Development of Re(I) Photocatalysts for the Photochemical Reduction of Atmospheric CO2

  • Author / Creator
    Murphy, Elizabeth A
  • Three new Re(I) photocatalysts were prepared by synthesizing imidazole and imidazolium dyes based on carbazolyl dicyanobenzene derivatives and physically linking them to a Re metal centre for the photochemical reduction of CO2. The imidazolium dyes were of interest because they are precursors to free non-heterocyclic compounds which can be generated by deprotonation. All three photocatalysts, Re-2, Re-8, and Re-9, were successful in the reduction of CO2, yielding CO as a reduction product and methane as a side product. The CO2 reduction reactions with each catalyst began with an initial burst in activity followed by a decrease due to the precipitation of a solid in the reaction solution that reflected/blocked incident light. One of the Re-NHC photocatalysts, Re-8, resulted in the highest activity out of the three compounds, with an initial turnover frequency of 47 h–1. The source of the produced methane was identified as the cleavage of a methyl group from the electron donor, 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzimidazole, by a radical reaction chain unrelated to the reduction of CO2. These compounds show promising results as photocatalysts for the reduction of CO2 to CO and can be translated to heterogeneous systems via electro-polymerization of the carbazole moieties on to indium-tin oxide and carbon electrodes.

  • Subjects / Keywords
  • Graduation date
    Fall 2023
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
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