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Title: Ferrous ions as catalysts for photochemical reduction of CO{sub 2} in homogeneous solutions

Abstract

Ferrous ions are found to catalyze the photochemical reduction of CO{sub 2} to CO in acetonitrile (ACN) solutions containing triethylamine (TEA) or triethanolamine (TEOA) as reductive quenchers and p-terphenyl (TP) as a photosensitizer. TP is photoreduced to form the radical anion, TP{sup {sm_bullet}{minus}}, which reduces Fe(II) ions. The rate constant for the reduction of Fe(II) by TP{sup {sm_bullet}{minus}} was determined by pulse radiolysis in ACN/TEOA solutions and found to be (1.2 {+-} 0.4) x 10{sup 8} L mol{sup {minus}1}s{sup {minus}1}. The Fe(I) ions produced are expected to react with Co{sub 2} to form an adduct that is equivalent to the adduct known to be formed upon reaction of CO{sub 2}{sup {sm_bullet}{minus}} with Fe(II) complexes. Subsequent reduction of the Fe-CO{sub 2} adduct leads to formation of CO. Fe(I) can also undergo protonation and form H{sub 2}. After extensive irradiation, photochemical production of CO stops, probably due to competition between CO and CO{sub 2} for the Fe(I) binding sites. Addition of CO to the solution enhances the photochemical production of H{sub 2}.

Authors:
;
Publication Date:
Research Org.:
National Inst. of Standards and Technology, Gaithersburg, MD (US)
Sponsoring Org.:
USDOE
OSTI Identifier:
20075897
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory
Additional Journal Information:
Journal Volume: 104; Journal Issue: 19; Other Information: PBD: 18 May 2000; Journal ID: ISSN 1089-5639
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; IRON COMPOUNDS; CATALYSTS; REDUCTION; CARBON DIOXIDE; SOLUTIONS; ELECTROCHEMISTRY; PHOTOCHEMICAL REACTIONS; RADIOLYSIS

Citation Formats

Grodkowski, J., and Neta, P. Ferrous ions as catalysts for photochemical reduction of CO{sub 2} in homogeneous solutions. United States: N. p., 2000. Web. doi:10.1021/jp993456f.
Grodkowski, J., & Neta, P. Ferrous ions as catalysts for photochemical reduction of CO{sub 2} in homogeneous solutions. United States. doi:10.1021/jp993456f.
Grodkowski, J., and Neta, P. Thu . "Ferrous ions as catalysts for photochemical reduction of CO{sub 2} in homogeneous solutions". United States. doi:10.1021/jp993456f.
@article{osti_20075897,
title = {Ferrous ions as catalysts for photochemical reduction of CO{sub 2} in homogeneous solutions},
author = {Grodkowski, J. and Neta, P.},
abstractNote = {Ferrous ions are found to catalyze the photochemical reduction of CO{sub 2} to CO in acetonitrile (ACN) solutions containing triethylamine (TEA) or triethanolamine (TEOA) as reductive quenchers and p-terphenyl (TP) as a photosensitizer. TP is photoreduced to form the radical anion, TP{sup {sm_bullet}{minus}}, which reduces Fe(II) ions. The rate constant for the reduction of Fe(II) by TP{sup {sm_bullet}{minus}} was determined by pulse radiolysis in ACN/TEOA solutions and found to be (1.2 {+-} 0.4) x 10{sup 8} L mol{sup {minus}1}s{sup {minus}1}. The Fe(I) ions produced are expected to react with Co{sub 2} to form an adduct that is equivalent to the adduct known to be formed upon reaction of CO{sub 2}{sup {sm_bullet}{minus}} with Fe(II) complexes. Subsequent reduction of the Fe-CO{sub 2} adduct leads to formation of CO. Fe(I) can also undergo protonation and form H{sub 2}. After extensive irradiation, photochemical production of CO stops, probably due to competition between CO and CO{sub 2} for the Fe(I) binding sites. Addition of CO to the solution enhances the photochemical production of H{sub 2}.},
doi = {10.1021/jp993456f},
journal = {Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory},
issn = {1089-5639},
number = 19,
volume = 104,
place = {United States},
year = {2000},
month = {5}
}