Accelerating electrochemical CO(2) reduction to multi-carbon products via asymmetric intermediate binding at confined nanointerfaces

Electrochemical CO(2) reduction (CO(2)R) to ethylene and ethanol enables the long-term storage of renewable electricity in valuable multi-carbon (C(2+)) chemicals. However, carbon–carbon (C–C) coupling, the rate-determining step in CO(2)R to C(2+) conversion, has low efficiency and poor stability, especially in acid conditions. Here we find that, through alloying strategies, neighbouring binary sites enable asymmetric CO binding energies to promote CO(2)-to-C(2+) electroreduction beyond the scaling-relation-determined activity limits on single-metal surfaces. We fabricate experimentally a series of Zn incorporated Cu catalysts that show increased asymmetric CO* binding and surface CO* coverage for fast C–C coupling and the consequent hydrogenation under electrochemical reduction conditions. Further optimization of the reaction environment at nanointerfaces suppresses hydrogen evolution and improves CO(2) utilization under acidic conditions. We achieve, as a result, a high 31 ± 2% single-pass CO(2)-to-C(2+) yield in a mild-acid pH 4 electrolyte with >80% single-pass CO(2) utilization efficiency. In a single CO(2)R flow cell electrolyzer, we realize a combined performance of 91 ± 2% C(2+) Faradaic efficiency with notable 73 ± 2% ethylene Faradaic efficiency, 31 ± 2% full-cell C(2+) energy efficiency, and 24 ± 1% single-pass CO(2) conversion at a commercially relevant current density of 150 mA cm(−2) over 150 h.