Hexanuclear ring cobalt complex for photochemical CO2 to CO conversion

Photosynthesis in nature has been deemed as the most significant biochemical reaction, which maintains a relatively stable content of O-2 and CO2 in the atmosphere. Herein, for a deeper comprehension of natural photosynthesis, an artificial photosynthesis model reaction of photochemical CO2 to CO conversion (CO2 +2H(+) + 2e(-) -> CO + H2O) catalyzed by a homogeneous hexanuclear ring cobalt complex {K-2[CoO3PCH2N(CH2CO2)(2)]}(6) (Co6 complex) is developed. Using the [Ru(bpy)(3)](2+) as a photosensitizer and TEOA as a sacrificial electron donor, an optimal turnover frequency of 503.3 h(-1) and an apparent quantum efficiency of 0.81% are obtained. The good photocatalytic CO2 reduction performance is attributed to the efficient electron transfer between Co6 complex and [Ru(bpy)(3)](2+), which boosts the photogenerated carriers separation of the photosensitizer. It is confirmed by the UV curves, light-assisted UV-vis curves, steady-state photoluminescence spectra and real-time laser flash photolysis experiments. In addition, the proposed catalytic mechanism for CO2 reduction reaction catalyzed by the Co6 complex is explored by the potassium thiocyanate poison experiment, Pourbaix diagram and density functional theory calculations. (C) 2022, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

Photosynthesis is considered the most crucial biochemical reaction in nature, as it regulates the stable levels of O-2 and CO2 in the atmosphere. Researchers have developed an artificial photosynthesis model reaction that converts CO2 to CO using photochemical methods. The study demonstrates that efficient electron transfer plays a significant role in achieving excellent photocatalytic CO2 reduction performance. Furthermore, the researchers explored the catalytic mechanism of the CO2 reduction reaction.