Cucurbit[6]uril-modified copper catalysts with stabilized Cu+ sites for C2+ production at ampere-level current densities

Achieving high activity and selectivity for multi-carbon (C 2+ ) products on copper-based catalysts at ampere-level current densities is important for advancing industrial electrochemical CO 2 reduction reaction (eCO 2 RR). However, oxidative copper species are prone to reduction to metallic copper at high reduction potentials, causing the decline of selectivity and stability for C 2+ products. Herein, we report that Cucurbit[6]uril (CB[6])-modified copper nanoparticles promote eCO 2 RR via stabilizing Cu + sites at ampere-level current densities. The Cu-CB[6]-3 catalyst exhibited the highest C 2+ productivity with a faradaic efficiency of 72.2 ± 1.0 % at a current density of 1.0 A cm −2 , and the corresponding potential was −1.2 V vs. RHE. Detailed systematical spectroscopic analyses revealed that the main reason for boosting the C–C coupling is that the strong coordination interaction and molecular-level confinement of CO 2 and reaction intermediates of CB[6] can not only stabilize Cu + at higher current densities, but also accelerate the reaction kinetics. Simultaneously, the hydrophobic inner cavity and hydrophilic outer surface of CB[6] molecules ensure the smooth progress of eCO 2 RR while suppressing the hydrogen evolution reaction, resulting in high C 2+ selectivity and long-term stability. This work provides an approach to design highly efficient catalysts for industrial eCO 2 RR.