Electrocatalytic Reduction of CO2 to CO with Re-Pyridyl-NHCs: Proton Source Influence on Rates and Product Selectivities

Nalaka P. Liyanage, Hunter A. Dulaney, Aron J. Huckaba, Jonah W. Jurss, Jared H. Delcamp

Research output: Contribution to journalArticlepeer-review

63 Scopus citations

Abstract

A series of four electron-deficient-substituted Re(I) pyridyl N-heterocyclic carbene (pyNHC) complexes have been synthesized, and their electrocatalytic reduction of CO2 has been evaluated by cyclic voltammetry and controlled potential electrolysis experiments. All of the catalysts were evaluated by cyclic voltammetry under inert atmosphere and under CO2 and compared to the known benchmark catalyst Re(bpy)(CO)3Br. Among the four Re-NHC catalysts, Re(pyNHC-PhCF3)(CO)3Br (2) demonstrated the highest catalytic rate (icat/ip)2 at the first and second reduction events with a value of 4 at the second reduction potential (TOF = 0.8 s-1). The rate of catalysis was enhanced through the addition of proton sources (PhOH, TFE, and H2O; TOF up to 100 s-1 (icat/ip)2 = 700). Controlled potential electrolysis shows Faradaic efficiencies (FE) for CO production and accumulated charge for the Re(pyNHC-PhCF3)(CO)3Br catalyst exceed those of the benchmark catalyst in the presence of 2 M H2O (92%, 13 C at 1 h versus 61%, 3 C for the benchmark catalyst) under analogous experimental conditions. A peak FE of 100% was observed during electrolysis with Re(pyNHC-PhCF3)(CO)3Br.

Original languageEnglish
Pages (from-to)6085-6094
Number of pages10
JournalInorganic Chemistry
Volume55
Issue number12
DOIs
StatePublished - Jun 20 2016

Bibliographical note

Publisher Copyright:
© 2016 American Chemical Society.

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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