Amino Assisted Protonation for Carbon−Carbon Coupling During Electroreduction of Carbon Dioxide to Ethylene on Copper(I) Oxide.

The development of effective catalysts for the electrocatalytic carbon dioxide reduction reaction (CO2RR) to two‐carbon (C2) products is a practical approach to solve the energy crisis and stabilize the carbon cycle of the ecosystem. The production of electrocatalytic CO2RR with copper metal shows low selectivity and mainly generates one‐carbon (C1) products, hindering its wide practical application. The use of copper (I) oxide (Cu2O) in electrocatalysis has attracted intense research attention because it can more efficiently produce C2 products with high energy density such as ethylene (C2H4) and ethane (C2H6). We use an amino‐modified Cu2O catalyst (NH2−Cu2O) for electrocatalytic CO2RR to obtain significantly increased production of the CO and C2 products. Electrochemical in‐situ infrared spectroscopy analysis was used to detect the presence of the *COOH and *CHO reaction intermediates. Density functional theory calculations showed that the amino (−NH2) modification reduces the free energy of the *CO→*CHO reaction that is the rate‐determining step in C2H4 production. Our results show that amino modification can promote the protonation of *CO and *CHO carbon‐carbon coupling to produce C2H4. Thus, amino‐modified copper‐based catalysts are promising materials for application in electrocatalytic CO2RR to multi‐carbon products. [ABSTRACT FROM AUTHOR]