Theoretical Investigation of Cu-Au Alloy for Carbon Dioxide Electroreduction: Cu/Au Ratio Determining C 1 /C 2 Selectivity.

Copper-gold alloy exhibits excellent catalytic performance for the carbon dioxide electroreduction (CO 2 ER) reaction, but the mechanism of the effect of the Cu/Au ratio on the selectivity of C 1 /C 2 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 CO 2 ER to C 2 H 4 and C 2 H 5 OH 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 CO 2 ER to CO ( U L = -0.32 V). Furthermore, the Cu3Au1(100) surface exhibits the best coupling performance, and ethanol is the dominant product for CO 2 ER to C 2 products. Our work provides a useful guideline for further developing CO 2 ER electrocatalysts.