Coordination Environment Engineering of Metal Centers in Coordination Polymers for Selective Carbon Dioxide Electroreduction toward Multicarbon Products.

Electrocatalytic carbon dioxide reduction reaction (CORR) toward value-added chemicals/fuels has offered a sustainable strategy to achieve a carbon-neutral energy cycle. However, it remains a great challenge to controllably and precisely regulate the coordination environment of active sites in catalysts for efficient generation of targeted products, especially the multicarbon (C) products. Herein we report the coordination environment engineering of metal centers in coordination polymers for efficient electroreduction of CO to C products under neutral conditions. Significantly, the Cu coordination polymer with Cu-NS coordination configuration (Cu-N-S) demonstrates superior Faradaic efficiencies of 61.2% and 82.2% for ethylene and C products, respectively, compared to the selective formic acid generation on an analogous polymer with the Cu-IS coordination mode (Cu-I-S). In situ studies reveal the balanced formation of atop and bridge *CO intermediates on Cu-N-S, promoting C-C coupling for C production. Theoretical calculations suggest that coordination environment engineering can induce electronic modulations in Cu active sites, where the d-band center of Cu is upshifted in Cu-N-S with stronger selectivity to the C products. Consequently, Cu-N-S displays a stronger reaction trend toward the generation of C products, while Cu-I-S favors the formation of formic acid due to the suppression of C-C couplings for C pathways with large energy barriers.