A Highly Selective and Robust Co(II)-Based Homogeneous Catalyst for Reduction of CO 2 to CO in CH 3 CN/H 2 O Solution Driven by Visible Light.

Visible-light driven reduction of CO2 into chemical fuels has attracted enormous interest in the production of sustainable energy and reversal of the global warming trend. The main challenge in this field is the development of efficient, selective, and economic photocatalysts. Herein, we report a Co(II)-based homogeneous catalyst, [Co(NTB)CH3 CN](ClO4 )2 (1, NTB = tris(benzimidazolyl-2-methyl)amine), which shows high selectivity and stability for the catalytic reduction of CO2 to CO in a water-containing system driven by visible light, with turnover number (TON) and turnover frequency (TOF) values of 1179 and 0.032 s-1 , respectively, and selectivity to CO of 97%. The high catalytic activity of 1 for photochemical CO2 -to-CO conversion is supported by the results of electrochemical investigations and DFT calculations.