Modulation of the Coordination Environment of Copper for Stable CO2 Electroreduction with Tunable Selectivity

Abstract

Manipulating the product selectivity of an electrochemical CO2 reduction reaction (CO2RR) is challenging due to the unclear and uncontrollable active sites. Here, we report stable CO2RR 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 CH4 and C2H4 pathways. This work provides a stable and simple model system for studying the influence of coordination elements on the product selectivity of CO2RR.