Supramolecular Engineering to Improve Electrocatalytic CO₂ Reduction Activity of Cu₂ O

Electrochemical conversion of CO₂ into value-added fuels and feedstocks attracts worldwide attention to mitigate energy and environmental problems. However, pursuing highly efficient electrocatalyst is still a challenge. In this study, cuprous oxide (Cu₂ O) modified by cucurbit[6]urils (Q[6]), a kind of rigid macromolecule, is found to act as an efficient supramolecular inorganic nanocomposite catalyst for the electrochemical CO₂ reduction reaction (CO₂ RR) to C₁ fuels. This catalyst affords a high total faradaic efficiency (FE_CO+formate ) of 93.96 % at a potential of -0.7 V vs. reversible hydrogen electrode and over 85 % from -0.6 to -0.9 V in 0.5 M KHCO₃ , which is higher than that of pure Cu₂ O (39.89 %). The enhancements in selectivity and activity for CO₂ RR could significantly benefit from the strong CO₂ adsorption capacity and hydrophobic nature of the cavity of Q[6], which simultaneously trap gaseous reactants near the catalyst to tune the local environment and limit the diffusion of water molecules. This study provides a strategy to adjust catalytic environments through supramolecular engineering.