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

Electrocatalytic carbon dioxide reduction reaction (CO 2 RR) 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 2+ ) products. Herein we report the coordination environment engineering of metal centers in coordination polymers for efficient electroreduction of CO 2 to C 2+ products under neutral conditions. Significantly, the Cu coordination polymer with Cu-N 2 S 2 coordination configuration (Cu-N-S) demonstrates superior Faradaic efficiencies of 61.2% and 82.2% for ethylene and C 2+ products, respectively, compared to the selective formic acid generation on an analogous polymer with the Cu-I 2 S 2 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 2+ 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 2+ products. Consequently, Cu-N-S displays a stronger reaction trend toward the generation of C 2+ products, while Cu-I-S favors the formation of formic acid due to the suppression of C-C couplings for C 2+ pathways with large energy barriers.