Theoretical Investigation of Cu–Au Alloy for Carbon Dioxide Electroreduction: Cu/Au Ratio Determining C1/C2 Selectivity

Copper–gold alloy exhibits excellent catalytic performance for the carbon dioxide electroreduction (CO2ER) reaction, but the mechanism of the effect of the Cu/Au ratio on the selectivity of C1/C2 products has not been carefully investigated. In this work, (100) and (111) surfaces of three CuAu alloys with different Cu/Au (3:1, 1:1, 1:3) ratios are constructed. The properties of CuAu surfaces like density of states, Bader charge, and the whole CO2ER to C2H4 and C2H5OH mechanisms are investigated. Our calculation reveals that the adsorption capacity of the catalyst surface for the intermediates *COOH and *CO is enhanced with the increase of the Au ratio. The calculation results show that the Cu1Au1(100) surface has the highest activity for CO2ER to CO (U L = −0.32 V). Furthermore, the Cu3Au1(100) surface exhibits the best coupling performance, and ethanol is the dominant product for CO2ER to C2 products. Our work provides a useful guideline for further developing CO2ER electrocatalysts.