Modulation of the Coordination Environment of Copper for Stable CO 2 Electroreduction with Tunable Selectivity.

Manipulating the product selectivity of an electrochemical CO 2 reduction reaction (CO 2 RR) is challenging due to the unclear and uncontrollable active sites. Here, we report stable CO 2 RR operation with tunable product selectivity over a family of molecule-modulated copper catalysts. The coordination environment of Cu in catalysts is modulated by an imidazole-based molecule via different synthetic routes. Various carbonaceous products ranging from carbon monoxide, methane, and ethylene were selectively produced via, respectively, tuning the coordination environment of copper atoms from Cu-N, Cu-C, and Cu-Cu. Density functional theory (DFT) calculations reveal that the Cu-N sites weaken the adsorption energy of the *CO intermediate, which is beneficial for CO desorption. The Cu-C and Cu-Cu sites, respectively, facilitate the formation of *OCOH and *(CO) 2 intermediates, favoring the CH 4 and C 2 H 4 pathways. This work provides a stable and simple model system for studying the influence of coordination elements on the product selectivity of CO 2 RR.