Supramolecular Engineering to Improve Electrocatalytic CO 2 Reduction Activity of Cu 2 O

Abstract Electrochemical conversion of CO 2 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 (Cu 2 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 CO 2 reduction reaction (CO 2 RR) to C 1 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 KHCO 3 , which is higher than that of pure Cu 2 O (39.89 %). The enhancements in selectivity and activity for CO 2 RR could significantly benefit from the strong CO 2 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.