(726f) Directing Selectivity of Electrochemical CO2 Reduction at Plasmonic Cathodes
We study this reaction in a custom temperature-controlled gas flow cell. CO2 flowing through the cell can be pre-mixed in precise ratios with argon for CO2 partial pressure experiments. The cell temperature can be held at a constant 22 C during both dark and illuminated experiments and permits temperature variation studies. Precise product quantification is achieved by an in-line gas chromatograph for gaseous products and by ex situ NMR for liquid products. We explore variations in product distribution with changes in electrochemical potential, illumination intensity, light wavelength, and the plasmonic catalyst. We demonstrate that illumination of a voltage-biased plasmonic silver cathode selectively enhances CO2 reduction products while simultaneously suppressing undesired hydrogen evolution. Strikingly, methanol is produced only upon illumination, representing an improvement in both selectivity and efficiency. These results indicate that by tuning the cathode structure and composition we can achieve greater plasmonic enhancements in selectivity and activity towards hydrocarbon products from CO2 reduction.
This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993.
The work is supported by the National Science Foundation under Grant No. 1106400 (Graduate Research Fellowship) and CBET-1653430 (CAREER, Electrochemical Systems Program).
Work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.