(111) Facet‐oriented Cu2Mg Intermetallic Compound with Cu3‐Mg Sites for CO2 Electroreduction to Ethanol with Industrial Current Density

Abstract The efficient ethanol electrosynthesis from CO 2 is challenging with low selectivity at high CO 2 electrolysis rates, due to the competition with H 2 and other reduction products. Copper‐based bimetallic electrocatalysts are potential candidates for the CO 2 ‐to‐ethanol conversion, but the secondary metal has mainly been focused on active components (such as Ag, Sn) for CO 2 electroreduction, which also promote selectivity of ethylene or other reduction products rather than ethanol. Limited attention has been given to alkali‐earth metals due to their inherently active chemical property. Herein, we rationally synthesized a (111) facet‐oriented nano Cu 2 Mg (designated as Cu 2 Mg(111)) intermetallic compound with high‐density ordered Cu 3 ‐Mg sites. The in situ Raman spectroscopy and density function theory calculations revealed that the Cu 3 − − ‐Mg − + active sites allowed to increase *CO surface coverage, decrease reaction energy for *CO−CO coupling, and stabilize *CHCHOH intermediates, thus promoting the ethanol formation pathway. The Cu 2 Mg(111) catalyst exhibited a high FE C2H5OH of 76.2±4.8 % at 600 mA⋅cm −2 , and a peak value of | j C2H5OH | of 720±34 mA⋅cm −2 , almost 4 times of that using conventional Cu 2 Mg with (311) facets, comparable to the best reported values for the CO 2 ‐to‐ethanol electroreduction.