Identifying Structure–Selectivity Correlations in the Electrochemical Reduction of CO2: A Comparison of Well‐Ordered Atomically Clean and Chemically Etched Copper Single‐Crystal Surfaces

The identification of the active sites for the electrochemical reduction of CO2 (CO2RR) to specific chemical products is elusive, owing in part to insufficient data gathered on clean and atomically well‐ordered electrode surfaces. Here, ultrahigh vacuum based preparation methods and surface science...

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Bibliographic Details
Published in:Angewandte Chemie International Edition 2021-08, Vol.60 (35), p.19169-19175
Main Authors: Scholten, Fabian, Nguyen, Khanh‐Ly C., Bruce, Jared P., Heyde, Markus, Roldan Cuenya, Beatriz
Format: Article
Language:English
Subjects:
Carbon dioxide
Chemical reduction
Copper
Crystal defects
Crystal structure
Crystal surfaces
Crystals
electro-reduction
Electrochemical etching
Electrochemistry
Etching
Gas chromatography
Hydrocarbons
Selectivity
Single crystals
Ultrahigh vacuum
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Summary:The identification of the active sites for the electrochemical reduction of CO2 (CO2RR) to specific chemical products is elusive, owing in part to insufficient data gathered on clean and atomically well‐ordered electrode surfaces. Here, ultrahigh vacuum based preparation methods and surface science characterization techniques are used with gas chromatography to demonstrate that subtle changes in the preparation of well‐oriented Cu(100) and Cu(111) single‐crystal surfaces drastically affect their CO2RR selectivity. Copper single crystals with clean, flat, and atomically ordered surfaces are predicted to yield hydrocarbons; however, these were found experimentally to favor the production of H2. Only when roughness and defects are introduced, for example by electrochemical etching or a plasma treatment, are significant amounts of hydrocarbons generated. These results show that structural and morphological effects are the key factors determining the catalytic selectivity of CO2RR. Subtle changes in the preparation of well‐oriented Cu(100) and Cu(111) single‐crystal surfaces affect their CO2RR selectivity. Clean, flat, atomically ordered surfaces are predicted to yield hydrocarbons; but these actually favor production of H2. Only when roughness and defects are introduced, significant amounts of hydrocarbons are generated. Structural and morphological effects are the key factors determining the catalytic selectivity of CO2RR.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.202103102