Engineering, Dongguan University of Technology, Dongguan, Guangdong, China
Zhenguo Guo, Gui Chen, Lingjing Chen, Hongbo Fan & Shek-Man Yiu
Department of Chemistry and Institute of Molecular Functional Materials, City University of Hong Kong, Hong Kong, China
Université de Paris, Laboratoire d’Electrochimie Moléculaire, CNRS, Paris, France
Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China

Abstract
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.