Cation-induced changes in the inner- and outer-sphere mechanisms of electrocatalytic CO<sub>2</sub> reduction.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37993426.
- Also identified by DOI 10.1038/s41467-023-43300-4 and PMC identifier 10665450.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The underlying mechanism of cation effects on CO<sub>2</sub>RR remains debated. Herein, we study cation effects by simulating both outer-sphere electron transfer (OS-ET) and inner-sphere electron transfer (IS-ET) pathways during CO<sub>2</sub>RR via constrained density functional theory molecular dynamics (cDFT-MD) and slow-growth DFT-MD (SG-DFT-MD), respectively. Our results show without any cations, only OS-ET is feasible with a barrier of 1.21 eV. In the presence of K<sup>+</sup> (Li<sup>+</sup>), OS-ET shows a very high barrier of 2.93 eV (4.15 eV) thus being prohibited. However, cations promote CO<sub>2</sub> activation through IS-ET with the barrier of only 0.61 eV (K<sup>+</sup>) and 0.91 eV (Li<sup>+</sup>), generating the key intermediate (adsorbed CO[Formula: see text]). Without cations, CO<sub>2</sub>-to-CO[Formula: see text](ads) conversion cannot proceed. Our findings reveal cation effects arise from short-range Coulomb interactions with reaction intermediates. These results disclose that cations modulate the inner- and outer-sphere pathways of CO<sub>2</sub>RR, offering substantial insights on the cation specificity in the initial CO<sub>2</sub>RR steps.