Ab initio study for late steps of CO 2 and CO electroreduction: from CHCO* toward C 2 products on Cu and CuZn nanoclusters.

Electroreduction of CO 2 to C 2 products such as ethanol is motivated by its potential application to satisfy global energy demand in a more sustainable and renewable way. Cooper-based catalysts have exhibited highlighted performance in obtaining C 2 products, but large overpotentials and poor selectivity are still challenging. Herein, we employed density functional theory calculations and the computational hydrogen electrode model to study the impact of CuZn alloys on the mechanism and selectivity of CO 2 and CO electroreduction to C 2 products. On both clusters, the preferred pathway to ethanol and ethylene shares a common intermediate: CH 2 CHO*. On Cu 55 , ethanol formation would occur at lower electrode potential than the formation of ethylene, which agrees with experimental studies. Since Cu 42 Zn 13 increases the Gibbs free energy change between CH 2 CHO* and adsorbed acetaldehyde, the alloy exhibited lower selectivity toward ethanol than Cu 55 cluster. The role of Zn is mainly related to the stronger adsorption of the intermediates on Cu 42 Zn 13 than in the Cu 55 group. Our results suggested that the d states of Zn are involved in the adsorption of intermediates, strengthening the interaction.