Effects of Surface Roughness on the Electrochemical Reduction of CO₂ over Cu
Abstract
We have investigated the role of surface roughening on the CO₂ reduction reaction (CO₂RR) over Cu. The activity and product selectivity of Cu surfaces roughened by plasma pretreatment in Ar, O₂, or N₂ were compared with that of electrochemically polished Cu samples. Differences in total and product current densities, the ratio of current densities for HER (the hydrogen evolution reaction) to CO₂RR, and the ratio of current densities for C₂₊ to C₁ products depend on the electrochemically active surface and are nearly independent of plasma composition. Theoretical analysis of an electropolished and roughened Cu surface reveals a higher fraction of undercoordinated Cu sites on the roughened surface, sites that bind CO preferentially. Roughened surfaces also contain square sites similar to those on a Cu(100) surface but with neighboring step sites, which adsorb OC–COH, a precursor to C₂₊ products. These findings explain the increases in the formation of oxygenates and hydrocarbons relative to CO and the ratio of oxygenates to hydrocarbons observed with increasing surface roughness.
Additional Information
© 2020 American Chemical Society. Received: February 29, 2020; Accepted: March 19, 2020; Published: March 19, 2020. 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. K.J. acknowledges the startup funding from Shanghai Jiao Tong University. We also acknowledge Ms. Lien-Chun Weng, Dr. Zhou Lin, and Prof. Martin Head-Gordon for insightful discussions. Author Contributions: K.J. and Y.H. contributed equally to this work. The authors declare no competing financial interest.Attached Files
Supplemental Material - nz0c00482_si_001.pdf
Supplemental Material - nz0c00482_si_002.mp4
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Additional details
- Eprint ID
- 101999
- Resolver ID
- CaltechAUTHORS:20200319-124814828
- Department of Energy (DOE)
- DE-SC0004993
- Shanghai Jiao Tong University
- Created
-
2020-03-19Created from EPrint's datestamp field
- Updated
-
2022-04-26Created from EPrint's last_modified field
- Caltech groups
- JCAP
- Other Numbering System Name
- WAG
- Other Numbering System Identifier
- 1373