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

Published

February 25, 1998

Author(s)

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

Abstract

Several cobalt porphyrins (CoP) have been reduced by radiation chemical, photochemical, and electrochemical methods, in aqueous and organic solvents. In aqueous solutions, the Co^IP is also observed in organic solvents even in the presence of CO₂. One-electron reduction of Co^IP 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 Co^IP is reduced to Co⁰P. As compared with CoTPP, fluorinated derivatives are reduced, and catalyze CO₂ reduction, at less negative potentials.

Citation

Journal of Physical Chemistry

Volume

102

Issue

17

Pub Type

Journals

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Citation

Behar, D. , Dhanasekaran, T. , Neta, P. , Hosten, C. , Ejeh, D. , Hambright, P. and Fujita, E. (1998), Cobalt-Porphyrin Catalyzed Reduction of CO₂: Radiation Chemical, Photochemical, and Electrochemical Studies, Journal of Physical Chemistry, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=832033 (Accessed December 3, 2024)