The Influence of Ni Addition in the Mechanism of CO 2 Electroreduction on Cu Crystals-Mechanistic Insight from DFT Simulations.

We present a DFT analysis of the role of the Cu-Ni synergistic effect for the CO 2 reduction to C 2 H 4 , in comparison to the pure Cu catalyst. The analysis is focused on the thermodynamic stability of reactive intermediates along the proposed pathway of C 2 species formation. We have observed that the potential needed for the reaction decreases with the addition of Ni in the investigated model. In addition, we have observed the differences in the preferred pathway based on the significant differences in stability of the reactive intermediates depending on th Cu:Ni ratio. The results suggest that despite the fact the Cu surface is always exposed, and it is the only one that is able to directly interact with the intermediates, the presence of the Ni in the underlying sections of the crystal is significant enough to change the mechanism of the reaction.