(654a) Organic-Inorganic Interface Enhanced CO2 Capture and Conversion

CO₂ reactive capture and conversion, e.g., CO₂ reduction reaction (CO₂RR) into value-added hydrocarbons and alcohols, over organic-inorganic interface become a promising strategy to close the carbon loop and form a net-zero-carbon process. However, the mechanism of CO₂RR to valuable hydrocarbons and alcohols at such structure-sensitive organic-inorganic interface is unclear under working conditions.

To mitigate the above mechanism challenge, we designed an organic-inorganic interface, i.e., aminothioalte self-assembled monolayer (SAM)-modulated Cu interface (i.e., Cu-S-C_nH_2n-NH₂, n = 2, 6, 11). Grand canonical density functional theory (GC-DFT) simulation and mean-field microkinetic model are applied to prove that dual-active sites (organic nitrogen site (-NH₂), inorganic Cu site) at the interface promoted CO₂ capture, first-proton transfer activation (i.e., COOH^* formation), and its selectivity to C₂ (i.e., carbon-carbon (C-C) coupling). More specifically, our results (Figure 1) show that (1) the ligands prefer a flat-lying configuration at low coverage, while they favor upright configuration at high coverage due to the lateral interactions; (2) the ligands are stable over the Cu surface when the coverage is lower than ¼ ML. In addition, the ligand with a longer alkyl chain length is more stable; (3) aminothiolate ligands provide H bond and active N site to promote COOH^*formation at Cu and N site, respectively, thus improving the activity; and (4) low coverage of aminothiolate ligand at flat-lying configuration decreases the activation barrier of C-C coupling up to 0.64 eV compared to that of bare Cu, facilitating the selectivity of C₂ species. The simulation results will be further validated with CO₂RR experiments. Overall, this research provides an innovative picture of electrocatalysis at hybrid organic-inorganic interfaces, and specifically their roles in increasing catalytic activity and selectivity.

References

1. Wan, M.; Gu, Z.; Che, F., ChemCatChem 2022, 14, e202101224.
2. Wan, M.; Gu, Z.; Shi, F.; Che, F., Chem Catalysis 2023. Under review.