Manipulating Selectivity of Electrochemical CO2 Reduction at a Cu–Ag Plasmonic Catalyst | AIChE

Manipulating Selectivity of Electrochemical CO2 Reduction at a Cu–Ag Plasmonic Catalyst


Subramani, A. - Presenter, University of California, Berkeley
Corson, E. R., University of California, Berkeley
McCloskey, B., University of California, Berkeley
Carbon dioxide (CO2) can be reduced to prevent the introduction of further CO2 into the atmosphere, while creating other useful carbon-containing products that can be used in chemical processes or as fuels. Plasmonic cathodes are a promising route for CO2 reduction because they allow for the reduction of CO2 at low overpotentials and can help direct selectivity for more complex products under illumination.

To this end, silver-coated copper nanocorals on silver foil were investigated as a plasmonic catalyst for CO2reduction, and were found to produce many products, with some containing as many as three carbons. Furthermore, the nanocorals not only are more stable under reaction conditions than thin-film silver plasmonic electrodes, they also have a higher absorbance in the visible range, as measured by UV-visible spectrometry. Ultimately, 15 products were identified during CO2 electrolysis at nanocorals illuminated with 365 nm light (corresponding to the plasmon resonance of Ag); major products (greater that 1% Faradaic efficiency) requiring more than 2 electrons were methane, ethylene, and ethanol. Under illumination and at low overpotentials (-0.6 to -0.8 VRHE), this catalyst also promoted CO2 reduction products such as carbon monoxide over hydrogen evolution, the undesired decomposition of the aqueous electrolyte. At overpotentials between -0.8 and -1.0 VRHE there was an increase in higher carbon products. Taken together, this makes copper–silver nanocorals a very promising catalyst for CO2 reduction reactions as it increases selectivity for more complex CO2 reduction products at relatively low overpotentials.

This work was largely supported by the National Science Foundation under Grant No. CBET-1653430. This material is based upon work performed at 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 No. DE-SC0004993. 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.