title: Improving the efficiency of electrochemical CO2 reduction using immobilized manganese complexes.
abstract: Immobilization of [Mn(bpy)(CO)3Br], (1) and [Mn(bpy((t)Bu)2)(CO)3Br] (2, where (bpy((t)Bu)2) = 4,4'-di-tert-butyl-2,2'-bipyridine) in Nafion/multi-walled carbon nanotubes (MWCNT) on glassy carbon yielded highly active electrodes for the reduction of CO2 to CO in aqueous solutions at pH 7. Films incorporating have significantly improved selectivity towards CO2, with CO : H2 ∼ 1 at -1.4 V vs. SCE, exceeding that for the previously reported /MWCNT/Nafion electrode. Furthermore, we report the synthesis and subsequent electrochemical characterization of two new substituted Mn(i) bipyridine complexes, [Mn(bpy(COOH)2)(CO)3Br] (3) and [Mn(bpy(OH)2)(CO)3Br] (4) (where (bpy(COOH)2) = 4,4'-di-carboxy-2,2'-bipyridine and (bpy(OH)2) = 4,4'-di-hydroxy-2,2'-bipyridine). Both 3 and 4 were found to have some activity towards CO2 in acetonitrile solutions; however once immobilized in Nafion membranes CO2 reduction was found to not occur at significant levels.
authors.affiliation: Department of Chemistry, Stephenson Institute for Renewable Energy, The University of Liverpool, L69 7ZD, Liverpool, UK. a.j.cowan@liverpool.ac.uk.
authors.forename: James J
authors.initials: JJ
authors.lastname: Walsh
authors.affiliation: Department of Chemistry, Stephenson Institute for Renewable Energy, The University of Liverpool, L69 7ZD, Liverpool, UK. a.j.cowan@liverpool.ac.uk.
authors.forename: Charlotte L
authors.initials: CL
authors.lastname: Smith
authors.affiliation: Department of Chemistry, Stephenson Institute for Renewable Energy, The University of Liverpool, L69 7ZD, Liverpool, UK. a.j.cowan@liverpool.ac.uk.
authors.forename: Gaia
authors.initials: G
authors.lastname: Neri
authors.affiliation: Department of Chemistry, Stephenson Institute for Renewable Energy, The University of Liverpool, L69 7ZD, Liverpool, UK. a.j.cowan@liverpool.ac.uk.
authors.forename: George F S
authors.initials: GF
authors.lastname: Whitehead
authors.affiliation: Department of Chemistry, Stephenson Institute for Renewable Energy, The University of Liverpool, L69 7ZD, Liverpool, UK. a.j.cowan@liverpool.ac.uk.
authors.forename: Craig M
authors.initials: CM
authors.lastname: Robertson
authors.affiliation: Department of Chemistry, Stephenson Institute for Renewable Energy, The University of Liverpool, L69 7ZD, Liverpool, UK. a.j.cowan@liverpool.ac.uk.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Cowan