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Cobalt-Porphyrin Catalyzed Reduction of CO2: Radiation Chemical, Photochemical, and Electrochemical Studies



D Behar, T Dhanasekaran, Pedatsur Neta, C M. Hosten, D Ejeh, P Hambright, E Fujita


Several cobalt porphyrins (CoP) have been reduced by radiation chemical, photochemical, and electrochemical methods, in aqueous and organic solvents. In aqueous solutions, the CoIP is also observed in organic solvents even in the presence of CO2. One-electron reduction of CoIP leads to formation of a species which is observed as a transient intermediate by pulse radiolysis in aqueous solutions and as a stable product following reduction by Na in tetrahydrofuran solutions. The spectrum of this species is not the characteristic spectrum of a metalloporphyrin [pi]-radical anion and is ascribed to Co0P. This species binds and reduces CO2. Catalytic formation of CO and HCO2- is confirmed by photochemical experiments in acetonitrile solutions containing triethylamine as a reductive quencher. Catalytic reduction of CO2 is also confirmed by cyclic voltammetry in acetonitrile and butyronitrile solutions and is shown to occur at the potential at which CoIP is reduced to Co0P. As compared with CoTPP, fluorinated derivatives are reduced, and catalyze CO2 reduction, at less negative potentials.
Journal of Physical Chemistry


Behar, D. , Dhanasekaran, T. , Neta, P. , Hosten, C. , Ejeh, D. , Hambright, P. and Fujita, E. (1998), Cobalt-Porphyrin Catalyzed Reduction of CO<sub>2</sub>: Radiation Chemical, Photochemical, and Electrochemical Studies, Journal of Physical Chemistry, [online], (Accessed April 13, 2024)
Created February 25, 1998, Updated February 17, 2017