Facet-switching of rate-determining step on copper in CO<sub>2</sub>-to-ethylene electroreduction.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38857407.
- Also identified by DOI 10.1073/pnas.2400546121 and PMC identifier 11194607.
- Licence recorded as CC BY-NC-ND.
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Abstract
Reduction of carbon dioxide (CO<sub>2</sub>) by renewable electricity to produce multicarbon chemicals, such as ethylene (C<sub>2</sub>H<sub>4</sub>), continues to be a challenge because of insufficient Faradaic efficiency, low production rates, and complex mechanistic pathways. Here, we report that the rate-determining steps (RDS) on common copper (Cu) surfaces diverge in CO<sub>2</sub> electroreduction, leading to distinct catalytic performances. Through a combination of experimental and computational studies, we reveal that C─C bond-making is the RDS on Cu(100), whereas the protonation of *CO with adsorbed water becomes rate-limiting on Cu(111) with a higher energy barrier. On an oxide-derived Cu(100)-dominant Cu catalyst, we reach a high C<sub>2</sub>H<sub>4</sub> Faradaic efficiency of 72%, partial current density of 359 mA cm<sup>-2</sup>, and long-term stability exceeding 100 h at 500 mA cm<sup>-2</sup>, greatly outperforming its Cu(111)-rich counterpart. We further demonstrate constant C<sub>2</sub>H<sub>4</sub> selectivity of >60% over 70 h in a membrane electrode assembly electrolyzer with a full-cell energy efficiency of 23.4%.