Self-assembled Cuprous Coordination Polymer as a Catalyst for CO₂ Electrochemical Reduction into C₂ Products

C₂ production with conventional metal complex catalysts has been a significant challenge. Here, we present the electrochemical reduction of CO₂ into C₂ products such as ethylene and ethanol with high selectivity using a self-assembled cuprous coordination polymer nanoparticle (Cu-SCP). The features of the Cu-SCP catalyst are the arrangement of Cu atoms in close proximity, similar to that in metallic Cu, and a stable Cu­(I) oxidation state throughout the reaction due to the coordination of ligands with Cu atoms, which inhibits conversion into Cu metal particles. The Cu-SCP also exhibits activity for C₂ production that is superior to that of a Cu metal electrode, without modification of the carbon particles and/or ionomers or continuous flow of the highly alkaline electrolyte, which will simplify the fabrication of a CO₂ electrolyzer. The Cu-SCP can be synthesized by a facile process that utilizes a heterogeneous reaction, and the product selectivity can be changed by replacement of the organic ligands, which should open up possibilities for the design of other CO₂ reduction catalysts.